Journal articles on the topic 'Laser-Induced Chlorophyll Fluorescence'

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1

Wan Wen-Bo, Hua Deng-Xin, Le Jing, Liu Mei-Xia, and Cao Ning. "Laser-induced chlorophyll fluorescence lifetime measurement and characteristic analysis." Acta Physica Sinica 62, no. 19 (2013): 190601. http://dx.doi.org/10.7498/aps.62.190601.

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2

Rosema, A., J. F. H. Snel, H. Zahn, W. F. Buurmeijer, and L. W. A. Van Hove. "The Relation between Laser-Induced Chlorophyll Fluorescence and Photosynthesis." Remote Sensing of Environment 65, no. 2 (August 1998): 143–54. http://dx.doi.org/10.1016/s0034-4257(98)00020-0.

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3

Bunkin, Alexey F., Sergey M. Pershin, Diana G. Artemova, Sergey V. Gudkov, Alexey V. Gomankov, Pavel A. Sdvizhenskii, Mikhail Ya Grishin, and Vasily N. Lednev. "Fossil Plant Remains Diagnostics by Laser-Induced Fluorescence and Raman Spectroscopies." Photonics 10, no. 1 (December 24, 2022): 15. http://dx.doi.org/10.3390/photonics10010015.

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Fossilized plant remains have been studied simultaneously by laser induced fluorescence and Raman spectroscopies, to reveal the prospective methods for onsite or/and laser remote sensing in future extraterrestrial missions. A multiwavelength instrument, capable of fluorescence and Raman measurements, has been utilized for the study of isolated plant fossils, as well as fossils associated with sedimentary rocks. Laser-induced fluorescence spectroscopy revealed that plant fossils and rocks’ luminosity differed significantly due to chlorophyll derivatives (chlorin, porphyrins, lignin components etc.); therefore, fossilized plants can be easily detected at rock surfaces onsite. Raman spectroscopy highly altered the fossilized graphitic material via the carbon D and G bands. Our results demonstrated that combined laser-induced fluorescence and Raman spectroscopy measurements can provide new insights into the detection of samples with biogenicity indicators such as chlorophyll and its derivatives, as well as kerogenous materials. The prospects of multiwavelength LIDAR instrument studies under fieldwork conditions are discussed for fossils diagnostics. The method of laser remote sensing can be useful in geological exploration in the search for oil, coal-bearing rocks, and rocks with a high content of organic matter.
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4

ZORO-DIAMA, Emma Georgina, Adama Penetjiligue SORO, Kedro Siriki DIOMANDE, Kouadio DIAN, Amara KAMATE, and Adjo Viviane ADOHI-KROU. "Water Deficiency Detection of Hevea brasiliensis Clones by Laser Induced Fluorescence." Applied Physics Research 9, no. 5 (August 22, 2017): 36. http://dx.doi.org/10.5539/apr.v9n5p36.

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Water is the key nutritional element for the optimal development of plants. A water deficiency leads to lower crop productivity. As the health status of a plant influences the photosynthesis process, a photosynthetic diagnosis of a plant can be carried by laser induced chlorophyll fluorescence, a reliable and fast method that is non-destructive to the sample. In this study, we show that it is possible to detect the water deficiency of rubber tree hevea brasiliensis from the chlorophyll fluorescence ratio. The fluorescence ratio used in this study is called the effective ratio and it corresponds to the both fluorescence peaks ratio. We noticed that the water deficient plants fluorescence ratios were higher than those of normally watered plants. Moreover, the stressed plants' ratios are greater than a threshold value which depends on the duration of water deprivation application.
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5

Saleem, M., Babar Manzoor Atta, Zulfiqar Ali, and M. Bilal. "Laser-induced fluorescence spectroscopy for early disease detection in grapefruit plants." Photochemical & Photobiological Sciences 19, no. 5 (2020): 713–21. http://dx.doi.org/10.1039/c9pp00368a.

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6

WAN Wen-bo, 万文博, and 苏俊宏 SU Jun-hong. "Laser-induced Plant Chlorophyll Fluorescence Lifetime and Spectral Properties Analysis." ACTA PHOTONICA SINICA 47, no. 6 (2018): 630001. http://dx.doi.org/10.3788/gzxb20184706.0630001.

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7

Kiewnick, Sebastian, Walter Kühbauch, Astrid Schmitz, Iryna Tartachnyk, and Richard Sikora. "Detection of Heterodera schachtii infestation in sugar beet by means of laser-induced and pulse amplitude modulated chlorophyll fluorescence." Nematology 8, no. 2 (2006): 273–86. http://dx.doi.org/10.1163/156854106777998755.

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AbstractTwo glasshouse experiments with sugar beet cvs Penta and Macarena inoculated, respectively, with 0 or 1500 and 0, 500, 1000 or 1500 juveniles of Heterodera schachtii, were conducted to estimate the capability of laser-induced chlorophyll fluorescence (LIF) and pulse amplitude modulated (PAM) chlorophyll fluorescence techniques to detect H. schachtii infestation and to differentiate between infestation levels. Fluorescence and gas exchange parameters, nitrogen and chlorophyll content of sugar beet leaves were measured weekly after nematode inoculation. Sugar beet plants responded to H. schachtii infestation initially with a decrease in photosynthesis rate and later with a reduction in nitrogen uptake and chlorophyll concentration. At the early stages of nematode infestation, before visual symptoms were evident, infested sugar beet plants displayed increased fluorescence (F680, F740). Later stages of infection were accompanied by an increase in the F686/F740 ratio, ground fluorescence (Fo) and a decrease in photochemical efficiency (Fv/Fm) induced by degradation of leaf chlorophyll. Sugar beet plants infested with 500, 1000 or 1500 juveniles per 100 cm3 of soil did not differ either in their nitrogen and chlorophyll content or in photosynthesis and transpiration rate. The linear discrimination analysis based on the combination of PAM and LIF parameters resulted in 100% correct classification of control plants and high classification rates (60-100%) of the infested treatments on all the sampling dates. Whether the fluorescence technique will differentiate nematode densities under field conditions needs further study.
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8

Pandey, Jitendra Kumar, and R. Gopal. "Laser-induced chlorophyll fluorescence and reflectance spectroscopy of cadmium treatedTriticum aestivumL. plants." Spectroscopy 26, no. 2 (2011): 129–39. http://dx.doi.org/10.1155/2011/640232.

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The present study deals with laser-induced chlorophyll fluorescence (LICF) spectra, reflectance spectra and fluorescence induction kinetics (FIK) curves ofTriticum aestivumL. plants treated with different concentrations of cadmium (0.01, 0.1 and 1.0 mM). LICF spectra were recorded in the region of 650–780 nm using violet diode laser (405 nm) and FIK curves were recorded at 685 and 730 nm using red diode laser (635 nm) for excitation. Reflectance spectra were recorded in the region of 400–800 nm using spectrophotometer with an integrating sphere. The fluorescence intensity ratios (FIR) were determined from LICF spectra, vitality index (Rfd) from FIK curves and narrow band vegetation index (NBVI) from reflectance spectra. These parameters along with plant growth parameters and photosynthetic pigment contents were used to analyze the effect of cadmium on wheat plants. The results clearly show that lower concentration of Cd (0.01 mM) shows stimulatory response; whereas higher concentrations (0.1 and 1.0 Mm) are hazardous for plant growth, photosynthetic pigments and photosynthetic activity of wheat plants.
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9

Pingree, R. D., and R. P. Harris. "An in vivo fluorescence response in the Bay of Biscay in June." Journal of the Marine Biological Association of the United Kingdom 68, no. 3 (August 1988): 519–29. http://dx.doi.org/10.1017/s002531540004337x.

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CONCLUSION AND SUMMARYSurface fluorescence measurements in June in the Bay of Biscay showed little correlation with chlorophyll a measurements due to the presence of a marked diurnal fluorescence rhythm although satisfactory correlations have been obtained at other times of year in the same region (see Fig. 10 of Pingree et al. 1982). By contrast, the beam attenuation coefficient values showed a good correlation with the chlorophyll a measurements and can be used to map the sea surface distribution of chlorophyll a when the diurnal rhythm is present, particularly when the phytoplankton is dominated by a single species. This conclusion may be of considerable practical significance when contemplating synoptic surveys in such situations. As Prezlin & Ley (1980) have observed there is growing awareness that fluorescence per unit chlorophyll a is not a constant that can be used reliably in mixed phytoplankton biomass estimates based on in vivo chlorophyll a fluorescence, and the problem is clearly compounded if some species exhibit a marked diurnal fluorescence rhythm. Furthermore, the present observations support the caveats of Falkowski & Kiefer (1985), that in situ moored fluorometers, the use of air-borne laser-induced fluorescence, or satellite-received passive, solar-induced fluorescence, only measure fluorescence, not chlorophyll per se.The fluorescence response near the shelf-break over a 24 h period following a drogued dahn buoy showed a variation of about a factor of 5 between the day and night fluorescence levels. Beam attenuation coefficient measurements and Coulter Counter analyses showed that these results could not be attributed to the migration of the phytoplankton.
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10

Sailaja, M. V., Y. Chandrasekhar, D. Narayana Rao, and V. S. Rama Das. "Laser-induced Chlorophyll Fluorescence Ratio in Certain Plants Exhibiting Leaf Heliotropism." Functional Plant Biology 24, no. 2 (1997): 159. http://dx.doi.org/10.1071/pp96027.

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Laser-induced F685/F720 chlorophyll fluorescence of intact leaves in solar tracking plants from Euphorbiaceae (Ricinus communis L.), Amaranthaceae (Amaranthus gangeticus L., Amaranthus viridis L.), Malvaceae (Hibiscus cannabinus L., Althaea rosea L.), Fabaceae (Dolichos lablab L.) Capparadaceae (Cleome gynandra L.) exhibited remarkable diurnal constancy in contrast to those of compass plants from Poaceae (Oryza sativa L.) and Amaranthaceae (Telanthera ficoides Moq.) with fixed leaf orientation. The F685/F720 ratio remained constant in both the diaheliotropic and paraheliotropic plants, but it decreased during midday in compass plants. The acquired spectra were analysed in terms of Gaussian parameters to determine the relative intensity of contribution of various bands; the data suggested a decrease in both the F685 and the F720 bands at 1230 h in compass plants while they remained unaltered in reorienting leaves. The typical midday depression in F685/F720 ratio observed in compass plants may be due to down-regulation of both photosystems, I and II. This unique behaviour of diurnal constancy in laser-induced F685/F720 suggests that the leaves of diaheliotropic plants maximise light-use efficiency throughout the day and avoid the hazard of midday depression of photosynthesis.
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11

Sailaja, M. V., Y. Chandrasekhar, D. Narayana Rao, and V. S. Rama Das. "Laser-induced Chlorophyll Fluorescence Ratio in Certain Plants Exhibiting Leaf Heliotropism." Functional Plant Biology 24, no. 3 (1997): 407. http://dx.doi.org/10.1071/pp96027_co.

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Laser-induced F685/F720 chlorophyll fluorescence of intact leaves in solar tracking plants from Euphorbiaceae (Ricinus communis L.), Amaranthaceae (Amaranthus gangeticus L., Amaranthus viridis L.), Malvaceae (Hibiscus cannabinus L., Althaea rosea L.), Fabaceae (Dolichos lablab L.) Capparadaceae (Cleome gynandra L.) exhibited remarkable diurnal constancy in contrast to those of compass plants from Poaceae (Oryza sativa L.) and Amaranthaceae (Telanthera ficoides Moq.) with fixed leaf orientation. The F685/F720 ratio remained constant in both the diaheliotropic and paraheliotropic plants, but it decreased during midday in compass plants. The acquired spectra were analysed in terms of Gaussian parameters to determine the relative intensity of contribution of various bands; the data suggested a decrease in both the F685 and the F720 bands at 1230 h in compass plants while they remained unaltered in reorienting leaves. The typical midday depression in F685/F720 ratio observed in compass plants may be due to down-regulation of both photosystems, I and II. This unique behaviour of diurnal constancy in laser-induced F685/F720 suggests that the leaves of diaheliotropic plants maximise light-use efficiency throughout the day and avoid the hazard of midday depression of photosynthesis.
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12

Wan Wen-Bo, Hua Deng-Xin, Le Jing, Yan Zhe, and Zhou Chun-Yan. "Study of plant fluorescence properties based on laser-induced chlorophyll fluorescence lifetime imaging technology." Acta Physica Sinica 64, no. 19 (2015): 190702. http://dx.doi.org/10.7498/aps.64.190702.

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13

Wan, Wenbo, Dengxin Hua, Jing Le, Tingyao He, Zhe Yan, and Chunyan Zhou. "Study of laser-induced chlorophyll fluorescence lifetime measurement and its correction." Measurement 60 (January 2015): 64–70. http://dx.doi.org/10.1016/j.measurement.2014.09.070.

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14

SORO, Adama Penetjiligue, Emma Georgina ZORO-DIAMA, Kedro Sidiki DIOMANDE, Guy Euloge BANY, Yvon BIBILA MAYAYA BISSEYOU, and Adjo Viviane ADOHI-KROU. "Characterization of Water and Nitrogen Stress of Maize by Laser Induced Fluorescence." Applied Physics Research 8, no. 4 (July 30, 2016): 64. http://dx.doi.org/10.5539/apr.v8n4p64.

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<p class="1Body">Water and nitrogen are essential for the optimal development of corn plants. A deficiency of these elements leads to lower crop production. Also, the health status of a plant influences the photosynthesis process. The photosynthetic diagnosis of a plant from the chlorophyll fluorescence spectrum induced by laser is non-destructive to the sample, reliable and fast method. As part of this work, we showed that it is possible to detect the nitrogen and water deficiencies of corn from the chlorophyll fluorescence ratio at 690 nm and 740 nm, when the measurements are performed before the senescence phase.</p><p class="1Body">Indeed, we found that the R fluorescence ratio increases over time, for any stress on the plant. However, R decreases with the nitrogen stress and increases with increasing water loss.</p><p class="1Body">The measures should be performed 51 Days After Planting (DAP) to detect water deficiency and the suitable date for nitrogen deficiency detection is 61 DAP.</p><p class="1Body">Before each of these dates, the plants will be considered water deficient if the fluorescence ratio R ≤ 1.34 and will be nitrogen stressed if R &gt; 1.36.</p>
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15

Jian, Yang, Du Lin, Gong Wei, Sun Jia, Shi Shuo, and Chen Biwu. "Application of the chlorophyll fluorescence ratio in evaluation of paddy rice nitrogen status." Plant, Soil and Environment 63, No. 9 (September 26, 2017): 396–401. http://dx.doi.org/10.17221/460/2017-pse.

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In this research, laser-induced fluorescence (LIF) technique combined with back-propagation neural network (BPNN) was employed to analyse different nitrogen (N) fertilization levels in paddy rice. Leaf fluorescence characteristics (FLCs) were measured by using the LIF system built in our laboratory and exhibited different FLCs with different nitrogen fertilization levels. The correlation between fluorescence intensity ratios (F685/F460, F735/F460 and F735/F685) and the dose of N fertilization was established and analysed. Then, the BPNN algorithm was utilized to validate that the different N fertilization levels can be classified based on the three FLCs. The overall identification accuracies of 2014 and 2015 were 90% and 92.5%, respectively. Experimental results demonstrated that the three FLCs with the help of multivariate analysis can be served as a helpful tool in the evaluation of paddy rice N fertilization levels. Besides, this study can also provide guidance for the selection of LIF Lidar channels in the following research.
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16

NAKASHIMA, Taiken, Yuji YASUKOCHI, Shoji YAMASHITA, Takuya ARAKI, and Osamu UENO. "Laser-Induced Chlorophyll Fluorescence Measurement System to Assess Photosynthetic Status within Leaves." Environment Control in Biology 50, no. 2 (2012): 91–100. http://dx.doi.org/10.2525/ecb.50.91.

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17

Yang, Jian, Lin Du, Wei Gong, Shuo Shi, Jia Sun, and Biwu Chen. "Correcting the effect of the detection angular on laser-induced chlorophyll fluorescence." Journal of Physics Communications 4, no. 1 (January 27, 2020): 015017. http://dx.doi.org/10.1088/2399-6528/ab656f.

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18

Denison, R. Ford, and Raymond Russotti. "Field estimates of green leaf area index using laser-induced chlorophyll fluorescence." Field Crops Research 52, no. 1-2 (May 1997): 143–49. http://dx.doi.org/10.1016/s0378-4290(96)01064-7.

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19

Thoren, Doreen, Peter Thoren, and Urs Schmidhalter. "Influence of ambient light and temperature on laser-induced chlorophyll fluorescence measurements." European Journal of Agronomy 32, no. 2 (February 2010): 169–76. http://dx.doi.org/10.1016/j.eja.2009.10.003.

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20

Pandey, Jitendra Kumar, Preeti Srivastava, Ram Singh Yadav, and Ram Gopal. "Chlorophyll Fluorescence Spectra as an Indicator of X-Ray+EMS-Induced Phytotoxicity in Safflower." Spectroscopy: An International Journal 27 (2012): 207–14. http://dx.doi.org/10.1155/2012/951064.

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The present investigation deals with the study of in vivo laser-induced chlorophyll florescence spectra (LICF) of safflower leaves (Carthamus tinctoriusL.) for X-rays+EMS-treated plants. Seeds were treated with different doses of X-ray+EMS (5, 8, 12, 25, and 30 Kr+0.5% EMS) and were grown in the green house. The effects of the concerned treatment on chlorophyll (Chl) contents and Chl fluorescence were investigated after 7 days of germination. Results obtained revealed that the values of Chl contents, intensity of Chl fluorescence spectra, and fluorescence intensity ratio (FIR) F685/F730 are directly correlated with the treatment doses monitored. The treatment sets of 8, 12, and 25 Kr + 0.5% EMS doses showed an increase in FIR and thereby a decrease in the Chl contents. However, the lowest treatment dose of 5 Kr + 0.5% showed a decrease in FIR and thereby an increase in chlorophyll contents. Safflower seeds treated with 30 Kr + 0.5% EMS were proved to be lethal as they showed no germination. Thus, our study demonstrates early detection of chlorophyll damage caused by various physical and chemical mutagens through the application of LICF spectra.
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21

Thoren, Doreen, and Urs Schmidhalter. "Nitrogen status and biomass determination of oilseed rape by laser-induced chlorophyll fluorescence." European Journal of Agronomy 30, no. 3 (April 2009): 238–42. http://dx.doi.org/10.1016/j.eja.2008.12.001.

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22

Subhash, N., and C. N. Mohanan. "Laser-induced red chlorophyll fluorescence signatures as nutrient stress indicator in Rice Plants." Remote Sensing of Environment 47, no. 1 (January 1994): 45–50. http://dx.doi.org/10.1016/0034-4257(94)90126-0.

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23

Yang, Jian, Yinjia Cheng, Lin Du, Wei Gong, Shuo Shi, Jia Sun, and Biwu Chen. "Analyzing the effect of the incidence angle on chlorophyll fluorescence intensity based on laser-induced fluorescence lidar." Optics Express 27, no. 9 (April 18, 2019): 12541. http://dx.doi.org/10.1364/oe.27.012541.

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24

Lednev, Vasily N., Mikhail Ya Grishin, Pavel A. Sdvizhenskii, Rashid K. Kurbanov, Maksim A. Litvinov, Sergey V. Gudkov, and Sergey M. Pershin. "Fluorescence Mapping of Agricultural Fields Utilizing Drone-Based LIDAR." Photonics 9, no. 12 (December 10, 2022): 963. http://dx.doi.org/10.3390/photonics9120963.

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A compact and low-weight LIDAR instrument has been developed for laser-induced fluorescence spectroscopy sensing of maize fields. Fluorescence LIDAR had to be installed on a small industrial drone so that its mass was <2 kg and power consumption was <5 W. The LIDAR instrument utilized a continuous wave diode laser (405 nm, 150 mW) for inducing fluorescence and a small spectrometer for backscattered photons acquisition. For field testing, the LIDAR instrument was installed on a quadcopter for remote sensing of plants in a maize field in three periods of the plant’s life. The obtained fluorescence signal maps have demonstrated that the average chlorophyll content is rather non-uniform over the field and tends to increase through the plant vegetation cycle. Field tests proved the feasibility and perspectives of autonomous LIDAR sensing of agricultural fields from drones for the detection and location of plants under stress.
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25

Yamakawa, Shinzo. "Responses of Intact Leaf to Chemical Stresses Based on Laser-Induced Chlorophyll Fluorescence Induction." IEEJ Transactions on Electronics, Information and Systems 115, no. 12 (1995): 1438–43. http://dx.doi.org/10.1541/ieejeiss1987.115.12_1438.

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26

Hao, Tianyi, Yang Han, Ziying Li, Haiyan Yao, and Haofang Niu. "Estimating leaf chlorophyll content by laser-induced fluorescence technology at different viewing zenith angles." Applied Optics 59, no. 26 (September 3, 2020): 7734. http://dx.doi.org/10.1364/ao.400032.

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27

Utsunomiya, S., Y. Saito, Y. Kumagai, and T. Tomida. "Distribution Map of Plant Fluorescence Spectrum in Three-Dimensions Created by a Laser-Induced Fluorescence Spectrum (LIFS) Lidar Observations." EPJ Web of Conferences 237 (2020): 07012. http://dx.doi.org/10.1051/epjconf/202023707012.

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We have developed a vegetation monitoring lidar called a laser-induced fluorescence spectrum (LIFS) lidar which is able to get the living status of plants by observing their fluorescence remotely. The features of its operation are; daytime observations possible even outdoors, mobility and self-sufficiency, capability of mapping plant living information, and a user-friendly operation by unifying the controls of different equipment of the lidar using software. These features make observations by our LIFS lidar possible at any time and any place. In forest observations, we could depict three-dimensional structures of fluorescence spectrums. We also discuss in this work the possibility of monitoring other plant physiological information such as the concentration of chlorophyll and photosynthesis secondary metabolites in this work.
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28

Fernandes, Joelson, William Ferreira Falco, Samuel Leite Oliveira, and Anderson Rodrigues Lima Caires. "Changes in chlorophyll a fluorescence of glyphosate-tolerant soybean plants induced by glyphosate: in vivo analysis by laser-induced fluorescence spectroscopy." Applied Optics 52, no. 13 (April 24, 2013): 3004. http://dx.doi.org/10.1364/ao.52.003004.

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29

Subhash, Narayanan, Changatharayil N. Mohanan, Rupananda J. Mallia, and Vadekkeveetil Muralidharan. "Quantification of stress adaptation by laser-induced fluorescence spectroscopy of plants exposed to engine exhaust emission and drought." Functional Plant Biology 31, no. 7 (2004): 709. http://dx.doi.org/10.1071/fp03253.

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The effects of drought and petrol engine exhaust pollutants, such as SO2 and NO2 and suspended particulate matter (SPM), on the photosynthetic activity of colocasia [Colocasia esculenta (L.) Schott], kacholam (Kaempferia galanga L.) and tapioca (Manihot esculenta Crantz) plants were studied from in vivo laser-induced chlorophyll fluorescence (LICF) spectra. An open-top chamber (OTC) of 2.5 m diameter and 3 m height incorporating an air-filtering unit was developed for this study. Plants grown inside the OTC were exposed to exhaust emissions from a two-stroke Birla Yamaha genset for 10 d, while a control group was maintained outside. Gaseous pollutants and SPM present inside the OTC during the exposure period were measured with a high-volume air sampler. The steady-state LICF spectra of the control and treated plants were recorded in the 650–750-nm region. Fluorescence induction kinetics (Kautsky effect) was also recorded during the stress period from dark-adapted intact plant leaves at the chlorophyll bands of 685 and 730 nm. The vitality indexes (Rfd-685 and Rfd-730) and stress adaptation index (Ap) derived from the induction kinetics were utilised along with the chlorophyll fluorescence intensity ratio (F685 / F730) for evaluation of stress-induced changes in plants. It has been observed that F685 / F730 ratio increased for all plants inside the OTC whereas the Rfd-685, Rfd-730 and Ap values showed a downward trend with increasing pollution stress. As compared to colocasia and tapioca, kacholam plants showed higher resistance to exhaust emission and water stress as well as better capacity to regain its photosynthetic functioning on removal of the stress. Results of this study demonstrate the capability of stress adaptation index for early quantification of the functional impairment of photosynthetic apparatus in different species of plants due to air pollution and drought stresses.
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Yang, Jian, Lin Du, Shuo Shi, Wei Gong, Jia Sun, and Biwu Chen. "Potential of Fluorescence Index Derived from the Slope Characteristics of Laser-Induced Chlorophyll Fluorescence Spectrum for Rice Leaf Nitrogen Concentration Estimation." Applied Sciences 9, no. 5 (March 4, 2019): 916. http://dx.doi.org/10.3390/app9050916.

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Leaf nitrogen concentration (LNC) is a major biochemical parameter for estimating photosynthetic efficiency and crop yields. Laser-induced fluorescence, which is a promising potential technology, has been widely used to estimate the growth status of crops with the help of multivariate analysis. In this study, a fluorescence index was proposed based on the slope characteristics of fluorescence spectrum and was used to estimate LNC. Then, the performance of different fluorescence characteristics (proposed fluorescence index, fluorescence ratios, and fluorescence characteristics calculated by principal component analysis (PCA)) for LNC estimation was analyzed based on back-propagation neural network (BPNN) model. The proposed fluorescence index exhibited more stability and reliability for LNC estimation than fluorescence ratios and characteristics calculated by PCA. In addition, the effect of different kernel functions and hidden layer sizes of BPNN model on the accuracy of LNC estimation was discussed for different fluorescence characteristics. The optimal train functions “trainrp,” “trainbr,” and “trainlm” were then selected with higher R2 and lower standard deviation (SD) values than those of other train functions. In addition, experimental results demonstrated that the hidden layer size has a smaller impact on the accuracy of LNC estimation than the kernel function of the BPNN model.
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31

Takahashi, Kunio, Ken-ichi Mineuchi, Yasufumi Emori, Satoshi Kobayashi, and Hiromitsu Ishii. "Study of Transverse Distribution of Illuminated Laser Light and Laser-Induced Chlorophyll Fluorescence in Plant Leaves by Micro-Fluorescence Imaging (MFI) System." JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN 80, no. 11 (1996): 827–35. http://dx.doi.org/10.2150/jieij1980.80.11_827.

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32

Hoge, Frank E., C. Wayne Wright, Robert N. Swift, and James K. Yungel. "Airborne laser-induced oceanic chlorophyll fluorescence: solar-induced quenching corrections by use of concurrent downwelling irradiance measurements." Applied Optics 37, no. 15 (May 20, 1998): 3222. http://dx.doi.org/10.1364/ao.37.003222.

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33

Pandey, Jitendra Kumar, and R. Gopal. "Laser-Induced Chlorophyll Fluorescence: A Technique for Detection of Dimethoate Effect on Chlorophyll Content and Photosynthetic Activity of Wheat Plant." Journal of Fluorescence 21, no. 2 (December 3, 2010): 785–91. http://dx.doi.org/10.1007/s10895-010-0771-5.

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34

Cowles, Timothy J., James N. Moum, Russell A. Desiderio, and Stanley M. Angel. "In situ monitoring of ocean chlorophyll via laser-induced fluorescence backscattering through an optical fiber." Applied Optics 28, no. 3 (February 1, 1989): 595. http://dx.doi.org/10.1364/ao.28.000595.

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35

Zhu, Dazhou, Qiong Wu, Zhihong Ma, Dongyan Zhang, Wenjiang Huang, and Cheng Wang. "The Determination of Chlorophyll Content in Wheat Leaves by Chemometrics and Laser Induced Fluorescence Spectroscopy." Advanced Science Letters 6, no. 1 (March 15, 2012): 672–75. http://dx.doi.org/10.1166/asl.2012.2312.

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36

Saito, Yasunori, Koh-jiro Kurihara, Hiroaki Takahashi, Fumitoshi Kobayashi, Takuya Kawahara, Akio Nomura, and Satomi Takeda. "Remote Estimation of the Chlorophyll Concentration of Living Trees Using Laser-induced Fluorescence Imaging Lidar." Optical Review 9, no. 2 (March 2002): 37–39. http://dx.doi.org/10.1007/s10043-002-0037-9.

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37

Liu, Weiwei, Jon Atherton, Matti Mõttus, Jean-Philippe Gastellu-Etchegorry, Zbyněk Malenovský, Pasi Raumonen, Markku Åkerblom, Raisa Mäkipää, and Albert Porcar-Castell. "Simulating solar-induced chlorophyll fluorescence in a boreal forest stand reconstructed from terrestrial laser scanning measurements." Remote Sensing of Environment 232 (October 2019): 111274. http://dx.doi.org/10.1016/j.rse.2019.111274.

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38

Sch�chtl, J., G. Huber, F. X. Maidl, E. Sticksel, J. Schulz, and P. Haschberger. "Laser-Induced Chlorophyll Fluorescence Measurements for Detecting the Nitrogen Status of Wheat (Triticum aestivum L.) Canopies." Precision Agriculture 6, no. 2 (April 2005): 143–56. http://dx.doi.org/10.1007/s11119-004-1031-y.

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39

Huzortey, Andrew A., Andreas A. Kudom, Ben A. Mensah, Baah Sefa-Ntiri, Benjamin Anderson, and Angela Akyea. "Water quality assessment in mosquito breeding habitats based on dissolved organic matter and chlorophyll measurements by laser-induced fluorescence spectroscopy." PLOS ONE 17, no. 7 (July 27, 2022): e0252248. http://dx.doi.org/10.1371/journal.pone.0252248.

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Rapid urbanization and its associated pollution can affect water quality in mosquito breeding habitats and, as a result, the ecology and control of mosquito vectors. To understand the effects of pollution on mosquito vectors, an accurate assessment of water quality in breeding habitats is needed. Presently, water quality assessment of mosquito breeding habitats is usually based on the measurement of individual physicochemical parameters. However, several parameters are sometimes difficult to interpret or may not give a clear picture of the overall water quality of the breeding habitats, especially when the pollutants are in complex mixtures. This study employed the use of Laser-Induced Fluorescence (LIF) spectroscopy to assess water quality in breeding habitats of Anopheles, Aedes, and Culex mosquitoes in urban areas in Cape Coast, Ghana. The LIF spectra, using a 445-nm diode laser, were measured from field-collected water samples in the laboratory. The LIF spectra showed the presence of dissolved organic matter (DOM) and chlorophyll in the breeding habitats. The DOM and chlorophyll fluorescence signals were normalised by the Raman vibrational signals to determine water quality in each habitat. The overall water quality was better in Aedes breeding habitats than in Anopheles and Culex breeding habitats. The poor water quality in Anopheles and Culex breeding habitats was due to the presence of high fulvic acid and chlorophyll content, which often reflect pollutants from anthropogenic sources. Anopheles and Aedes habitats were made up of mainly An. coluzzii and Ae. aegypti respectively while Culex species were identified to genus level. The results add up to the growing concern about the breeding of Anopheles in polluted habitats. The study demonstrated for the first time the ability of LIF spectroscopy to assess water quality in mosquito breeding habitats.
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Truax, Kelly, Henrietta Dulai, Anupam Misra, Wendy Kuhne, Peter Fuleky, Celia Smith, and Milton Garces. "Laser-Induced Fluorescence for Monitoring Environmental Contamination and Stress in the Moss Thuidium plicatile." Plants 12, no. 17 (August 30, 2023): 3124. http://dx.doi.org/10.3390/plants12173124.

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The ability to detect, measure, and locate the source of contaminants, especially heavy metals and radionuclides, is of ongoing interest. A common tool for contaminant identification and bioremediation is vegetation that can accumulate and indicate recent and historic pollution. However, large-scale sampling can be costly and labor-intensive. Hence, non-invasive in-situ techniques such as laser-induced fluorescence (LIF) are becoming useful and effective ways to observe the health of plants through the excitation of organic molecules, e.g., chlorophyll. The technique presented utilizes images collected of LIF in moss to identify different metals and environmental stressors. Analysis through image processing of LIF response was key to identifying Cu, Zn, Pb, and a mixture of the metals at nmol/cm2 levels. Specifically, the RGB values from each image were used to create density histograms of each color channel’s relative pixel abundance at each decimal code value. These histograms were then used to compare color shifts linked to the successful identification of contaminated moss samples. Photoperiod and extraneous environmental stressors had minimal impact on the histogram color shift compared to metals and presented with a response that differentiated them from metal contamination.
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41

Desiderio, Russell A., Timothy J. Cowles, James N. Moum, and Michael Myrick. "Microstructure Profiles of Laser-induced Chlorophyll Fluorescence Spectra: Evaluation of Backscatter and Forward-Scatter Fiber-Optic Sensors." Journal of Atmospheric and Oceanic Technology 10, no. 2 (April 1993): 209–24. http://dx.doi.org/10.1175/1520-0426(1993)010<0209:mpolic>2.0.co;2.

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42

Senesi, Giorgio Saverio, Olga De Pascale, Bruno Spolon Marangoni, Anderson Rodrigues Lima Caires, Gustavo Nicolodelli, Vitantonio Pantaleo, and Paola Leonetti. "Chlorophyll Fluorescence Imaging (CFI) and Laser-Induced Breakdown Spectroscopy (LIBS) Applied to Investigate Tomato Plants Infected by the Root Knot Nematode (RKN) Meloidogyne incognita and Tobacco Plants Infected by Cymbidium Ringspot Virus." Photonics 9, no. 9 (September 1, 2022): 627. http://dx.doi.org/10.3390/photonics9090627.

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Recently, studies on climate change have highlighted the central role of photosynthetic mechanisms in the defense response of plants to abiotic and biotic stresses. Photo-sensing and photo-activation are innovative technologies applied for the early detection of plant pathogens in order to prevent the dramatic impact they may have on plants. Chlorophyll Fluorescence Imaging (CFI) and Laser-Induced Breakdown Spectroscopy (LIBS) analytical techniques can be used to evaluate the amount of chlorophyll in plants, which can be altered in the case of biotic and abiotic stresses. In this work, both techniques were applied to two pathogenic model systems, i.e., roots of susceptible tomato plants infected by Meloidogyne incognita and Nicotiana benthamiana plants infected by cymbidium ringspot virus. Experimental evidence is provided and discussed showing that specific application protocols of both methods can be used successfully for the early detection of symptoms of the pathogen attacks of Meloidogyne incognita on tomato roots and of cymbidium ringspot virus infected plants. In particular, a decrease in chlorophyll content was measured by fluorescence imaging, and an increase in Mg++ content was determined by LIBS in both the leaves and stems of infected tomato plants and the leaves of infected plants, with respect to control (non-infected) plants. Thus, the two techniques used have been shown to be able to discriminate satisfactorily between control and infected plants and to provide some insight on the underlying mechanisms of plant defenses again nematodes and viruses.
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Anderson, Benjamin, Moses J. Eghan, Elvis Asare-Bediako, and Paul K. Buah-Bassuah. "Violet diode laser-induced chlorophyll fluorescence: a tool for assessing mosaic disease severity in cassava (Manihot esculentaCrantz) cultivars." Environmental Technology 33, no. 3 (August 18, 2011): 367–72. http://dx.doi.org/10.1080/09593330.2011.575184.

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44

Wang, Yanjuan, Junsheng Wang, Chen Zhou, Gege Ding, Mengmeng Chen, Jiang Zou, Ge Wang, Yuejun Kang, and Xinxiang Pan. "A Microfluidic Prototype System towards Microalgae Cell Separation, Treatment and Viability Characterization." Sensors 19, no. 22 (November 13, 2019): 4940. http://dx.doi.org/10.3390/s19224940.

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There are a huge number, and abundant types, of microalgae in the ocean; and most of them have various values in many fields, such as food, medicine, energy, feed, etc. Therefore, how to identify and separation of microalgae cells quickly and effectively is a prerequisite for the microalgae research and utilization. Herein, we propose a microfluidic system that comprised microalgae cell separation, treatment and viability characterization. Specifically, the microfluidic separation function is based on the principle of deterministic lateral displacement (DLD), which can separate various microalgae species rapidly by their different sizes. Moreover, a concentration gradient generator is designed in this system to automatically produce gradient concentrations of chemical reagents to optimize the chemical treatment of samples. Finally, a single photon counter was used to evaluate the viability of treated microalgae based on laser-induced fluorescence from the intracellular chlorophyll of microalgae. To the best of our knowledge, this is the first laboratory prototype system combining DLD separation, concentration gradient generator and chlorophyll fluorescence detection technology for fast analysis and treatment of microalgae using marine samples. This study may inspire other novel applications of micro-analytical devices for utilization of microalgae resources, marine ecological environment protection and ship ballast water management.
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45

Pieruschka, Roland, Denis Klimov, Zbigniew S. Kolber, and Joseph A. Berry. "Monitoring of cold and light stress impact on photosynthesis by using the laser induced fluorescence transient (LIFT) approach." Functional Plant Biology 37, no. 5 (2010): 395. http://dx.doi.org/10.1071/fp09266.

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Chlorophyll fluorescence measurements have been widely applied to quantify the photosynthetic efficiency of plants non-destructively. The most commonly used pulse amplitude modulated (PAM) technique provides a saturating light pulse, which is not practical at the canopy scale. We report here on a recently developed technique, laser induced fluorescence transient (LIFT), which is capable of remotely measuring the photosynthetic efficiency of selected leaves at a distance of up to 50 m. The LIFT approach correlated well with gas exchange measurements under laboratory conditions and was tested in a field experiment monitoring the combined effect of low temperatures and high light intensity on a variety of plants during the early winter in California. We observed a reduction in maximum and effective quantum yield in electron transport for Capsicum annuum L., Lycopersicon esculentum L. and Persea americana Mill. as the temperatures fell, while a grass community was not affected by combined low temperature and high light stress. The ability to make continuous, automatic and remote measurements of the photosynthetic efficiency of leaves with the LIFT system provides a new approach for studying and monitoring of stress effects on the canopy scale.
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46

TAKAHASHI, Kunio, Ken-ichi MINEUCHI, Yasufumi EMORI, Satoshi KOBAYASHI, and Hiromitsu ISHII. "Study of a Method of Measuring the Transverse Distribution of Illuminating Laser Light and Laser-Induced Chlorophyll Fluorescence in Plant Leaves Using A Micro-Fluorescence Imaging (MFI) System." Journal of Light & Visual Environment 22, no. 1 (1998): 53–62. http://dx.doi.org/10.2150/jlve.22.1_53.

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47

Anderson, Benjamin, Paul K. Buah-Bassuah, and Jonathan P. Tetteh. "Using violet laser-induced chlorophyll fluorescence emission spectra for crop yield assessment of cowpea (Vigna unguiculata (L) Walp) varieties." Measurement Science and Technology 15, no. 7 (May 29, 2004): 1255–65. http://dx.doi.org/10.1088/0957-0233/15/7/005.

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48

Csintalan, Zsolt, Zoltán Tuba, and Hartmut K. Lichtenthaler. "Changes in laser-induced chlorophyll fluorescence ratio F690/F735 in the poikilochlorophyllous desiccation tolerant plant Xerophyta scabrida during desiccation." Journal of Plant Physiology 152, no. 4-5 (January 1998): 540–44. http://dx.doi.org/10.1016/s0176-1617(98)80275-7.

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49

Ruth, B. "Characterization of the photosynthetic system by measuring the laser-induced chlorophyll fluorescence in the msec range from medium distances." Remote Sensing of Environment 56, no. 2 (May 1996): 79–86. http://dx.doi.org/10.1016/0034-4257(95)00134-4.

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50

Pandey, Jitendra Kumar, Gunjan Dubey, and R. Gopal. "Study the effect of insecticide dimethoate on photosynthetic pigments and photosynthetic activity of pigeon pea: Laser-induced chlorophyll fluorescence spectroscopy." Journal of Photochemistry and Photobiology B: Biology 151 (October 2015): 297–305. http://dx.doi.org/10.1016/j.jphotobiol.2014.08.014.

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