Wheat cultivars differing in heat tolerance show a differential response to monocarpic senescence under high-temperature stress and the involvement of serine proteases

2009 ◽  
Vol 47 (4) ◽  
pp. 536-547 ◽  
Author(s):  
S. Chauhan ◽  
S. Srivalli ◽  
A. R. Nautiyal ◽  
R. Khanna-Chopra
Author(s):  
V. Jaldhani ◽  
D. Sanjeeva Rao ◽  
P. Beulah ◽  
B. Srikanth ◽  
P. R. Rao ◽  
...  

Aims: To assess heat-induced PSII damage and efficiency in eight promising backcross introgression lines (BC2F6) of KMR-3R/N22 possessing qHTSF1.1 and qHTSF4.1. Study Design:  Randomized Complete Block Design (RCBD) with three replications. Place and Duration of Study: ICAR-Indian Institute of Rice Research, Hyderabad India during wet/rainy (Kharif) season 2018. Methodology: Eight ILs (BC2F6) and parents were evaluated for heat tolerance. The high- temperature stress was imposed by enclosing the crop with a poly cover tent (Polyhouse) just before the anthesis stage. The fluorescence parameters viz., maximum efficiency of PSII photochemistry (Fv/Fm), Electron transport rate (ETR), effective PSII quantum yield (ΦPSII), coefficient of photochemical quenching (qP) and coefficient of non-photochemical quenching (qN) were measured under ambient and high-temperature stress. Results: The heat-tolerance potential of ILs was assessed in terms of PSII activity. The results indicated that significant differences were observed between treatments (T), genotypes (G) and the interaction between T × G.  The physiological basis of introgressed QTLs controls the spikelet fertility by maintaining the productive and adaptive strategies in heat-tolerant QTL introgressed lines with stable photosynthetic apparatus (PSII) under high-temperature stress. Conclusion: The Fv/Fm ratio denotes the maximum quantum yield of PSII. The heat-tolerant QTL introgressed lines exhibited stable photosynthetic apparatus (PSII) and noted better performance under high-temperature stress. They may be used as donors for fluorescence traits in breeding rice for high-temperature tolerance.


Author(s):  
Syed Bilal Hussain ◽  
Ali Bakhsh ◽  
Muhammad Zubair

A comparison was made of the physiological and morphological differences between Inqlab-91 (hexaploid) and Langdon (tetralpoid) wheat genotypes in response to high temperature stress applied at third leaf stage of growth. Electrolytes leakage technique was used to detect differences in the heat sensitivities of leaves of Inqlab-91 and Langdon. This method showed that at both 35 or 40°C Inqlab-91 was more heat tolerant than Langdon.


2020 ◽  
Vol 47 (5) ◽  
pp. 440 ◽  
Author(s):  
Syed Adeel Zafar ◽  
Amjad Hameed ◽  
Muhammad Ashraf ◽  
Abdus Salam Khan ◽  
Zia-ul- Qamar ◽  
...  

Climatic variations have increased the occurrence of heat stress during critical growth stages, which negatively affects grain yield in rice. Plants adapt to harsh environments, and particularly high-temperature stress, by regulating their physiological and biochemical processes, which are key tolerance mechanisms. The identification of heat-tolerant rice genotypes and reliable selection indices are crucial for rice improvement programs. Here, we evaluated the response of a rice mutant population for high-temperature stress at the seedling and reproductive stages based on agronomic, physiological and molecular indices. Estimates of variance components revealed significant differences (P < 0.001) among genotypes, treatments and their interactions for almost all traits. The principal component analysis showed significant diversity among genotypes and traits under high-temperature stress. The mutant HTT-121 was identified as the most heat-tolerant mutant with higher grain yield, panicle fertility, cell membrane thermo-stability (CMTS) and antioxidant enzyme levels under heat stress. Various seedling-based morpho-physiological traits (leaf fresh weight, relative water contents, malondialdehyde, CMTS) and biochemical traits (superoxide dismutase, catalase and hydrogen peroxide) explained variations in grain yield that could be used as selection indices for heat tolerance in rice during early growth. Notably, heat-sensitive mutants accumulated reactive oxygen species, reduced catalase activity and upregulated OsSRFP1 expression under heat stress, suggesting their key roles in regulating heat tolerance in rice. The heat-tolerant mutants identified in this study could be used in breeding programs and to develop mapping populations to unravel the underlying genetic architecture for heat-stress adaptability.


2006 ◽  
Vol 192 (2) ◽  
pp. 111-120 ◽  
Author(s):  
H. Tewolde ◽  
C. J. Fernandez ◽  
C. A. Erickson

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2110
Author(s):  
Kuan-Hung Lin ◽  
Tse-Yen Lin ◽  
Chun-Wei Wu ◽  
Yu-Sen Chang

High-temperature stress is a major risk to fresh-market Salvia production, and heat intolerance is a major constraint in sage cultivation, particularly during the hot summer season. Previously, we investigated heat tolerance in five common-market cultivars of sage plants using leaf relative injury (RI) values and found that S. elegans Vahl (SE) and S. officinalis L. (SO) were the most and least heat-tolerant species, respectively. The exogenous applications of salicylic acid (SA) and calcium chloride (CaCl2) to alleviate heat stress in various species have been extensively studied, but reports of the effects of SA and CaCl2 treatments on the heat tolerance of sage plants are scarce. The objective of this study was to investigate how SA and CaCl2 affect the physiology and morphology of SE and SO plants under high-temperature conditions. Potted plants were pretreated with SA (0, 100, 200, 400, and 800 μM) and CaCl2 (0, 5, 10, and 15 mM), alone and combined, exposed to 55 °C and 80% humidity for 30 min, then placed in an environment-controlled chamber at 30°C for three days and evaluated for changes in phenotypic appearance, RI, spectral reflectance, and chlorophyll fluorescence indices at different time intervals. Plants watered without chemical solutions were used as controls. Our results show that the growth of SO plants pretreated with SA and CaCl2 was more robust, compared with control plants, which were considerably affected by heat stress, resulting in brown, withered leaves and defoliation. The effects of the combined applications of SA (100 μM) and CaCl2 (5 mM) to SO plants were superior to control plants in increasing values of soil-plant analysis development (SPAD), normalized difference vegetation index (NDVI), and the maximal quantum yield of photosystemII photochemistry (Fv/Fm), while reducing RI%. Furthermore, SO plants exhibited higher SPAD and Fv/Fm values and lower RI% than SE plants in combined treatments at all time intervals after heat stress, implying that different genotypes displayed variations in their SPAD, Fv/Fm, and RI%. Thus, a combined treatment of 100 μM of SA and 5 mM of CaCl2 is effective and beneficial to plant appearance and ability to ameliorate heat stress. These indices can be used as indicators to characterize the physiology of these plants and applied on a commercial scale for informing the development of rapid and precise management practices on bedded sage plants grown in plant factories to achieve maximum market benefit.


Author(s):  
Manu Priya ◽  
Aditya Pratap ◽  
Debjoti Sengupta ◽  
Kadambot H.M Siddique ◽  
N.P. Singh ◽  
...  

2020 ◽  
Author(s):  
Susan Yvonne Jaconis ◽  
Warren C Conaty ◽  
Alan J. E. Thompson ◽  
Shanna L Smith ◽  
Chiara Trimarchi ◽  
...  

Abstract Background Susceptibility of cotton to heat stress in cotton production systems is a major concern for breeding programs. It is hypothesised that in order to maintain or improve cotton yields and quality in sub-optimal future climates, the negative effects of high temperature stress must be mitigated. To address this need, a fast and effect way of quantifying thermotolerant phenotypes is required. Triphenyl tetrazolium chloride (TTC) based enzyme viability testing following high temperature stress can be used as a heat tolerance phenotype. This is because when live cells encounter a TTC solution, TTC undergoes a chemical reduction producing a visible, insoluble red product called triphenyl formazan, that can be quantified spectrophotometrically. However, existing TTC based cell viability assays cannot easily be deployed at the scale required in a crop improvement program. Results In this study, a heat stress assay (HSA) based on the use of TTC enzyme viability testing has been refined and improved for efficiency, reliability, and ease of use through four experiments. Sampling factors which may influence assay results such as leaf age, plant water status, and short-term cold storage were also investigated. Experiments conducted in this study have successfully down scaled the assay and identified an optimal sampling regime, enabling measurement of large segregating populations for application in breeding programs. The optimal durations of leaf disc exposure to TTC and the subsequent extraction of the formazan product in ethanol were identified as 16 h and 13 h, respectively; leading to enhanced clarity of assay results. Conclusions These improvements in the methodology provide a new level of confidence in results, ensuring applicability of the assay to a breeding program. The improved HSA methodology is important as it is proposed that long-term improvements in cotton thermotolerance can be achieved through concurrent selection of superior phenotypes based on the HSA and yield performance in hot environments. Additionally, a new way of interpreting both heat tolerance and heat resistance were developed to differentiate genotypes that perform well at the time of a heat stress event and those that maintain a similar level of performance to a non-stressed control.


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