Academic literature on the topic 'Photosynthetic parameter'
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Journal articles on the topic "Photosynthetic parameter"
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Huot, Y., M. Babin, and F. Bruyant. "Photosynthetic parameters in the Beaufort Sea in relation to the phytoplankton community structure." Biogeosciences Discussions 10, no. 1 (January 30, 2013): 1551–76. http://dx.doi.org/10.5194/bgd-10-1551-2013.
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Abstract. To model phytoplankton primary production from remotely sensed data a method to estimate photosynthetic parameters describing the photosynthetic rates per unit biomass is required. Variability in these parameters must be related to environmental variables that are measurable remotely. In the Arctic, a limited number of measurements of photosynthetic parameter have been carried out with the concurrent environmental variables needed. Therefore, to improve the accuracy of remote estimates of phytoplankton primary production as well as our ability to predict changes in the future such measurements and relationship to environmental variables are required. During the MALINA cruise, a large dataset of these parameters were obtained. Together with previously published datasets, we use environmental and trophic variables to provide functional relationships for these parameters. In particular, we describe several specific aspects: the maximum rate of photosynthesis (Pmaxchl) normalized to chlorophyll decreases with depth and is higher for communities composed of large cells; the saturation parameter (Ek) decreases with depth but is independent of the community structure; and the initial slope of the photosynthesis versus irradiance curve (αchl) normalized to chlorophyll is independent of depth but is higher for communities composed of larger cells. The photosynthetic parameters were not influenced by temperature over the range encountered during the cruise (−2 to 8 °C).
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Jasper, Stephen, and Max L. Bothwell. "Photosynthetic Characteristics of Lotic Periphyton." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 10 (October 1, 1986): 1960–69. http://dx.doi.org/10.1139/f86-241.
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Periphyton communities, grown in continuous-flow troughs, were suspended in filtered river water and placed in a photosynthesis–light incubator similar to those used for phytoplankton. A three-parameter equation was fitted to the incubator data. Seasonally the initial slope, α, ranged from 12.1 to 53.6 μg C∙(mg Chl a)−1∙h−1∙(μEinst.∙m−2∙s−1)−1; the maximum photosynthetic rate, PBmax, varied from 1.16 to 5.49 mgC∙(mg Chl a)−1∙h−1; and the inhibition parameter, Ib, ranged from 1500 to 6900 μEinst.∙m−2∙s−1. These values are similar to those reported for other periphyton and phytoplankton. PBmax strongly correlated with light history, whereas inhibition was inversely related to water temperature, α did not correlate with either irradiance or temperature but with changes in average cell size. Seasonal variations in the light level optimal for photosynthesis, Im, suggested a period in late winter and early spring for potentially serious inhibition of photosynthesis. These Chl a normalized photosynthetic parameters were unaffected by changes in concentration of the growth-limiting nutrient, phosphorus.
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Huot, Y., M. Babin, and F. Bruyant. "Photosynthetic parameters in the Beaufort Sea in relation to the phytoplankton community structure." Biogeosciences 10, no. 5 (May 29, 2013): 3445–54. http://dx.doi.org/10.5194/bg-10-3445-2013.
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Abstract. To model phytoplankton primary production from remotely sensed data, a method to estimate photosynthetic parameters describing the photosynthetic rates per unit biomass is required. Variability in these parameters must be related to environmental variables that are measurable remotely. In the Arctic, a limited number of measurements of photosynthetic parameters have been carried out with the concurrent environmental variables needed. Such measurements and their relationship to environmental variables will be required to improve the accuracy of remotely sensed estimates of phytoplankton primary production and our ability to predict future changes. During the MALINA cruise, a large dataset of these parameters was obtained. Together with previously published datasets, we use environmental and trophic variables to provide functional relationships for these parameters. In particular, we describe several specific aspects: the maximum rate of photosynthesis (Pmaxchl) normalized to chlorophyll decreases with depth and is higher for communities composed of large cells; the saturation parameter (Ek) decreases with depth but is independent of the community structure; and the initial slope of the photosynthesis versus irradiance curve (αchl) normalized to chlorophyll is independent of depth but is higher for communities composed of larger cells. The photosynthetic parameters were not influenced by temperature over the range encountered during the cruise (−2 to 8 °C).
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Vieira Jr., Jair, and Orlando Necchi Jr. "Photosynthetic characteristics of a tropical population of Nitella cernua (Characeae, Chlorophyta)." Brazilian Journal of Plant Physiology 18, no. 3 (September 2006): 379–88. http://dx.doi.org/10.1590/s1677-04202006000300004.
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Photosynthetic characteristics (assessed by chlorophyll fluorescence and O2 evolution) were analysed monthly during one year in a tropical population of Nitella cernua from southeastern Brazil (20º50'32" S, 49º26'15" W). Parameters derived from photosynthesis-irradiance (PI) curves by fluorescence (high values of the photosynthetic parameter, Ik, and lack or low values of photoinhibition, beta) suggested adaptation to high irradiance, whereas those by O2 evolution showed a different pattern (low values of Ik and compensation irradiance, Ic, high values of photosynthetic efficiency, alpha, and photoinhibition). Parameters from PI curves by O2 evolution suggested light acclimation: Ik and maximum photosynthetic rate, Pmax (as rETR, relative electron transfer rate) increased, whereas a became significantly lower under higher irradiance (winter). This pattern is an adjustment of both number and size of photosynthetic units. Photosynthetic performance assessed by fluorescence revealed two seasonal periods: higher values of Pmax (rETR), Ik and non-photochemical quenching from October to March (rainy season), and lower values from April to October (dry season). Temperature responses were observed only in summer, but temperature optima were different between methods: peaks of net photosynthesis occurred at 20ºC, whereas rETR increased towards higher temperatures (up to 30ºC). Dark respiration increased with higher temperatures. Current velocity had a stimulatory effect on photosynthetic rates, as suggested by positive correlations with Pmax (rETR) and alpha. pH experiments revealed highest net photosynthetic rates under pH 4.0, suggesting higher affinity for CO2 than HCO3-. This broad range of responses of photosynthetic characteristics of this N. cernua population to irradiance, temperature, and pH/inorganic carbon reflects a wide tolerance to variations in these environmental variables, which probably contribute to the wide distribution of this species.
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Ma, Xuemei, Qiang Liu, Zhidong Zhang, Zewen Zhang, Zeyu Zhou, Yu Jiang, and Xuanrui Huang. "Effects of photosynthetic models on the calculation results of photosynthetic response parameters in young Larix principis-rupprechtii Mayr. plantation." PLOS ONE 16, no. 12 (December 31, 2021): e0261683. http://dx.doi.org/10.1371/journal.pone.0261683.
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Accurately predicting the crown photosynthesis of trees is necessary for better understanding the C circle in terrestrial ecosystem. However, modeling crown for individual tree is still challenging with the complex crown structure and changeable environmental conditions. This study was conducted to explore model in modeling the photosynthesis light response curve of the tree crown of young Larix principis-rupprechtii Mayr. Plantation. The rectangular hyperbolic model (RHM), non-rectangular hyperbolic model (NRHM), exponential model (EM) and modified rectangular hyperbolic model (MRHM) were used to model the photosynthetic light response curves. The fitting accuracy of these models was tested by comparing determinants coefficients (R2), mean square errors (MSE) and Akaike information criterion (AIC). The results showed that the mean value of R2 of MRHM (R2 = 0.9687) was the highest, whereas MSE value (MSE = 0.0748) and AIC value (AIC = -39.21) were the lowest. The order of fitting accuracy of the four models for Pn-PAR response curve was as follows: MRHM > EM > NRHM > RHM. In addition, the light saturation point (LSP) obtained by MRHM was slightly lower than the observed values, whereas the maximum net photosynthetic rates (Pmax) modeled by the four models were close to the measured values. Therefore, MRHM was superior to other three models in describing the photosynthetic response curve, the accurate values were that the quantum efficiency (α), maximum net photosynthetic rate (Pmax), light saturation point (LSP), light compensation point (LCP) and respiration rate (Rd) were 0.06, 6.06 μmol·m-2s-1, 802.68 μmol·m-2s-1, 10.76 μmol·m-2s-1 and 0.60 μmol·m-2s-1. Moreover, the photosynthetic response parameters values among different layers were also significant. Our findings have critical implications for parameter calibration of photosynthetic models and thus robust prediction of photosynthetic response in forests.
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Yin, Xiaohong, Xing Li, Jiaxin Xie, Zhengwu Xiao, Chunrong Zhao, Yuling Kang, Chuanming Zhou, Fangbo Cao, Jiana Chen, and Min Huang. "Do You Get What You Pay for? Evaluating the Reliability of an Inexpensive Portable Photosynthesis System in Measuring Gas Exchange in Rice (Oryza sativa L.) Leaves." Agronomy 12, no. 11 (November 7, 2022): 2775. http://dx.doi.org/10.3390/agronomy12112775.
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The availability of commercially available portable photosynthesis systems has facilitated widespread photosynthetic research. Our study aimed to evaluate the reliability of a recently developed inexpensive portable photosynthesis system, Yaxin-1105, in measuring gas exchange in rice (Oryza sativa L.) leaves. Gas exchange parameters, including net photosynthetic rate (Anet), stomatal conductance (gs), intercellular CO2 concentration (Ci), and transpiration rate (E), were measured on 88 rice leaves across seven rice cultivars and three growth stages (panicle initiation, heading, and early ripening), using both Yaxin-1105 and LI-6400XT. There were significant difference between each gas exchange parameter at each growth stage measured by Yaxin-1105 and LI-6400XT, except Ci at the heading stage. Mean Anet, gs, and E measured by Yaxin-1105 were 26–66% lower than those measured by LI-6400XT at panicle initiation, heading, and early ripening stages. Mean Ci measured by Yaxin-1105 was 13–22% higher than that measured by LI-6400XT at panicle initiation and early ripening stages. The coefficients of determination between each gas exchange parameter measured by Yaxin-1105 and by LI-6400XT at panicle initiation, heading, and early ripening stages ranged from only 0.0007 to 0.1889. These results indicate that the Yaxin-1105 is not a reliable tool for measuring gas exchange in rice leaves.
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RACZ, Ionuț, Rozalia KADAR, Diana HIRISCǍU, Marius BǍRDAŞ, Florin Dumitru BORA, Camelia URDǍ, and Adina TǍRǍU. "Evaluation of Photosynthesis Capacity of Some Winter Wheat Genotypes in Transylvanian Plain Conditions." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 75, no. 1 (May 18, 2018): 56. http://dx.doi.org/10.15835/buasvmcn-agr:004617.
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Leaf photosynthetic capacity is a key parameter determining crop yield; it is enhanced by moderate soil moisture and reduced in both severe water deficit and excessive water conditions. The aim of this work was to evaluate the wheat variety photosynthetic capacity in two main phenological stages. The evaluation of photosynthesis capacity of studied winter wheat varieties in Transylvanian Plain conditions offer relevant information on Romanian genetic material type and paving the way of new research directed to a new wheat breeding program criteria and for improvement of those.
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Sun, Zhongqiu, Songxi Yang, Shuo Shi, and Jian Yang. "The Effect of Principal Component Analysis Parameters on Solar-Induced Chlorophyll Fluorescence Signal Extraction." Applied Sciences 11, no. 11 (May 26, 2021): 4883. http://dx.doi.org/10.3390/app11114883.
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Solar-induced chlorophyll fluorescence (SIF), one of the three main releasing pathways of vegetation-absorbed photosynthetic active radiation, has been proven as an effective monitoring implementation of leaf photosynthesis, canopy growth, and ecological diversity. There exist three categories of SIF retrieval methods, and the principal component analysis (PCA) retrieval method is obtrusively eye-catching due to its brief, data-driven characteristics. However, we still lack a lucid understanding of PCA’s parameter settings. In this study, we examined if principal component numbers and retrieval band regions could have effects on the accuracy of SIF inversion under two controlled experiments. The results revealed that the near-infrared region could remarkably boost SIF’s retrieval accuracy, whereas red and near-infrared bands caused anomalous values, which subverted a traditional view that more retrieval regions might provide more photosynthetic information. Furthermore, the results demonstrated that three principal components would benefit more in PCA-based SIF retrieval. These arguments further help elucidate the more in-depth influence of the parameters on the PCA retrieval method, which unveil the potential effects of different parameters and give a parameter-setting foundation for the PCA retrieval method, in addition to assisting retrieval achievements.
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Osei-Kwarteng, Mildred, Emmanuel Ayipio, Dany Moualeu-Ngangue, Gerhard Buck-Sorlin, and Hartmut Stützel. "Interspecific variation in leaf traits, photosynthetic light response, and whole-plant productivity in amaranths (Amaranthus spp. L.)." PLOS ONE 17, no. 6 (June 30, 2022): e0270674. http://dx.doi.org/10.1371/journal.pone.0270674.
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Photosynthetic light response curve parameters help us understand the interspecific variation in photosynthetic traits, leaf acclimation status, carbon uptake, and plant productivity in specific environments. These parameters are also influenced by leaf traits which rely on species and growth environment. In accessions of four amaranth species (Amaranthus. hybridus, A. dubius, A. hypochondriacus, and A. cruentus), we determined variations in the net photosynthetic light response curves and leaf traits, and analysed the relationships between maximum gross photosynthetic rate, leaf traits, and whole-plant productivity. Non-rectangular hyperbolae were used for the net photosynthesis light response curves. Maximum gross photosynthetic rate (Pgmax) was the only variant parameter among the species, ranging from 22.29 to 34.21 μmol m–2 s–1. Interspecific variation existed for all the leaf traits except leaf mass per area and leaf inclination angle. Stomatal conductance, nitrogen, chlorophyll, and carotenoid contents, as well as leaf area correlated with Pgmax. Stomatal conductance and leaf nitrogen explained much of the variation in Pgmax at the leaf level. At the plant level, the slope between absolute growth rate and leaf area showed a strong linear relationship with Pgmax. Overall, A. hybridus and A. cruentus exhibited higher Pgmax at the leaf level and light use efficiency at the whole-plant level than A. dubius, and A. hypochondriacus. Thus, A. hybridus and A. cruentus tended to be more efficient with respect to carbon assimilation. These findings highlight the correlation between leaf photosynthetic characteristics, other leaf traits, and whole plant productivity in amaranths. Future studies may explore more species and accessions of Amaranthus at different locations or light environments.
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Manojkumar, K., S. Vincent, M. Raveendran, R. Anandham, V. Babu Rajendra Prasad, A. Mothilal, and S. Anandakumar. "Effect of drought on gas exchange and chlorophyll fluorescence of groundnut genotypes." Journal of Applied and Natural Science 13, no. 4 (December 16, 2021): 1478–87. http://dx.doi.org/10.31018/jans.v13i4.3145.
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Drought is one of the major threats to groundnut productivity, causing a greater loss than any other abiotic factor. Water stress conditions alter plant photosynthetic activity, impacting future growth and assimilating mobilization towards sink tissues. The purpose of this study was to investigate how drought impacts the photosynthesis of plants and its links to drought tolerance. The influence of reproductive stage drought on photosynthetic activity and chlorophyll fluorescence of groundnut is well studied. The experiment was conducted in Kharif 2019 (Jul-Sep), where recent series in groundnut genotypes (60 nos) sown under rainfed conditions and water stress was created by withholding irrigation for 20 days between 35-55 days after sowing in the field to simulate drought conditions. Imposition of water deficit stress reduced PS II efficiency, which significantly altered the photosynthetic rate in the leaf. Observation of gas exchange parameters viz., photosynthetic rate, stomatal conductance and transpiration rate after 20 days of stress imposition revealed that of all 60 genotypes, 20 genotypes (VG 17008, VG 17046VG 18005, VG 18102, VG 18077, VG 19572, VG 19709, VG 18111, VG19561, VG19576, VG 19620, VG 19681, VG 19688, etc.,) had better Photosynthetic rate, Stomatal conductance. Similarly, PS II efficiency analyzed through fluorescence meter revealed that among the 60 and all the genotypes given above recorded higher value in Fv/Fm. Results obtained from Cluster analysis and PCA confirmed that photosynthetic rate and Fv/Fm is useful parameter in screening adapted cultivars under drought stress. These findings lay the groundwork for a future study to decipher the molecular pathways underpinning groundnut drought resistance.
Dissertations / Theses on the topic "Photosynthetic parameter"
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Bricker, Kelley J. "The Effects of Light and Nutrients on Algal Photosynthetic Parameters." Miami University Honors Theses / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1240590016.
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Srirangam, Siva. "Retrieval of Oceanic and Physiological Parameters Using Computational Intelligence." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/SrirangamS2004.pdf.
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Daymond, Andrew James. "An investigation into physiological parameters underlying yield variation between different varieties of cocoa (Theobroma cacao L.)." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325213.
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Pereira, Dinaelza Castelo. "Efeito dos parâmetros ambientais sobre a macroalga Gracilaria domingensis: estratégias de aclimatação e fotoproteção na espécie." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-19012015-152336/.
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Em seu habitat natural as algas estão sujeitas a ação simultânea de vários fatores, como radiação (fotossinteticamente ativa e ultravioleta), temperatura, salinidade e disponibilidade de nutrientes, entre outros. A variação desses fatores no ambiente natural ocorre de forma coletiva e uma rápida resposta do organismo é determinante pra sua sobrevivência. Neste trabalho foram conduzidos experimentos relacionados aos efeitos da variação nos parâmetros ambientais sobre a macroalga Gracilaria domingensis. Três linhagens cromáticas dessa espécie foram cultivadas no mar, em diferentes épocas do ano (estações chuvosa e seca). Os dados fotossintéticos e bioquímicos foram acessados em uma escala de tempo referente às variações observadas durante o período de luz do dia e em uma escala referente às variações observadas em semanas. Os resultados obtidos a partir de análises dos parâmetros fotossintéticos, conteúdo pigmentar, concentração de glutationa, concentração de aminoácidos tipo micosporina, conteúdo tecidual de carbono, nitrogênio e fósforo, teor de lipídeos e ácidos graxos e rendimento do ágar mostraram alterações no perfil bioquímico e fisiológico da macroalga. Essas alterações foram correlacionadas com os fatores abióticos e sugerem alterações no metabolismo como uma das estratégias de aclimatação da espécie.In their natural habitat algae are exposed to simultaneous action of various factors, as radiation (photosynthetically active radiation and ultraviolet), temperature, salinity, nutrient availability and others. The variation in these factors in the natural environment occurs collectively and the algae capability for quick response is determinant for survival. In this work, studies related to the effects of environmental variation on the macroalgae Gracilaria domingensis were performed. Three chromatic strains were cultivated in the sea, at different times of the year (dry and rainy seasons). Biochemical and photosynthetic responses were accessed on a daylight time scale and on a week time scale. The reached results for photosynthetic parameters, pigment content, glutathione concentrations, mycosporine-like amino acids concentrations, carbon, nitrogen and phosphorus tissue content, lipids and fatty acids levels and agar yield, revealed the altered biochemical and physiological profile of macroalgae. These changes were environment related and suggest metabolism changes as a strategy used by this organism to acclimate.
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Khosravi, Narges [Verfasser], John P. [Akademischer Betreuer] Burrows, John P. [Gutachter] Burrows, and Justus [Gutachter] Notholt. "Space-Borne Retrieval of Solar-Induced Plant Fluorescence and its Relationship to Photosynthetic Parameters / Narges Khosravi ; Gutachter: John P. Burrows, Justus Notholt ; Betreuer: John P. Burrows." Bremen : Staats- und Universitätsbibliothek Bremen, 2017. http://d-nb.info/116577223X/34.
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Shaw, Shreya [Verfasser], and Robin [Akademischer Betreuer] Ghosh. "Comparative physiological parameters for the analysis of H2 production by the microalga Chlamydomonas reinhardtii and the photosynthetic purple bacterium Rhodospirillum rubrum / Shreya Shaw ; Betreuer: Robin Ghosh." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2019. http://d-nb.info/1209545098/34.
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Paleari, L. "IN SILICO IDEOTYPING: DEFINITION AND EVALUATION OF RICE IDEOTYPES IMPROVED FOR RESISTANCE/TOLERANCE TRAITS TO BIOTIC AND ABIOTIC STRESSORS UNDER CLIMATE CHANGE SCENARIOS." Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/483333.
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The development of new cultivars better adapted to specific growing conditions is a key strategy to meet an ever-increasing growing global food demand and search for more sustainable cropping systems. This is even more crucial in the context of a changing climate.
Ecophysiological models and advanced computational techniques (e.g., sensitivity analysis, SA) represent powerful tools to analyze genotype (G) by environment (E) interactions, thus supporting breeders in identifying key traits for specific agro-environmental contexts. However, limits for the effective use of mathematical models within breeding programs are represented by the uncertainty in the distribution of plant trait values, the lack of processes dealing with resistance/tolerance traits in most ideotyping studies, the partial suitability of current crop models for ideotyping purposes, and the absence of modelling tools directly usable by breeders.
The aim of this research was to address these issues improving methodologies already in use, proposing new paradigms for the development of crop models explicitly targeting ideotyping applications and developing tools that would encourage a deep interaction of the modelling and breeding communities. The focus was on rice, for its role as staple food for more than a half of world’s population, and on resistance/tolerance traits to biotic/abiotic stressors, for their central role in increasing crop adaptation. Moreover, current conditions and climate change projections were considered, to support the definition of strategies for breeding in the medium-long term.
A standard procedure to quantify − and manage − the impact of the uncertainty in the distribution of plant trait values was developed, using the WARM rice model and the Sobol’ method as case study. The approach is based on a SA (generating sample of parameter distributions) of a SA (generating samples of parameters for each generated distribution) using distributions of jackknife statistics calculated on literature values to reproduce the uncertainty in defining parameters distributions. As a practical implication, the procedure developed allows identifying plant traits whose uncertainty in distribution can alter ideotyping results, i.e., traits whose distributions could need to be refined.
Global SA was then used to identify rice traits putatively producing the largest yield benefits in five contrasting districts in the Philippines, India, China, Japan and Italy. The analysis involved phenotypic traits dealing with light interception, photosynthetic efficiency, tolerance to abiotic stressors, resistance to fungal pathogens and grain quality. Results suggested that breeding for traits involved with disease resistance and tolerance to cold- and heat-induced spikelet sterility could provide benefits similar to those obtained from improving traits affecting potential yield. Instead, advantages resulting from varying traits involved with grain quality were markedly frustrated by inter-annual weather variability. Since results highlighted strong G×E interactions, a new index to derive district-specific ideotypes was developed.
Given the key role of biotic/abiotic stressors in determining actual yield and the deep impact of related G×E interactions, a study was carried out by explicitly focusing on the definition of rice ideotypes improved for their resistance to fungal pathogens and tolerance to abiotic constraints (temperature shocks inducing sterility). The analysis was carried out at district level with a high spatial resolution (5 km × 5 km elementary simulation unit), targeting the improvement of the most representative 34 varieties in six Italian rice districts. Genetic improvement was simulated via the introgression of traits from donor varieties. Results clearly showed that breeders should focus on increasing resistance to blast disease, as this appears as a factor markedly limiting rice yields in Italy, regardless of the districts and climate scenarios, whereas benefits deriving from improving tolerance to cold-induced sterility could be markedly affected by G×E interactions.
To reduce the risk of discrepancies between in silico ideotypes and their in vivo realizations, both studies involved only model parameters with a close relationship with phenotypic traits breeders are working on. However, a long-term strategy to overcome limitations related with the partial suitability of available models would be building new ideotyping-specific models explicitly around traits involved in breeding programs. This proposal for a paradigm shift in model development was illustrated taking salt stress tolerance and rice as a case study. Dedicated growth chamber experiments were conducted to develop a new model explicitly accounting for tolerance traits modulating Na+ uptake and distribution in plant tissues, as well as the impact of the accumulated Na+ on photosynthesis, senescence and spikelet sterility. An ideotyping study was conducted at two sites (in Greece and California) characterized by different seasonal dynamics of salinity in field water. Results showed how, under different scenarios, traits assuring the largest contribution to the overall tolerance could refer to completely different physiological mechanisms: tissue tolerance in one case, sodium exclusion in the other. This encourages the development of explicit trait-based approaches to increase the integration of crop models within breeding programs.
A parallel path to achieve this goal is the development of modelling platforms targeting breeders as final users, who does not have necessarily in-depth skills in crop modelling and IT. The platform ISIde, derived from a close collaboration between target users, biophysical modelers and IT specialists, represents the first prototype of a platform specifically developed for being used directly by breeders to evaluate in silico improved varieties at district level.
This thesis demonstrated the usefulness of simulation models for the definition of ideotypes for specific agro-environmental conditions. Targeting ideotyping applications, new methodologies, paradigms for model development and modelling tools were developed, thus contributing to improve the potential of crop modelling to support breeding programs. Future developments will target researches aimed at overcoming the limits behind this study, i.e., (i) absence of explicit interactions between traits, (ii) no adaptation strategies considered, and (iii) lack of approaches for the simulation of the evolutionary potential of pathogens in response to long-term climate variations and increased host resistance.
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Gusman, Grasielle Soares. "Respostas fisiológicas e bioquímicas de Lactuca sativa cv Hanson submetida ao arsenato (AsV) e arsenito (AsIII)." Universidade Federal de Viçosa, 2011. http://locus.ufv.br/handle/123456789/4323.
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Previous issue date: 2011-02-21Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The inorganic forms of arsenic (As), arsenate (AsV) and arsenite (AsIII) are considered the most toxic as well as the most found in plants. As contamination in foods represents a great risk to the public health, since it is considered the second mainly way of contamination by this metalloid. Therefore, lettuce plants (Lactuca sativa cv Hanson) were exposed to different AsV and AsIII concentrations, 0.0, 6.6, 13.2, 26.4 and 52.8 μmol L-1 for three days. It was evaluated As accumulation and distribution in roots and leaves, and its effect on vegetal growth, gas exchange, fluorescence of chlorophyll a and chlorophylls and carotenoids concentration, as well as on mineral nutrition, evaluating the concentration of calcium (Ca), magnesium (Mg), phosphorus (P), iron (Fe), manganese (Mn) and copper (Cu) and the regulation of the antioxidant enzymatic system as superoxide dismutase (SOD), total peroxidases (POD), catalase (CAT), glutathione reductase (GR) and ascorbate peroxidase (APX). The tested plants accumulated significant amounts of As with the increment of AsV and AsIII concentration in the nutrient solution, in leaves and roots, observing higher accumulation in roots. This fact promoted reduction in gas exchange parameters as liquid photosynthesis (A), stomatal conductance (gS), transpiration (E) and effective use of water (EUW), except at 6.6 μmol L-1 AsV. The internal concentration of CO2 (Ci) increased at the highest AsV and AsIII concentrations, which indicated changes in the biochemical phase of photosynthesis. The parameters of fluorescence of chlorophyll a were changed with reduction on photochemical quenching (qP), electron transport rate (ETR), followed by the increment in non-photochemical quenching (NPQ), which showed a change in the photochemical phase of photosynthetic process. In consequence, plant growth was affected, except the roots of plants that were exposed to the concentration of 6.6 μmol L-1 AsV. The exposition of plants to AsV and AsIII resulted in increasing lipid peroxidation as observed by the increment in malonaldehyde (MDA), an indicator of the action of the oxidative stress. However, this oxidative stress was not able to affect tylacoid membrane and cloroplastic pigments concentration, chlorophylls and carotenoids, as observed by the unaltered minimal fluorescence (F0) and potential photochemical efficiency of photosystem II (Fv/Fm). The oxidative stress followed by the direct damages suffered by the roots, promoted changes in the mineral nutrition of leaves and roots. The concentration of nutrients involved with tolerance mechanisms, as Ca and Mg, were increased. The concentration of 6.6 μmol L-1, of both chemical forms promoted increment in phosphorus (P) concentration, not being this result observed at the highest concentrations of AsV and AsIII. The probably reactive oxygen species (ROS) produced, due to the exposition to AsV and AsIII promoted changes in the antioxidant enzymatic system. In the leaves, it was observed an increment in the activities of SOD, CAT, POX and APX, whereas in the roots, of SOD, CAT and GR, characterizing differentiated tolerance mechanism in leaves and roots.
As formas inorgânicas de arsênio (As), arsenato (AsV) e arsenito (AsIII) são consideradas as mais tóxicas sendo também, as mais encontradas em plantas. A contaminação de As em alimentos representa um grande risco à saúde pública, já que essa é considerada a segunda principal forma de contaminação por esse metalóide. Assim, plantas de alface (Lactuca sativa cv Hanson) foram expostas a diferentes concentrações de AsV e AsIII, 0,0; 6,6; 13,2; 26,4 e 52,8 μmol L-1, por três dias. Foram avaliados o acúmulo e a distribuição de As em raízes e folhas e o efeito no crescimento vegetal, nas trocas gasosas, na fluorescência da clorofila a e na concentração de clorofilas e carotenóides, assim como as alterações na nutrição mineral, avaliando-se a concentração de cálcio (Ca), magnésio (Mg), fósforo (P), ferro (Fe), manganês (Mn) e cobre (Cu) e a regulação das enzimas do sistema antioxidante, como dismutase do superóxido (SOD), peroxidases totais (POX), catalase (CAT), redutase da glutationa (GR) e peroxidase do ascorbato (APX). As plantas testadas acumularam quantidades significativas de As, à medida que se aumentou a concentração de AsV e AsIII na solução nutritiva, em folhas e raízes, observando-se maior acúmulo nas raízes. Tal fato, promoveu redução nos parâmetros de trocas gasosas como fotossíntese líquida (A), condutância estomática (gS), transpiração (E) e eficiência do uso da água (EUA), exceto para 6,6 μmol L-1 AsV. A concentração interna de CO2 (Ci) aumentou nas maiores concentrações de AsV e AsIII, indicando alteração na etapa bioquímica da fotossíntese. Os parâmetros de fluorescência da clorofila a foram alterados, com redução no coeficiente de extinção fotoquímico (qP) e transporte relativo de elétrons (ETR), acompanhados do aumento do coeficiente de extinção não-fotoquímico (NPQ), evidenciando alteração na etapa fotoquímica do processo fotossintético. Em consequência, o crescimento das plantas foi afetado, à exceção das raízes daquelas expostas à concentração de 6,6 μmol L-1 de AsV. A exposição das plantas ao AsV e AsIII resultou em peroxidação de lipídios crescente, conforme observado pelo aumento na concentração de malonaldeído (MDA), indicativo de ação do estresse oxidativo. Entretanto, esse estresse oxidativo não foi capaz de afetar as membranas dos tilacóides e a concentração dos pigmentos cloroplastídicos, clorofilas e carotenóides, conforme observado pela inalteração da fluorescência mínima (F0) e da eficiência fotoquímica potencial do fotossistema II (Fv/Fm). O estresse oxidativo, acompanhado dos danos diretos sofridos pelo sistema radicular, promoveu alterações na nutrição mineral de folhas e raízes. A concentração dos nutrientes envolvidos com mecanismos de tolerância, como Ca e Mg, foram aumentadas. A concentração 6,6 μmol L-1, de ambas as formas químicas promoveu aumento na concentração de fósforo (P), não sendo esse resultado observados nas concentrações superiores de AsV e AsIII. A provável produção de espécies reativas de oxigênio (ROS), decorrentes da exposição ao AsV e AsIII promoveu alteração no sistema enzimático antioxidante. Nas folhas, observou-se aumento nas atividades da SOD, CAT, POX e APX, enquanto, nas raízes, da SOD, CAT e GR, caracterizando mecanismo de tolerância diferenciado nas folhas e raízes.
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Davids, Danielle Andrea. "Physiological and molecular characterization of wheat cultivars to Fusarium oxysporum infection." University of the Western Cape, 2019. http://hdl.handle.net/11394/7708.
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>Magister Scientiae - MScBiotic stress is one of the main causes for agricultural loss of economically important cereal crops. The increasing prevalence of biotic stress inflicted by fungal species such as Fusarium has significantly reduced yields and quality of cereals, threatening sustainable agriculture and food security worldwide. Interactions between wheat and Fusarium spp. such as Fusarium oxysporum promotes the accumulation of reactive oxygen species (ROS). Overproduction of ROS can become toxic to plants depending on the scavenging ability of antioxidant systems to maintain redox homeostasis. This study investigated the effects of F. oxysporum on the physiological and biochemical response of three wheat cultivars namely, SST 056, SST 088 and SST 015. Physiological responses were monitored by measuring changes observed in plant growth parameters including shoot and root growth and biomass, relative water content as well as photosynthetic metabolism and osmolyte content in all three wheat cultivars. Downstream biochemical analysis involved monitoring the accumulation of ROS biomarkers (superoxide and hydrogen peroxide) as well as the detection of enzymatic activity of superoxide dismutase (SOD), ascorbate peroxidase (APX) and peroxidase (POD). These biochemical responses were only monitored on the two wheat cultivars which presented contrasting responses to F. oxysporum infection. Results showed that F. oxysporum significantly reduced plant growth, biomass, chlorophyll pigments and relative water content of all three cultivars, with the highest reduction observed for SST 088 relative to SST 015 and SST056. On the other hand, proline content was significantly enhanced in all three wheat cultivars, with the highest increase observed for SST 015 relative to SST 056 and SST 088. Based on the contrasting physiological results observed for these three cultivars, downstream biochemical analysis was focused on SST 015 and SST 088. F. oxysporum trigged an increased in superoxide and hydrogen peroxide contents in both cultivars, with the highest increase observed for SST 088. A similar trend was observed for the extent of lipid peroxidation, manifested as enhanced MDA levels. Furthermore, F. oxysporum differentially altered antioxidant enzyme activity relative to the control of both wheat cultivars. A Significant increase in SOD activity was observed for both cultivars in response to F. oxysporum. However, contrasting responses in APX and POD activity (as seen for the band intensities of individual isoforms) was observed in these wheat cultivars in response to F. oxysporum. Based on the results obtained in this study we suggest that F. oxysporum infection has varying degrees of severity in different wheat cultivars. In light of the significant reduction of plant development coupled with enhanced ROS accumulation and differential antioxidant capacity for SST 015 relative SST 088, we suggest that SST 015 is more resilient to F. oxysporum. We thus conclude that a direct relationship exists between ROS accumulation and antioxidant scavenging in regulating plant tolerance against F. oxysporum pathogens.
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Giannini, Maria Fernanda Colo. "The influence of phytoplankton pigments composition and dominant cell size on fluorescence-derived photophysiological parameters and implications for primary production rates." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/21/21134/tde-08122016-114954/.
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Phytoplankton chlorophyll-a fluorescence, measured in situ, can be applied as a tool to estimate primary production in the ocean over a large range of temporal and spatial scales. This non-invasive technique allows for fast assessments of photo-physiological parameters in contrast to the traditional methodologies (14C uptake and O2 evolution). The main photo-physiological parameters derived by the available instruments are yields, and as such, require careful interpretation. The comprehension of the main sources of variability of the photochemical and the light absorption efficiencies in marine phytoplankton has increased in the past years, largely by studies using monospecific cultures. In natural communities, however, the development of primary production models based on chlorophyll-a fluorescence remain limited as they are simultaneously subjected to a wide range of environmental and biological factors. This study will test the hypothesis that photo-physiological models for primary production estimates can be improved when key phytoplankton features, such as the pigments composition and dominant cell size, are taking into account. The approach was to contrast the photo-physiological parameters derived from measurements in distinct oceanographic regions, as well as those derived in a specific environment with presented different nutrient concentration according to the time of sampling. In addition, we showed for monospecific cultures, how the photo-physiological parameters are quantitatively related to the production of carbon under the interactive effects of taxonomic composition and cell size. The proportions of photosynthetic and photoprotective pigments present in the community were related to the bulk photochemical efficiency and the cross-section of light absorption, but varied among oceanographic regions and the depth of the water column. A parameterization of fluorescence-derived primary production rates, using four dominant size classes, was derived for natural phytoplankton communities under different nutrients conditions in a coastal environment, showing that the parameters differed among size classes above a threshold of nutrient concentration. The direct conversion rates between fluorescence-derived primary production and carbon assimilation rates, computed for two distinct phytoplankton cell sizes grown in controlled laboratorial conditions, showed that cell size strongly influences the efficiency of light absorption and photochemistry, however species-specific responses in photosynthetic energy allocation dominated the differences observed in how absorbed light is utilized to carbon assimilation, i.e., in the electron requirements for carbon assimilation. The results highlighted the importance of the tight coupling of nutrients availability and phytoplankton communities, as well as for measurements of chlorophyll-a fluorescence in the ocean and primary production models. This work presents a novel contribution to the increasing efforts to apply fluorescence-based techniques to understand and parameterize primary production estimates in marine systems, especially at highly dynamic environments.A fluorescência da clorofila-a do fitoplâncton, medida in situ, pode ser uma ferramenta para estimar produção primária no oceano em grande escala temporal e espacial. Esta técnica não-invasiva permite análises rápidas de parâmetros foto-fisiológicos ao contrário de metodologias tradicionais (assimilação de 14C e produção de O2). Os principais parâmetros foto-fisiológicos de instrumentos disponíveis hoje tratam-se de eficiências, e como tal, requerem cuidados em serem interpretados. A compreensão das principais fontes de variabilidade da eficiência fotoquímica e de absorção de luz no fitoplâncton marinho tem aumentado nos últimos anos, em sua maioria em cultivos monoespecíficos. Em comunidades naturais, entretanto, o desenvolvimento de modelos de produção primária baseados na fluorescência da clorofila-a ainda é limitado uma vez que estão sujeitos à uma ampla gama de fatores ambientais e biológicos. Esse estudo testa a hipótese de que modelos foto-fisiológicos para estimar produção primária podem ser aprimorados considerando-se características fundamentais do fitoplâncton, como a composição de pigmentos e tamanho celular dominante. A estratégia foi contrastar parâmetros foto-fisiológicos derivados de medidas em regiões oceanográficas distintas, assim como medidas em um ambiente específico com diferentes concentrações de nutrientes ao longo do período amostrado. Adicionalmente, apresentamos através de cultivos monoespecíficos, como parâmetros foto-fisiológicos são quantitativamente relacionados à produção de carbono e os efeitos interativos da composição taxonômica e tamanho celular nessa relação. A proporção de pigmentos fotossintéticos e fotoprotetores da comunidade foram relacionados à eficiência fotoquímica e seção transversal de absorção de luz, porém variaram de acordo com a região oceanográfica e profundidade na coluna d\'água. Uma parameterização de taxas de produção primária derivadas da fluorescência, usando quatro classes de tamanho dominantes, foi proposta para comunidades naturais de fitoplâncton sob condições de nutrientes diferentes em um ambiente costeiro, mostrando que os parâmetros diferiram entre as classes de tamanho acima de um limiar de concentração de nutrientes. As taxas de conversão diretas entre produção primária derivada da fluorescência e taxas de assimilação de carbono, computadas para dois tamanhos de fitoplâncton crescidos em condições controladas em laboratório, mostraram que tamanho celular influencia as eficiências de absorção de luz e fotoquímica, porém respostas espécie-específicas na alocação de energia fotossintética dominaram as diferenças observadas em como a luz absorvida é utilizada para assimilação de carbono, ou seja, na razão de elétrons exigidos para assimilação de carbono. Os resultados destacam a importância do acoplamento da disponibilidade de nutrientes com a comunidade fitoplanctônica, assim como das medidas de fluorescência da clorofila-a no oceano e nos modelos de produção primária. Este trabalho apresenta uma contribuição inédita nos esforços crescentes em aplicar técnicas baseadas na fluorescência para entender e parameterizar estimativas de produção primária nos sistemas marinhos, especialmente em ambientes altamente dinâmicos.
Books on the topic "Photosynthetic parameter"
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Msuya, Flower E. The performance of the seaweeds ulva reticulata and chaetomorpha crassa as biofilters in land based intergrated mariculture: Nutritional parameters and photosynthesis. [Zanzibar]: Western Indian Ocean Marine Sciences Association, 2004.
Find full textBook chapters on the topic "Photosynthetic parameter"
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Váradi, Gy, B. Bálo, E. Papp, B. Böddi, and D. Polyák. "Photosynthetic Parameters of Virus Infected Grapevine Leaves." In Photosynthesis: from Light to Biosphere, 3881–84. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-0173-5_915.
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Bhattacharjee, S. K. "Sensitivity to Far-uv Light as a Parameter for the Study of in vivo Regulation of Development of PSII Particles in Cyanobacteria: An Analytical Model." In Photosynthesis, 269–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74221-7_21.
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Buschmann, C., and H. Prehn. "Photosynthetic Parameters as Measured via Non-Radiative De-Excitation." In Biological Control of Photosynthesis, 83–91. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4384-1_7.
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Muschak, Michael, Lothar Willmitzer, and Joachim Fisahn. "Gas Exchange and Environmental Parameters at FBPase Antisense Potatoes." In Photosynthesis: Mechanisms and Effects, 3475–78. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_811.
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Ronen, R., O. Canaani, J. Garty, D. Cahen, S. Malkin, and M. Galun. "Photosynthetic Parameters in Ramalina Duriaei, in Vivo, Studied by Photoacoustics." In Lichen Physiology and Cell Biology, 9–22. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2527-7_2.
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Sarić, M. R., Ž. S. Stanković, and B. Krstić. "Relationship between Certain Photosynthetic Parameters and Yield in Different Wheat Cultivars." In Progress in Photosynthesis Research, 395–98. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-017-0519-6_80.
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Mallardi, Antonia, Mauro Giustini, Ruggero Angelico, and Gerardo Palazzo. "Thermodynamic Parameters of Quinone Binding to Bacterial Reaction Centers in Reverse Micelles." In Photosynthesis: Mechanisms and Effects, 889–92. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_210.
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Vidal, D., M. A. Miranda, F. Rodriguez, and E. Simon. "The Effects of Diclofop-Methyl and Methabenzthiazuron on Photosynthetic Parameters in Vicia faba." In Current Research in Photosynthesis, 3575–78. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0511-5_807.
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Castrillo, M., D. Fernández, A. M. Calcagno, and I. Trujillo. "Responses of Some Photosyntetic Parameters in C3 and C4 Crop Plants Under Water Deficit." In Current Research in Photosynthesis, 3507–10. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0511-5_790.
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Naber, J. Dirk, and Jack J. S. van Rensen. "Determination of the Exchange Parameters of Herbicides on the QB-Protein of Photosystem II." In Progress in Photosynthesis Research, 767–70. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-017-0516-5_160.
Full textConference papers on the topic "Photosynthetic parameter"
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Vilfan, Nastassia, Christiaan van der Tal, Peiqi Yang, and Wouter Verhoef. "Retrieving Photosynthetic Capacity Parameter from Leaf Photochemical Reflectance and Chlorophyll Fluorescence." In IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2018. http://dx.doi.org/10.1109/igarss.2018.8517912.
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Sakshaug, Egil. "Variability in photosynthetic parameters." In High Latitude Optics, edited by Hans-Christian Eilertsen. SPIE, 1993. http://dx.doi.org/10.1117/12.165490.
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ПИГАРЕВА, Светлана, Svetlana PIGAREVA, Наталья Зайцева, Natalya Zaitseva, Татьяна ЯГОВЕНКО, and Tat'yana YaGOVENKO. "EFFECT OF THE FUNGICIDE AMISTAR EXTRA ON A NUMBER OF BIOCHEMICAL INDICATORS OF YELLOW LUPIN PLANTS." In Multifunctional adaptive feed production. ru: Federal Williams Research Center of Forage Production and Agroecology, 2019. http://dx.doi.org/10.33814/mak-2019-21-69-40-44.
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The positive impact of fungicide Amistar extra on a number of physiological parameters is shown. Assimilation surface describes a level of photosynthetic potential and netto prod-uctivity of photosynthesis which increased in 1.07 and 1.09 times. Fungicide impact on nitrogen accumulation and dry matter in a plant was set. Decreasing of the total amount of plant pods was recorded. The treatment increased protein content in seeds of var. Prestizh. Tendency for increasing of alkaloid level in yellow lupin seeds and green mass was noticed.
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Kawano, Takeshi, Hirofumi Okano, Ai Yasuda, Kazuhiko Matsumoto, Ichio Asanuma, and Marlon R. Lewis. "Photosynthetic parameters in the western equatorial Pacific." In Second International Asia-Pacific Symposium on Remote Sensing of the Atmosphere, Environment, and Space, edited by Robert J. Frouin, Hiroshi Kawamura, and Motoaki Kishino. SPIE, 2001. http://dx.doi.org/10.1117/12.411676.
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VAGUSEVICIENĖ, Ilona, Sonata KAZLAUSKAITĖ, Aiste JUCHNEVICIENĖ, Asta BYLAITE, and Audrone ŽEBRAUSKIENĖ. "COMPARISON OF PHOTOSYNTHETIC PARAMETERS IN DIFFERENT WHEAT (TRITICUM AESTIVUM L.) VARIETIES." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.064.
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Dynamics of photosynthesis pigments in the leaves of different varieties of winter wheat during the vegetation period is analyzed in the paper. The accumulation of pigments in the plant depends on the physiological activity, growth and development of the plant, therefore the composition and content of photosynthesis pigments chlorophyll a, b and carotenoids reflect the general condition of the plant. The ratio of chlorophyll a / b for normal photosynthesis activity in the leaves of the plant should be at least 1:3. The object of the research is different varieties of winter wheat (Triticum aestivum L.) - 'Artist', 'Edvin', 'Skagen', 'Bertold' and 'Viola'. Field experiment was carried out at the Experimental Station of Aleksandras Stulginskis University in 2015-2016. Soil type was identified as IDg8 - k (LVg - p - w - cc) - shallow calcareous luvisol (Calc (ar) i - Epihypogleyic Luvisols). Agrochemical parameters of the soil were determined using accepted analytical methods. The content of photosynthesis pigments (chlorophyll a, b and carotenoids) in green leaf mass was determined in 96% ethyl alcohol extract applying spectrophotometric Wettstein method, “Genesys” 6 spectrophotometer. The photosynthesis productivity (Fpr) was calculated according to the formula: Fpr = 2 (M2-M1) / (L1 + L2) T. The accuracy of the data analysis was estimated according to the standard measurement deviation from the mean. The highest content of photosynthesis pigments has been accumulated by winter wheat variety 'Skagen'. The best result has been observed at the end of nodding stage. A lower content of photosynthesis pigments has been found in the leaves of 'Edvin', 'Viola' and 'Artist' varieties. The highest photosynthesis productivity of all winter wheat varieties has been recorded at the end of nodding stage, and decrease of photosynthesis productivity has been observed since milk maturity stage.
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Valenzuela, Ira C., Renann G. Baldovino, Argel A. Bandala, and Elmer P. Dadios. "Optimization of Photosynthetic Rate Parameters using Adaptive Neuro-Fuzzy Inference System (ANFIS)." In 2017 International Conference on Computer and Applications (ICCA). IEEE, 2017. http://dx.doi.org/10.1109/comapp.2017.8079734.
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Chen, Lea-Der. "Radiative Transport and Hydrodynamic Modeling of Microalgae Photosynthesis in Bio-Flow Reactors." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87116.
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A simplified two-phase flow PCH (physicochemical hydrodynamics) model is developed for modelling and simulation of microalgae growth in bio-flow reactor. The model considers carbon balance through coupled gas-phase and liquid-phase transport equations. The transport model accounts for interfacial transport of CO2 from gas bubble/slug to liquid, and microalgae photosynthesis reactions. A simplified photosynthesis reaction is adopted in the model, which assumes a pseudo-first order reaction for glucose pathway. The reaction rate is calculated assuming that it is proportional to the solar absorption rate by microalgae in the liquid. The reaction model also includes a simplified photoinhibition sub-model which assumes that the rate of photoinhibition is proportional to the square-root of solar irradiation reaching the algae cell. The Beer-Lambert law is used to calculate the radiative transfer of solar flux in seeded microalgae liquid flow. Analytical solution was obtained for single-channel bio-flow reactor. Decrease of the CO2 concentration in gas bubble/slug and in liquid flow is assumed to be the result of the microalgae growth in bio-flow reactor. Two efficiency parameters are defined: CO2 conversion efficiency and photosynthesis efficiency. The conversion efficiency is calculated based on the decrease of CO2 between the bio-flow reactor inlet and exit. The photosynthesis efficiency is based upon the heating value of microalgae yield versus solar irradiation. The rate of microalgae yield is calculated by multiplying the mass stoichiometric coefficient of photosynthesis reaction to CO2 consumption rate. Model analysis provided some insight of the microalgae formation in bio-flow reactor as interpreted from the PCH-coupled photosynthesis model that includes a dimensionless number as a potential scaling parameter for gas-phase only CO2 supply operation; photosynthesis efficiency increases with increasing CO2 molar concentration (i.e., number of moles per unit volume) at the reactor inlet for both gas-phase and liquid-phase only CO2 supply; an optimal irradiation flux for maximum photosynthesis efficiency — a factor to consider should artificial light source be used for harvesting algae.
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Danilova, E. D., L. V. Коlomeichuk, and M. V. Efimova. "Influence of chloride salinity on primary photosynthetic processes in potato leaves." In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.056.
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Mikhailova, T. A., O. V. Kalugina, O. V. Shergina, and L. V. Afanasieva. "ALTERATION OF PHOTOSYNTHESIS PARAMETERS IN SCOTS PINE UNDER ANTHROPOGENIC INFLUENCE." In The All-Russian Scientific Conference with International Participation and Schools of Young Scientists "Mechanisms of resistance of plants and microorganisms to unfavorable environmental". SIPPB SB RAS, 2018. http://dx.doi.org/10.31255/978-5-94797-319-8-1094-1098.
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Babin, Marcel, Nora Sadoadi, Luigi Lazzara, Jacques Gostan, Frederic Partensky, Annick Bricaud, Marcel Veldhuis, Andre Morel, and Paul G. Falkowski. "Photoacclimation strategy of Prochlorococcus sp. and consequences on large scale variations of photosynthetic parameters." In Ocean Optics XIII, edited by Steven G. Ackleson and Robert J. Frouin. SPIE, 1997. http://dx.doi.org/10.1117/12.266462.
Full textReports on the topic "Photosynthetic parameter"
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Hochman, Ayala, Thomas Nash III, and Pamela Padgett. Physiological and Biochemical Characterization of the Effects of Oxidant Air Pollutants, Ozone and Gas-phase Nitric Acid, on Plants and Lichens for their Use as Early Warning Biomonitors of these Air Pollutants. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7697115.bard.
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Introduction. Ozone and related oxidants are regarded as the most important phytotoxic air pollutant in many parts of the western world. A previously unrecognized component of smog, nitric acid, may have even greater deleterious effects on plants either by itself or by augmenting ozone injury. The effects of ozone on plants are well characterized with respect to structural and physiological changes, but very little is known about the biochemical changes in plants and lichens exposed to ozone and/or HNO3. Objectives.To compare and contrast the responses of crop plants and lichens to dry deposition of HNO3 and O3., separately, and combined in order to assess our working hypothesis that lichens respond to air pollution faster than plants. Lichens are most suitable for use as biomonitors because they offer a live-organism-based system that does not require maintenance and can be attached to any site, without the need for man-made technical support systems. Original Immediate aims To expose the tobacco (Nicotiana tabacum L.) cultivar Bel-W3 that is ozone supersensitive and the ozone sensitive red kidney bean (Phaseolusvulgaris) and the lichen Ramalinamenziesii to controlled HNO3 and O3 fumigations and combined and to follow the resulting structural, physiological and biochemical changes, with special reference to reactive oxygen species related parameters. Revised. Due to technical problems and time limitations we studied the lichen Ramalinamenziesii and two cultivar of tobacco: Bel-W3 that is ozone supersensitive and a resistant cultivar, which were exposed to HNO3 and O3 alone (not combined). Methodology. Plants and lichens were exposed in fumigation experiments to HNO3 and O3, in constantly stirred tank reactors and the resulting structural, physiological and biochemical changes were analyzed. Results. Lichens. Exposure of Ramalinamenziesiito HNO3 resulted in cell membrane damage that was evident by 14 days and continues to worsen by 28 days. Chlorophyll, photosynthesis and respiration all declined significantly in HNO3 treatments, with the toxic effects increasing with dosage. In contrast, O3 fumigations of R. menziesii showed no significant negative effects with no differences in the above response variables between high, moderate and low levels of fumigations. There was a gradual decrease in catalase activity with increased levels of HNO3. The activity of glutathione reductase dropped to 20% in thalli exposed to low HNO3 but increased with its increase. Glucose 6-phosphate dehydrogenase activity increase by 20% with low levels of the pollutants but decreased with its increase. Tobacco. After 3 weeks of exposure of the sensitive tobacco cultivar to ozone there were visible symptoms of toxicity, but no danmage was evident in the tolerant cultivar. Neither cultivar showed any visible symptoms after exposure to HNO3.In tobacco fumigated with O3, there was a significant decrease in maximum photosynthetic CO2 assimilation and stomatal conductance at high levels of the pollutant, while changes in mesophyll conductance were not significant. However, under HNO3 fumigation there was a significant increase in mesophyll conductance at low and high HNO3 levels while changes in maximum photosynthetic CO2 assimilation and stomatal conductance were not significant. We could not detect any activity of the antioxidant enzymes in the fumigated tobacco leaves. This is in spite of the fact that we were able to assay the enzymes in tobacco leaves grown in Israel. Conclusions. This project generated novel data, and potentially applicable to agriculture, on the differential response of lichens and tobacco to HNO3 and O3 pollutants. However, due to experimental problems and time limitation discussed in the body of the report, our data do not justify yet application for a full, 4-year grant. We hope that in the future we shall conduct more experiments related to our objectives, which will serve as a basis for a larger scale project to explore the possibility of using lichens and/or plants for biomonitoring of ozone and nitric acid air pollution.
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Paterson, Andrew H., Yehoshua Saranga, and Dan Yakir. Improving Productivity of Cotton (Gossypsum spp.) in Arid Region Agriculture: An Integrated Physiological/Genetic Approach. United States Department of Agriculture, December 1999. http://dx.doi.org/10.32747/1999.7573066.bard.
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Objectives: We seek to establish the basis for improving cotton productivity under arid conditions, by studying the water use efficiency - evaporative cooling interrelationship. Specifically, we will test the hypothesis that cotton productivity under arid conditions can be improved by combining high seasonal WUE with efficient evaporative cooling, evaluate whether high WUE and/or evaporative cooling are based on specific physiological factors such as diurnal flexibility in stomatal conductance, stomatal density, photosynthetic capacity, chlorophyll fluorescence, and plant water status. Genes influencing both WUE and evaporative cooling, as well as other parameters such as economic products (lint yield, quality, harvest index) of cotton will also be mapped, in order to evaluate influences of water relations on these parameters. Approach: Carbon isotope ratio will be used to evaluate WUE, accompanied by additional parameters to elucidate the relationship between WUE, evaporative cooling, and cotton productivity. A detailed RFLP map will be used to determine the number, location, and phenotypic effects of genes underlying genetic variation in WUE between cultivated cottons, as well as test associations of these genes with traits of economic importance such as harvest index, lint yield, and lint quality. Major Conclusions: Productivity and quality of cotton grown under well-watered versus water-limited conditions was shown to be partly accounted for by different quantitative trait loci (QTLs). Among a suite of physiological traits often found to differ between genotypes adapted to arid versus well-watered conditions, genetic mapping implicated only reduced plant osmotic potential in improved cotton productivity under arid conditions. Our findings clearly implicate OP as a major component of cotton adaptation to arid conditions. However, testing of further physiological hypotheses is clearly needed to account for additional QTL alleles conferring higher seed-cotton yield under arid conditions, such as three of the five we found. Near-isogenic lines being made for QTLs discovered herein will offer a powerful new tool useful toward identification of the underlying gene(s) by using fine-scale mapping approaches (Paterson et al 1990). Implications: Adaptation to both arid and favorable conditions can be combined into the same genotype. We have identified diagnostic DNA markers that are being applied to creation of such desirable genotypes. Simultaneous improvement of productivity (and/or quality) for both arid and irrigated conditions will require more extensive field testing and the manipulation of larger numbers of genes, reducing the expected rate of genetic gain These difficulties may be at least partly ameliorated by efficiencies gained through identification and use of diagnostic DNA markers. Genomic tools and approaches may expedite adaptation of crops to arid cultivation, help to test roles of additional physiological factors, and guide the isolation of the underlying genes that protect crop performance under arid conditions.
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Ohad, Itzhak, and Himadri Pakrasi. Role of Cytochrome B559 in Photoinhibition. United States Department of Agriculture, December 1995. http://dx.doi.org/10.32747/1995.7613031.bard.
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The aim of this research project was to obtain information on the role of the cytochrome b559 in the function of Photosystem-II (PSII) with special emphasis on the light induced photo inactivation of PSII and turnover of the photochemical reaction center II protein subunit RCII-D1. The major goals of this project were: 1) Isolation and sequencing of the Chlamydomonas chloroplast psbE and psbF genes encoding the cytochrome b559 a and b subunits respectively; 2) Generation of site directed mutants and testing the effect of such mutation on the function of PSII under various light conditions; 3) To obtain further information on the mechanism of the light induced degradation and replacement of the PSII core proteins. This information shall serve as a basis for the understanding of the role of the cytochrome b559 in the process of photoinhibition and recovery of photosynthetic activity as well as during low light induced turnover of the D1 protein. Unlike in other organisms in which the psbE and psbF genes encoding the a and b subunits of cytochrome b559, are part of an operon which also includes the psbL and psbJ genes, in Chlamydomonas these genes are transcribed from different regions of the chloroplast chromosome. The charge distribution of the derived amino-acid sequences of psbE and psbF gene products differs from that of the corresponding genes in other organisms as far as the rule of "positive charge in" is concerned relative to the process of the polypeptide insertion in the thylakoid membrane. However, the sum of the charges of both subunits corresponds to the above rule possibly indicating co-insertion of both subunits in the process of cytochrome b559 assembly. A plasmid designed for the introduction of site-specific mutations into the psbF gene of C. reinhardtii. was constructed. The vector consists of a DNA fragment from the chromosome of C. reinhardtii which spans the region of the psbF gene, upstream of which the spectinomycin-resistance-conferring aadA cassette was inserted. This vector was successfully used to transform wild type C. reinhardtii cells. The spectinomycin resistant strain thus obtained can grow autotrophically and does not show significant changes as compared to the wild-type strain in PSII activity. The following mutations have been introduced in the psbF gene: H23M; H23Y; W19L and W19. The replacement of H23 involved in the heme binding to M and Y was meant to permit heme binding but eventually alter some or all of the electron transport properties of the mutated cytochrome. Tryptophane W19, a strictly conserved residue, is proximal to the heme and may interact with the tetrapyrole ring. Therefore its replacement may effect the heme properties. A change to tyrosine may have a lesser affect on the potential or electron transfer rate while a replacement of W19 by leucine is meant to introduce a more prominent disturbance in these parameters. Two of the mutants, FW19L and FH23M have segregated already and are homoplasmic. The rest are still grown under selection conditions until complete segregation will be obtained. All mutants contain assembled and functional PSII exhibiting an increased sensitivity of PSII to the light. Work is still in progress for the detailed characterization of the mutants PSII properties. A tobacco mutant, S6, obtained by Maliga and coworkers harboring the F26S mutation in the b subunit was made available to us and was characterized. Measurements of PSII charge separation and recombination, polypeptide content and electron flow indicates that this mutation indeed results in light sensitivity. Presently further work is in progress in the detailed characterization of the properties of all the above mutants. Information was obtained demonstrating that photoinactivation of PSII in vivo initiates a series of progressive changes in the properties of RCII which result in an irreversible modification of the RCII-D1 protein leading to its degradation and replacement. The cleavage process of the modified RCII-D1 protein is regulated by the occupancy of the QB site of RCII by plastoquinone. Newly synthesized D1 protein is not accumulated in a stable form unless integrated in reassembled RCII. Thus the degradation of the irreversibly modified RCII-D1 protein is essential for the recovery process. The light induced degradation of the RCII-D1 protein is rapid in mutants lacking the pD1 processing protease such as in the LF-1 mutant of the unicellular alga Scenedesmus obliquus. In this case the Mn binding site of PSII is abolished, the water oxidation process is inhibited and harmful cation radicals are formed following light induced electron flow in PSII. In such mutants photo-inactivation of PSII is rapid, it is not protected by ligands binding at the QB site and the degradation of the inactivated RCII-D1 occurs rapidly also in the dark. Furthermore the degraded D1 protein can be replaced in the dark in absence of light driven redox controlled reactions. The replacement of the RCII-D1 protein involves the de novo synthesis of the precursor protein, pD1, and its processing at the C-terminus end by an unknown processing protease. In the frame of this work, a gene previously isolated and sequenced by Dr. Pakrasi's group has been identified as encoding the RCII-pD1 C-terminus processing protease in the cyanobacterium Synechocystis sp. PCC 6803. The deduced sequence of the ctpA protein shows significant similarity to the bovine, human and insect interphotoreceptor retinoid-binding proteins. Results obtained using C. reinhardtii cells exposes to low light or series of single turnover light flashes have been also obtained indicating that the process of RCII-D1 protein turnover under non-photoinactivating conditions (low light) may be related to charge recombination in RCII due to back electron flow from the semiquinone QB- to the oxidised S2,3 states of the Mn cluster involved in the water oxidation process.