Academic literature on the topic 'Fruit elongation'
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Journal articles on the topic "Fruit elongation"
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Williamson, Jeffrey G., and Donald C. Coston. "The Relationship Among Root Growth, Shoot Growth, and Fruit Growth of Peach." Journal of the American Society for Horticultural Science 114, no. 2 (March 1989): 180–83. http://dx.doi.org/10.21273/jashs.114.2.180.
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Abstract The number, length, and elongation rate of white roots were related to vegetative and reproductive growth of young own-rooted ‘Redhaven’ peach trees from June 1985 until Oct. 1986. Root growth of fruiting and nonfruiting trees were similar, except for a period of 3 to 4 weeks each year either during the final stage of fruit growth or immediately after harvest. During these periods, cropping reduced white root length per tree in both years, and total root growth per tree and number of growing root tips in 1986. Number of elongating root tips was correlated with total root elongation and was a better indicator of total root elongation than was mean root elongation rate of individual root tips.
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Braun, Joseph W., and Jeannie K. L. Garth. "Strawberry Vegetative and Fruit Growth Response to Paclobutrazol." Journal of the American Society for Horticultural Science 111, no. 3 (May 1986): 364–67. http://dx.doi.org/10.21273/jashs.111.3.364.
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Abstract Petiole and scape elongation, leaf expansion, and runner formation were reduced by soil application of paclobutrazol (PP333). Runner number was reduced 90–100% by paclobutrazol dosages of 0.2–0.4 mg a.i. per 15-cm pot, accompanied by smaller reductions in leaf expansion (14–29%), petiole elongation (31–59%), and scape elongation (24–47%). Subsequent foliar applied gibberellic acid (GA3) at 50 ppm alleviated the effects of paclobutrazol. Lateral crown formation was promoted in several experiments. Fruit weight was not affected at 0.6 mg a.i. paclobutrazol per pot, but scape elongation was reduced by 51%. Chemical names used: β-[(4-chlorophenyl)methyl]α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
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Jolliffe, P. A., and W. C. Lin. "Predictors of Shelf Life in Long English Cucumber." Journal of the American Society for Horticultural Science 122, no. 5 (September 1997): 686–90. http://dx.doi.org/10.21273/jashs.122.5.686.
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Variation in shelf life of greenhouse-grown `Mustang' cucumber (Cucumis sativus L.) fruit was enhanced by preharvest experimental treatments of fruit thinning and fruit shading. Treatments also affected the dynamics of fruit elongation, fruit color at harvest, and chlorophyll fluorescence of the pericarp. Fruit color (grey level) at harvest, as measured by image analysis, had the highest simple (positive) correlation with shelf life. Rapid elongation and high photochemical quenching of fluorescence also characterized fruit having longer shelf life. The ability to predict cucumber yellowing is improved using a multiple regression approach, but prediction achieved by the best subset model is still too low to segregate commercially fruit having a short shelf life.
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Mishyna, Maryia, Nikolai Laman, Valery Prokhorov, John Solomon Maninang, and Yoshiharu Fujii. "Identification of Octanal as Plant Growth Inhibitory Volatile Compound Released from Heracleum sosnowskyi Fruit." Natural Product Communications 10, no. 5 (May 2015): 1934578X1501000. http://dx.doi.org/10.1177/1934578x1501000518.
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Heracleum sosnowskyi Manden of the Apiaceae family is a malignant invasive plant in Eastern Europe, Belarus and Russia. The species is known for its prolific seed production, which has been linked to the plant's invasive success. The fruit also has a strong aroma, but the contribution of the fruit's volatile constituent to out-compete neighboring plants has not been fully established. In this study, fruit volatiles of H. sosnowskyi and conspecifics (i.e. H. asperum, H. lescovii, H. dissectum, H. hirtum) were identified by headspace gas chromatography-mass spectrometry (HS-GC-MS). Octyl acetate, octanol, octanal, hexyl isobutyrate, and hexyl-2-methyl butyrate were found to be the principal volatiles. Using authentic standards, the growth-inhibitory property of the individual compounds was assayed by the novel Cotton swab method. Assay results with lettuce ( Lactuca sativa) showed that octanal strongly inhibited seed germination and radicle elongation of seedlings. The results suggest that octanal may be the main contributor to the allelopathic activity of H. sosnowksyi fruits. Furthermore, the mixture of fruit volatiles from the invasive H. sosnowskyi more strongly delayed lettuce seedling elongation than the volatiles from fruits of the non-invasive H. asperum, H. lescovii, H. dissectum and H. hirtum. Thus, the present study is the first to demonstrate the possible involvement of fruit volatiles of Heracleum species in plant-plant interaction.
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Haouari, Afef, Marie-Christine Van Labeke, Kathy Steppe, Fethi Ben Mariem, Mohamed Braham, and Mohamed Chaieb. "Fruit thinning affects photosynthetic activity, carbohydrate levels, and shoot and fruit development of olive trees grown under semiarid conditions." Functional Plant Biology 40, no. 11 (2013): 1179. http://dx.doi.org/10.1071/fp13094.
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Olive (Olea europaea L.) production is marked by annual oscillations as trees alternate from high to low crop loads in successive years. Gas exchanges and carbohydrate content of leaves and fruits in olive tree (O. europaea cv. Besbassi) were monitored at pit hardening and fruit ripening. After fruit set, three crop loads were applied (100%, 50% and 25% of the initial fruit load) by manual thinning. Severe fruit thinning reduced photosynthesis, stomatal conductance and intercellular CO2 concentration. Crop load had no significant effect on chlorophyll fluorescence parameters. The reduction of 75% of the initial crop load favoured the accumulation of starch in leaves and soluble sugars in leaves and fruits. The reduction in initial fruit load had a significant positive effect on the current year’s shoot elongation and on inflorescence number the following spring. To increase the fruit size, a strong thinning (75%) was necessary, which coincided with the highest shoot vigour. Moderate thinning (50%) hardly affected leaf carbohydrate content and fruit size, but photosynthetic capacity was only limited at fruit ripening.
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Wang, Yanping, Josh P. Clevenger, Eudald Illa-Berenguer, Tea Meulia, Esther van der Knaap, and Liang Sun. "A Comparison of sun, ovate, fs8.1 and Auxin Application on Tomato Fruit Shape and Gene Expression." Plant and Cell Physiology 60, no. 5 (February 8, 2019): 1067–81. http://dx.doi.org/10.1093/pcp/pcz024.
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Abstract Elongated tomato fruit shape is the result of the action of the fruit shape genes possibly in coordination with the phytohormone auxin. To investigate the possible link between auxin and the fruit shape genes, a series of auxin (2,4-D) treatments were performed on the wild-type and the fruit shape near-isogenic lines (NILs) in Solanum pimpinellifolium accession LA1589 background. Morphological and histological analyses indicated that auxin application approximately 3 weeks before anthesis led to elongated pear-shaped ovaries and fruits, which was mainly attributed to the increase of ovary/fruit proximal end caused by the increase of both cell number and cell size. Fruit shape changes caused by SUN, OVATE and fs8.1 were primarily due to the alterations of cell number along different growth axes. Particularly, SUN caused elongation by extending cell number along the entire proximal-distal axis, whereas OVATE caused fruit elongation in the proximal area, which was most similar to the effect of auxin on ovary shape. Expression analysis of flower buds at different stages in fruit shape NILs indicated that SUN had a stronger impact on the transcriptome than OVATE and fs8.1. The sun NIL differentially expressed genes were enriched in several biological processes, such as lipid metabolism, ion transmembrane and actin cytoskeleton organization. Additionally, SUN also shifted the expression of the auxin-related genes, including those involved in auxin biosynthesis, homeostasis, signal transduction and polar transport, indicating that SUN may regulate ovary/fruit shape through modifying the expression of auxin-related genes very early during the formation of the ovary in the developing flower.
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Pan, Yupeng, Birong Chen, Lijun Qiao, Feifan Chen, Jianyu Zhao, Zhihui Cheng, and Yiqun Weng. "Phenotypic Characterization and Fine Mapping of a Major-Effect Fruit Shape QTL FS5.2 in Cucumber, Cucumis sativus L., with Near-Isogenic Line-Derived Segregating Populations." International Journal of Molecular Sciences 23, no. 21 (November 2, 2022): 13384. http://dx.doi.org/10.3390/ijms232113384.
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Cucumber (Cucumis sativus L.) fruit size/shape (FS) is an important yield and quality trait that is quantitatively inherited. Many quantitative trait loci (QTLs) for fruit size/shape have been identified, but very few have been fine-mapped or cloned. In this study, through marker-assisted foreground and background selections, we developed near-isogenic lines (NILs) for a major-effect fruit size/shape QTL FS5.2 in cucumber. Morphological and microscopic characterization of NILs suggests that the allele of fs5.2 from the semi-wild Xishuangbanna (XIS) cucumber (C. s. var. xishuangbannesis) reduces fruit elongation but promotes radial growth resulting in shorter but wider fruit, which seems to be due to reduced cell length, but increased cellular layers. Consistent with this, the NIL carrying the homozygous XIS allele (fs5.2) had lower auxin/IAA contents in both the ovary and the developing fruit. Fine genetic mapping with NIL-derived segregating populations placed FS5.2 into a 95.5 kb region with 15 predicted genes, and a homolog of the Arabidopsis CRABS CLAW (CsCRC) appeared to be the most possible candidate for FS5.2. Transcriptome profiling of NIL fruits at anthesis identified differentially expressed genes enriched in the auxin biosynthesis and signaling pathways, as well as genes involved in cell cycle, division, and cell wall processes. We conclude that the major-effect QTL FS5.2 controls cucumber fruit size/shape through regulating auxin-mediated cell division and expansion for the lateral and longitudinal fruit growth, respectively. The gibberellic acid (GA) signaling pathway also plays a role in FS5.2-mediated fruit elongation.
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Mumtaz, Muhammad Ali, Fangman Li, Xingyu Zhang, Jinbao Tao, Pingfei Ge, Ying Wang, Yaru Wang, Wenxian Gai, Haiqiang Dong, and Yuyang Zhang. "Altered brassinolide sensitivity1 Regulates Fruit Size in Association with Phytohormones Modulation in Tomato." Horticulturae 8, no. 11 (October 31, 2022): 1008. http://dx.doi.org/10.3390/horticulturae8111008.
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BRs (Brassinosteroids) regulate many essential pathways related to growth, cell elongation, cell expansion, plant architecture, and fruit development. The potential exogenous application of BR-derivatives has been proven to stimulate plant growth and development, including quality attributes of fruits, whereas its biosynthesis inhibition has shown the opposite effect. In this study, BR-insensitive tomato mutants were used to reveal the potential function of BR signaling in the regulation of fruit development to elaborate the regulatory mechanism of BR signaling in tomato fruits. The BR-signaling mutant exhibited a typical dwarf phenotype and reduced vegetative growth, fruit size, and weight. Microscopic and transcriptional evaluation of the abs1 mutant fruits implies that reduced cell size and number are responsible for the phenotypic variations. Additionally, we also found that the altered content of phytohormones, such as auxin, gibberellin, cytokinin, and ethylene levels, contributed to altered fruit development. Moreover, fruit growth and cell development-specific gene expression levels were downregulated in BR-insensitive plants; culminating in reduced cell size, cell number, and cell layers. These findings provide insight into physio-chemical changes during fruit development in response to BR-insensitivity.
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Chao, Ema E., and Hans E. Gruen. "Intracellular activity of mycelial proteinases during fruit-body development in Flammulina velutipes." Canadian Journal of Botany 65, no. 3 (March 1, 1987): 518–25. http://dx.doi.org/10.1139/b87-066.
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In the mycelium of Flammulina velutipes cultured on potato–glucose solution the concentration of water-soluble protein began to decrease steeply before fruit bodies formed, but the total amount of protein per culture decreased only when fruit bodies began to elongate rapidly. The level remained very low during rapid elongation. Proteinase activity per unit weight of mycelium against milk protein and azoalbumin decreased in parallel with the concentration of mycelial protein. Activity against azure blue – hide powder was low until the onset of rapid fruit-body elongation and reached a maximum later during that phase. Azoalbumin was hydrolyzed more actively than hide powder. Proteolytic activity per gram of mycelium against mycelial protein was almost the same before fruiting as during rapid fruit-body elongation. Specific activities per milligram protein against the three types of nonnative substrates increased in parallel to a maximum late during rapid elongation when protein concentration was lowest. Specific activity against native mycelial protein was also higher in extracts from older mycelia. Proteolysis was optimal near neutral pH and very low at pH 3.2. Tests with group-specific proteinase inhibitors showed that metallo-proteinases predominate in the mycelium. Serine, and to a lesser extent carboxyl and thiol proteinases, were also present. Neither endogenous inhibitors nor activators of proteolysis were detected.
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Xin, Tongxu, Zhen Zhang, Shuai Li, Shu Zhang, Qing Li, Zhong-Hua Zhang, Sanwen Huang, and Xueyong Yang. "Genetic Regulation of Ethylene Dosage for Cucumber Fruit Elongation." Plant Cell 31, no. 5 (March 26, 2019): 1063–76. http://dx.doi.org/10.1105/tpc.18.00957.
Full textDissertations / Theses on the topic "Fruit elongation"
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Wu, Shan. "The roles of OVATE and other elongation genes in regulating proximal-distal patterning of tomato fruit." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437586702.
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DI, MARZO MAURIZIO. "THE MADS-DOMAIN SEEDSTICK PLAYS FUNDAMENTAL ROLES DURING TRANSMITTING TRACT DEVELOPMENT AND FRUIT GROWTH IN ARABIDOPSIS THALIANA." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/717626.
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The MADS-box gene SEEDSTICK (STK) controls several aspects of plant reproduction. STK is co-expressed with CESTA (CES), a basic Helix-Loop-Helix (bHLH) transcription factor-encoding gene. CES was reported to control redundantly with the brassinosteroid positive signaling factors BRASSINOSTEROID ENHANCED EXPRESSION1 (BEE1) and BEE3 the transmitting tract development. Through the characterization of the stk ces-2 double mutant, we observed that STK and CES act together in the regulation of transmitting tract development. Combining the stk with ces-2 bee1 bee3 we have obtained the quadruple mutant showed a clear increase of the unfertilized ovules and septum defects. In the quadruple mutant carpel fusion was compromised, causing the formation of holes at the center of the septum where transmitting tract differentiates. These phenotypes do not allow a proper pollen tube growth in the double mutant stk ces-2, and even more in the quadruple mutant bee1 bee3 stk ces-2 leading to high number of unfertilized ovules. The transcriptome profile of the quadruple mutant bee1 bee3 stk ces-2 compared to wild type revealed a small subset of misregulated genes, which probably act downstream of the transcription factor described above, mainly involved in cell death, the extracellular matrix of the transmitting tract, cell wall composition and auxin signaling. This specific subset of downstream target genes controlled directly or indirectly by STK-CES-BEE1-BEE3 protein complex, open doors to a new regulatory network controls transmitting tract development. Altogether our data reveal new insights in the regulation of transmitting tract development together by bHLH and MADS-box transcription factors.Upon fertilization, the ovary increases in size and undergoes a complex developmental process to become a fruit. The fruit of Arabidopsis thaliana is named silique. We show that cytokinins (CK), required to define ovary size before fertilization, have to be degraded to obtain the correct fruit growth. The expression of CYTOKININ OXIDASE DEHYDROGENASE 7 (CKX7), which encodes a cytosolic CK degrading enzyme, is directly regulated post-fertilization by the MADS-box transcription factor STK. Similar to stk, two ckx7 mutant alleles possess shorter fruits compared to wild type. Quantification of CKs revealed that stk has high CK levels during fruit elongation, which negatively control cell expansion during fruit development, compromising fruit growth. Overexpression of CKX7 partially complements the stk fruit phenotype. We show that CKX6 does not regulate fruit elongation process. CKX6 encodes for one of the fourth CK degrading enzymes that acts in the apoplast. The CKX6 promoter is not active during fruit elongation phases. Moreover, the ckx6 mutant does not display differences in fruit length when compared to wild type. Finally, we show that STK is also required for the correct expression of the MADS-box gene FUL, which is considered the master regulator of valve elongation in fruit. The double mutant stk ful displayed shorter siliques when compared to wild type, but also respect to the two single mutants. The additive phenotype of the double mutant stk ful suggests the possibility that the two MADS-box transcription factors act in two parallels pathways that can regulate fruit elongation process. Overall, we provide novel insights into the regulatory pathway that control fruit growth.
Book chapters on the topic "Fruit elongation"
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Kamada, T. "Stipe Elongation in Fruit Bodies." In Growth, Differentiation and Sexuality, 367–79. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-662-11908-2_22.
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Soares, Zilmar Timoteo, Amanda Araújo Nascimento, and Veronica Santos da Silva. "Biotechnology applied to the buriti fruit (Mauritia flexuosa Mart.)." In METHODOLOGY FOCUSED ON THE AREA OF INTERDISCIPLINARITY- V1. Seven Editora, 2023. http://dx.doi.org/10.56238/methofocusinterv1-020.
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Plastic has environmentally unfavorable factors. First, it is about its origin, coming from petroleum, a non-renewable source, hydrophobic materials that do not allow the action of microorganisms in its molecular chain, taking hundreds of years to decompose. In this sense, there is the buriti palm whose fruit is rich in natural polymer, which can be produced a biodegradable plastic, due to its organic characteristic, which decomposes easily and quickly causing without damage to the environment. With that, the. The objective of this research was to develop a flexible, biodegradable bioplastic based on natural polymers from renewable sources from the epicarp, mesocarp, buriti fruit endocarp and cassava starch by cooking process. Initially, a dimensional characterization of the buriti fruit was carried out with 120 individuals. Elaboration of different bioplastics with buriti fruit matrix in 90, 95 and 98% associated with cassava starch in 2, 5 and 10%, plasticized with glycerol. The characterizations of bioplastics were carried out through the evaluation of subjectivity, thickness, mechanical properties, opacity, color, water solubility, temperature resistance test, chemical resistance and biodegradation in water and soil. All bioplastics formed were visually transparent in 80% and opaque in 20%. With the increase in the addition of cassava starch, it caused an increase in thickness, permeability to water vapor and tensile strength, generating a decrease in their opacity. In evaluating the subjectivity of the samples, homogeneity was around 88.53%, flexibility 80% and deformation 8.6%. In the strength tests, the epicarp bioplastic showed low elongation (91.20 Mpa), while the endocarp showed greater elongation (4.41%) and low strength (42.50 Mpa). As for the evaluation of opacity, the endocarp exhibited a larger radius of 1.72cm, while the smallest length was manifested in the bioplastic epicarp 0.63cm. The bioplastics were subjected to temperatures of 60, 80, 100, 110 and 120°C, and in the first temperatures they remained at normal levels, from 100°C onwards, curvatures, dryness and cracks appeared. Based on these results, the concentrations of the mixture components were changed to allow the obtainment of decorative bioplastics, with adequate properties by the cooking process. Thus, it can be said that the production of composite bioplastics based on the epicarp, mesocarp and endocarp of the buriti fruit and added with cassava starch, plasticized with glycerol, by the cooking process is environmentally and economically viable.
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Asif, Rizwan, Riffat Yasmin, Madiha Mustafa, Ana Ambreen, Modasrah Mazhar, Abdul Rehman, Shehla Umbreen, and Mukhtiar Ahmad. "Phytohormones as Plant Growth Regulators and Safe Protectors against Biotic and Abiotic Stress." In Plant Hormones - Recent Advances, New Perspectives and Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102832.
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Plants are playing important role in the planet by providing food for humans and stability in the environment. Phytohormones are key regulators in various physiological processes and among the most important small signaling molecules affecting plant growth and yield production. These biochemical also initiate adaptive responses caused by external stimuli, such as biotic and abiotic stress. Generally, on the basis of physiology, plant hormones roughly fall into two classes. In class one, phytohormones fall which is responsible for plants growth-promoting activities, such as cell division, cell elongation, seed and fruit development, and pattern of differentiation. On the other hand, the second class of hormone play important role in plants’ response, such as biotic and abiotic stresses. Some other hormones, such as jasmonates, salicylic acid, brassinosteroids, and strigolactones, also play a key role in plants. Their biochemical signaling network and their crosstalk ability make plant hormones excellent candidates to optimize plant growth and/or mediate abiotic and biotic stresses in agriculture. In the end, the future trends of plant hormone analysis are exploring plant hormones and their applications. We believe the perspective may serve as guidance for the research of plant hormones in the analytical, environmental, and botanical fields.
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Guadalupe García, María, and Martin A. Masuelli. "Effect of Cross-Linking Agent on Mechanical and Permeation Properties of Criolla Orange Pectin." In Pectins [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102976.
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Pectin from orange peel was extracted and cross-linked, applying different cross-linking agents to visualize any effect on its mechanical and permeation properties. Calcium chloride (II) and iron chloride (III) were the cross-linking agents. Besides, commercial pectin was also used to compare its properties with neat orange pectin. Tensile testing showed mechanical stiffness of the orange pectin matrix in the presence of cross-linking agents. Calcium ions better cross-linked the polymer matrix as shown by their highest tensile strength and elastic modulus, with moderate elongation at break. Iron ions showed a weaker cross-linking effect on the pectin matrix, improving the elastic modulus but retaining almost the same tension strength. Lower elongation at break concerning neat orange pectin was observed for cross-linked samples. Water uptake (WU) and water vapor permeation (WVP) of cross-linked samples had lower values than those of neat orange pectin. However, these results are still high compared with synthetic polymers. Finally, gas permeation assays were performed using N2, O2 and CO2 gases, according to exchangeable gases in fresh fruits and vegetable packaging. Results showed a conveniently modified atmosphere effect by avoiding CO2 permeation and stabilizing N2 and O2 selectivity.
Conference papers on the topic "Fruit elongation"
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Wang, Xueliang, Zhiguo Qu, and Yaping Wang. "Fabrication and Mechanical Property of Bioinspired Three Dimensional Amorphous Carbon Membrane As Anode in Lithium Ion Battery." In ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/mnhmt2019-3990.
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Abstract 3D amorphous carbon-based membrane materials with continuous carbon skeleton were obtained from the fruit waste pomelo peel. The microstructure shows honeycomb in the transverse direction with pore size ranging from 50∼100 μm, while in the longitudinal direction, the inner surface of the carbon membrane shows unique structure, i.e., rollable ladders with carbon rungs twinkled intimately around the vertical stringers, which is considered to contribute to the mechanical strength of the carbon membrane. The tensile test indicates that prolonged yield stage is observed in the stress-strain curve of the membrane material, the corresponding fracture morphology showing different fracture surfaces, which confirms the alleviation of the applied load by changing the crack direction. In addition, the elastic modulus of the carbon membrane material is 140 MPa. The elongation of the yield period is considered to facilitate the structure stability of the carbon membrane material as anode material in Lithium-ion battery (LIBs).
Reports on the topic "Fruit elongation"
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Shoseyov, Oded, Steven A. Weinbaum, Raphael Goren, and Abhaya M. Dandekar. Biological Thinning of Fruit Set by RNAase in Deciduous Fruit Trees. United States Department of Agriculture, August 1993. http://dx.doi.org/10.32747/1993.7568110.bard.
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Fruit thinning is a common and necessary practice for commercial fruit production in many deciduous tree fruit species. Fruit thinning in apple may be accomplished with a variety of chemical thinning agents, but the use of these chemicals is a subject of environmental concern. It has been shown recently that RNase enzyme, secreted from the stigma and the style, inhibits pollen germination and pollen tube elongation. In this study we have been able to show that Aspergillus niger B-1 RNase can effectively inhibit peach and apple pollen germination, and tube elongation in-vitro, as well as thin fruit in peach and apple, and reduce the number of seeds in citrus. The objectives of the research were to detrmine the conditions for effective thinning of (USA and Israel), develop fermentation process for cost effective production of RNase from A. niger. (Israel), and clone apple S-RNase cDNA (USA). All the objectives of the research were addressed. We have determined the optimal fermentation conditions for cost effective production of the A. niger at a 20,000 liters scale. TheA. niger B1 RNase was isolated to homogeneity and its kinetic and biochemical properties including its N-terminal sequence were fully characterized. The field test results both in Israel and California have shown variability in effectiveness and more work is needed to define the RNase concentration necessary to completely inhibit pollen development. Plant transformation vectors expressing anti-sense apple S-RNase genes were constructed (USA) with an attempt to produce self compatible transgenic apple trees. Bovine S-Protein cDNA was cloned and successfully expressed in E. coli (Israel). Plant transformation vector expressing the S-Protein gene was constructed (USA) with an attempt to produce transgenic plants expressing S-protein in the style. Exogenous application of S-peptide to these plants will result in active RNase and consequently prevention of fertilization.
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Chalutz, Edo, Michael Wisniewski, Samir Droby, Yael Eilam, and Ilan Chet. Mode of Action of Yeast Biocontrol Agents of Postharvest Diseases of Fruits. United States Department of Agriculture, June 1996. http://dx.doi.org/10.32747/1996.7613025.bard.
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In a previous BARD-supported study, three of the investigators of this research were involved in a study on biological control of postharvest diseases of citrus and deciduous fruits. Several naturally occurring, non-antibiotic producing yeast antagonists were identified. Application of some of these antagonists resulted in very high levels of biocontrol under laboratory conditions but lower efficacy in semi-commercial tests. It was felt that the lack of knowledge on the mode of action of the biocontrol agents was limiting their efficient use. The current study was aimed at narrowing this gap in our knowledge. Two specific objectives were outlined: to study the mechanism by which calcium salts enhance biocontrol activity and to determine the role, if any, of the yeast extracellular materials and/or enzymes which degrade fungal cell walls during the interaction between the antagonists, the pathogen and the host. CaCl2 but not MgCl2, inhibited spore germination, and germ-tube elongation of Botrytis cinerea, Penicillium expansum and P. digitatum in culture. It also inhibited the pectinolytic activity of the pathogens. Biocontrol of apple decay by isolate 182 of Candida oleophila, an effective biocontrol agent, was enhanced by the addition of CaCl2 whereas there was no effect on the biocontrol activity of isolate 247 of this yeast. Similarly, CaCl2 enhanced efficacy of the US-7 isolate of Pichia guilliermondii in reducing infection of P. digitatum in citrus fruit. CaCl2 by itself also reduced the infection of peel wounds and stimulated ethylene production by grapefruit peel. This antagonist exhibited a very high ability to maintain cytosolic Ca2+ homeostasis when exposed to high CaCl2 concentrations. It is postulated, therefore, that enhanced biocontrol activity by calcium is the result of direct inhibition of the pathogen by calcium ions on spore germination and metabolism and indirectly due to the ability of the biocontrol agent to maintain normal metabolism in the presence of high levels of calcium. The extracellular materials produced by P. guilliermondii in culture and on the fruit inhibited, at low concentrations, the pathogen in culture and reduced percent infection of the fruit. The direct inhibition of the pathogen by these materials may thus be involved in the mode of action of the antagonist. This study contributed to our knowledge on the action of calcium salts and the yeast antagonist extracellular materials on biocontrol activity and will contribute to a more efficient use of this technology in the control of postharvest diseases of fruits.