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Plant physiology

About: Plant physiology is a research topic. Over the lifetime, 1537 publications have been published within this topic receiving 72038 citations.


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Journal ArticleDOI
18 Nov 2019-PLOS ONE
TL;DR: It is concluded that overexpression of SiDHN gene can promote cold and drought tolerance of transgenic tomato plants by inhibiting cell membrane damage, protecting chloroplasts, and enhancing the reactive oxygen species scavenging capacity.
Abstract: Dehydrins are late embryogenesis abundant proteins that help regulate abiotic stress responses in plants. Overexpression of the Saussurea involucrata dehydrin gene SiDHN has previously been shown to improve water-use efficiency and enhance cold and drought tolerance of transgenic tobacco. To understand the mechanism by which SiDHN exerts its protective function, we transformed the SiDHN gene into tomato plants (Solanum lycopersicum L.) and assessed their response to abiotic stress. We observed that in response to stresses, the SiDHN transgenic tomato plants had increased contents of chlorophyll a and b, carotenoid and relative water content compared with wild-type plants. They also had higher maximal photochemical efficiency of photosystem II and accumulated more proline and soluble sugar. Compared to those wild-type plants, malondialdehyde content and relative electron leakage in transgenic plants were not significantly increased, and H2O2 and O2- contents in transgenic tomato plants were significantly decreased. We further observed that the production of stress-related antioxidant enzymes, including superoxide dismutase, ascorbate peroxidase, peroxidase, and catalase, as well as pyrroline-5-carboxylate synthetase and lipid transfer protein 1, were up-regulated in the transgenic plants under cold and drought stress. Based on these observations, we conclude that overexpression of SiDHN gene can promote cold and drought tolerance of transgenic tomato plants by inhibiting cell membrane damage, protecting chloroplasts, and enhancing the reactive oxygen species scavenging capacity. The finding can be beneficial for the application of SiDHN gene in improving crop tolerance to abiotic stress and oxidative damage.

36 citations

Journal ArticleDOI
TL;DR: Ethylene is involved in regulating germination as an initiator of the process rather than consequence, and that ethylene promotes germination by modulating the endogenous concentration of H2O2 in germinating seeds under salinity is suggested.
Abstract: The capacity of plants to achieve successful germination and early seedling establishment under high salinity is crucial for tolerance of plants to salt. The gaseous hormone ethylene has been implicated in modulating salt tolerance, but the detailed role of how ethylene modulates the response of early seedling establishment to salt is unclear. To better understand the role of the ethylene signal transduction pathway during germination and seedling establishment, an ethylene insensitive mutation (ein2-5) and an ethylene sensitive mutation (ctr1-1) of Arabidopsis were analyzed under saline conditions and compared with the wild type plant (Col-0) as control. High salinity (>100 mM NaCl) inhibited and delayed germination. These effects were more severe in the ethylene insensitive mutants (ein2-5) and less severe in the constitutive ethylene sensitive plants (ctr1-1) compared with Col-0 plants. Addition of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) or inhibitors of ethylene action implied that ethylene was essential for early seedling establishment under normal and saline conditions. Salt stress increased the endogenous concentration of hydrogen peroxide (H2O2) in germinating seeds and ACC reduced its concentration. Our results suggest that ethylene promotes germination under salinity by modulating the endogenous concentration of H2O2 in germinating seeds. These findings demonstrate that ethylene is involved in regulating germination as an initiator of the process rather than consequence, and that ethylene promotes germination by modulating the endogenous concentration of H2O2 in germinating seeds under salinity.

36 citations

Journal ArticleDOI
TL;DR: In this paper, a hydroponic experiment in which rice plants were supplied with different N forms (NO3 ``( −, NH4ウス + and mixed-N) was conducted, and the intrinsic mechanisms involved in photosynthesis, root-shoot carbon partitioning, and hormone signalling were investigated.
Abstract: To investigate whether mixed-N (NO3 − + NH4 +) nutrition can enhance rice growth under water-deficit condition, a hydroponic experiment in which rice plants were supplied with different N forms (NO3 −, NH4 + and mixed-N) was conducted, and the intrinsic mechanisms involved in photosynthesis, root-shoot carbon partitioning, and hormone signalling were investigated. Water stress was found to decrease rice biomass, leaf area, chlorophyll and Rubisco contents. However, mixed-N nutrition substantially alleviated these inhibitions compared with NO3 − nutrition alone. Mixed-N nutrition also maintained a higher electron transport rate, actual photochemical efficiency of PSII, and non-photochemical quenching, causing higher photosynthesis and photochemical efficiency. Water stress up-regulated leaf sucrose-phosphate synthase (SPS), but down-regulated acid invertase (InvA). However, leaf InvA and root sucrose synthase in the cleavage direction (SSc) in NO3 − nutrition was higher than that in mixed-N nutrition. Water stress decreased indole acetic acid (IAA) content in leaves and cytokinins content in roots, but their contents in mixed-N nutrition were higher than those in NO3 − nutrition. In mixed-N nutrition, the up-regulation of SPS and IAA in leaves and the reduction of sucrose metabolism (SSc and InvA) in roots jointly resulted in the accumulation of sucrose in leaves and the inhibition of its transportation to roots, finally reducing the root:shoot ratio (R/S). The reduced R/S provides more photosynthates for shoots and increases the utilisation efficiency, thereby strengthening the water-deficit tolerance of plants. We concluded that the strengthened water-deficit tolerance in mixed-N-supplied rice was closely associated with higher accumulation of dry matter mainly via improvement of photosynthesis and photochemical efficiency, hormone balance, and coupling with root-shoot carbon partitioning.

36 citations

Journal ArticleDOI
TL;DR: Glyphosate herbicide caused oxidative stress and exhibited negative effects on photosynthesis and gas exchange of peanut [Arachis hypogaea L. cv. Giza (G) 5 and 6] leaves.
Abstract: Glyphosate herbicide caused oxidative stress and exhibited negative effects on photosynthesis and gas exchange of peanut [Arachis hypogaea L. cv. Giza (G) 5 and 6] leaves. We demonstrated that glyphosate caused various morphological symptoms, such as chlorosis, yellowing, and appearance of curly edges in leaves treated with high doses of herbicide in both cultivars; however, the G5 cultivar was more sensitive and showed severer symptoms. Glyphosate lowered photosynthesis and reduced contents of pigments and proteins as well as free amino acids in both cultivars. The gas-exchange parameters, such as photosynthetic (PN) and transpiration rate (E), were highly altered by the glyphosate application. For example, PN and E were reduced by 65 and 61%, respectively, in G5 treated with high dose of glyphosate compared with control. Antioxidant enzymes, such as peroxidase, catalase, ascorbate peroxidase, and superoxide dismutase were induced by both low and high concentrations in the glyphosate-treated leaves. Moreover, the level of lipid peroxidation, indicated by a malondialdehyde content, as well as the hydrogen peroxide content increased in the glyphosate-treated leaves. However, an increase in total antioxidant activity was detected in leaves and this reflected changes in the antioxidant status and accumulation of antioxidants as a defense mechanism against glyphosate toxicity in peanut.

36 citations

Journal ArticleDOI
TL;DR: The results of photoinhibition and relaxation on exposure of red and green leaves to monochromatic blue light showed that effective quantum yield of PSII recovers faster and completely under darkness in juvenile red leaves as compared to mature green leaves, supporting the role of anthocyanin pigments in protecting both PSII and PSI in the red leaves.

36 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023218
2022445
202179
202069
201967
201869