Photoinactivation of Catalase Occurs under Both High- and Low-Temperature Stress Conditions and Accompanies Photoinhibition of Photosystem II

In this study, we evaluated the effects of low and sub-zero temperature on the fast chlorophyll fluorescence transient (OJIP) and OJIP-derived parameters in 4 different mosses: Sphagnum girgensohnii, Polytrichum formosum, Hylocomium splendens and Pleurozium schreberi. The low temperature stress was applied on the mosses for 90 min. at 3 different temperatures (5°C, -1°C and -10°C). To investigate the effects of this stress on the functioning of photosystem II (PS II), the chlorophyll fluorescence measurements were taken at control temperature (22°C) and, after a 90 min. acclimation period, at each experimental temperature. The shape of OJIP curves and chlorophyll fluorescence parameters were found temperature-dependent in all the species. The mosses differed in their sensitivity to the stress but general trends in response to low temperature were similar. The results support the idea that S. girgensohnii is less resistant to low temperature stress than the other species. We were also interested in the K and L steps in OJIPs, representing different disorders caused by low temperature. The K-step was seen in P. formosum and P. schreberi and the L-step in H. splendens and S. girgensohnii.

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Morphological, Physiological and Biochemical Response to Low Temperature Stress in Tomato (Solanum lycopersicum L.): A Review

International Journal of Bio-resource and Stress Management ◽

10.23910/1.2021.2480 ◽

2021 ◽

Vol 12 (6) ◽

pp. 706-712

Author(s):

D. K. Yadav ◽

◽

Yogendra K. Meena ◽

L. N. Bairwa ◽

Uadal Singh ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Low Temperature ◽

Temperature Stress ◽

Tomato Plant ◽

Reactive Oxygen ◽

Pollen Sterility ◽

Low Temperature Stress ◽

Stress Conditions ◽

Oxygen Species ◽

Physiological And Biochemical

Growth and productivity are traumatized by the low temperature that triggers a series of physiological, morphological, molecular and biochemical changes in plants that eventually disturb plant life. Most of the cultivable lands of the world are adversely affected by temperature stress conditions which have an adverse impact on global tomato productivity. Plants undergo several water related metabolic activities for their survival during cold stress conditions. Understanding the morphological, physiological and biochemical reactions to low temperature is essential for a comprehensive view of the perception of tomato plant tolerant mechanism. This review reports some aspects of low temperature inflated changes in physiological and biochemical in the tomato plant. Low temperature stress influences the reproductive phases of plants with delayed flowering which enhance pollen sterility resultant drastically affects the harvest yield. It also decreases the capacity and efficiency of photosynthesis through changes in gas exchange, pigment content, chloroplast development and decline in chlorophyll fluorescence photosynthetic attributes. Amassing of osmoprotectant is another adaptive mechanism in plants exposed to low temperatures stress, as essential metabolites directly participate in the osmotic adjustment. Furthermore, low temperature stress enhanced the production of reactive oxygen species (ROS) which may oxidize lipids, proteins and nucleic acids which bring in distortion at the level of the cell. At the point when extreme reactive oxygen species produced, plants synthesize antioxidant enzymes and osmoprotectants that quench the abundance of reactive oxygen species. These reviews focus on the capacity and techniques of the tomato plant to react low temperature stress.

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Exogenous Foliar Melatonin Improves Cotton (Gossypium Hirsutum L.) Physio-Biochemical Characteristics Under the Synergetic Effects of Low Temperature and Salinity Stress

10.21203/rs.3.rs-1045095/v1 ◽

2021 ◽

Author(s):

Yuanyuan Fu ◽

Abdoul Kader Mounkaila Hamani ◽

Wenjun Sun ◽

Hongbo Wang ◽

Abubakar Sunusi Amin ◽

...

Keyword(s):

Low Temperature ◽

Temperature Stress ◽

Salinity Stress ◽

Membrane Damage ◽

Ion Homeostasis ◽

Physiological Mechanism ◽

Low Temperature Stress ◽

Stress Conditions ◽

Pairwise Correlation ◽

Ion Translocation

Abstract Low temperature and soil salinization during cotton sowing and seedling have adverse effects on cotton productivity. Finding an alternative for reducing the low temperature and salt induced damages during the seedling stage of cotton is a challenge for agricultural researchers nowadays. The physiological mechanism of exogenously applied melatonin (MT) on cotton seedlings under low temperature and salt stress is still unclear. The experiment in a phytotron was comprised with two temperature levels of 15°C and 25°C, and 5 MT treatments of 0, 50, 100, 150, 200 µM, and two salinity levels of 0 and 150 mM NaCl stress. Compared with the control treatments (non-salinity stress under 15°C and 25°C), the coupled stress of salt and low temperature reduced cotton seedlings’ biomass and net photosynthetic rate (Pn), aggravated the membrane damage, reduced the potassium (K+) content and increased the sodium (Na+) accumulation in the leaves and roots. Compared with the NaCl-stressed treatment alone, the exogenous foliar applications of 50-150µM MT significantly increased the biomass and gas exchange parameters of cotton seedlings under the coupled salt and low temperature stress conditions. The exogenously applied MT at 50-150µM under the coupled effect of salt and low temperature stress conditions decreased the degree of membrane damage and regulated the activities of the protective enzymes, ion homeostasis, ion transport and absorption of cotton seedlings. The pairwise correlation analysis of each parameter by MT shows that the parameters with higher correlation with MT at 15°C are mainly malondialdehyde (MDA), peroxidase (POD), and catalase (CAT). The most relevant parameters at 25℃ are K+ concentration in leaves (K+-L), K+ concentration in root (K+-R), Na+ concentration in leaves (Na+-L), Na+ concentration in root (Na+-R), Na+ uptake in-root surface (Na+-uptake), K+ ion translocation (K+-translocation). Stepwise linear regression of the above parameters found that MT is more related to MDA at 15°C, and MT is more related to Na+-L at 25°C.

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