scholarly journals Physiological responses and post-stress recovery in field-grown maize exposed to high temperatures at flowering

2019 ◽  
pp. 2053-2061
Author(s):  
Nicolás Neiff ◽  
Edmundo L. Ploschuk ◽  
Oscar R. Valentinuz ◽  
Fernando H. Andrade
Keyword(s):  
Heat Stress ◽  
High Temperatures ◽  
Cell Injury ◽  
Co2 Concentration ◽  
Physiological Traits ◽  
Maximum Efficiency ◽  
Maize Cultivars ◽  
Temperature Regimes ◽  
Internal Co2 ◽  
Heat Stress Tolerance

Heat stress affects physiological traits and biomass production in major crops, including maize. We researched the responses of maximum efficiency of photosystem II (Fv/Fm), relative cell injury (RCI), stomatal conductance (gs), internal CO2 concentration (Ci), leaf photosynthesis (CER), and crop growth rate (CGR) in two maize cultivars exposed to high temperatures around silking (R1) under field conditions. Temperature regimes (i.e. control and heat) were performed during the pre-silking (–15d R1 to R1) and post-silking (R1+2d to R1+17d) periods. In the heat treatments, polyethylene shelters were used in order to increase daytime temperatures around midday (from 10 A.M. to 2 P.M.) during each period (i.e., pre- and post-silking). In the control treatments, the shelters remained open during the entire growing season. Gas exchange variables, Fv/Fm and relative cell injury (RCI) were measured on ear leaves. CGR was estimated based on biomass samples. CER and Fv/Fm presented maximum reductions at the end of the daytime heating. However, 30 min after the shelters were reopened, Fv/Fm of heated leaves reached values similar to controls, which were closely linked to CER recoveries. RCI was negatively associated with Fv/Fm, and cell injury increased gradually as heating continued. Ci was unaffected by heat treatment, indicating that gs was not the primary cause of CER reduction. Heat stress decreased CGR, and the reduction was positively associated with CER and Fv/Fm in both heating periods. We attempted to scale from cell to crop level and identify some physiological traits that could be helpful in breeding programs for heat stress tolerance.

scholarly journals Morpho-physiological traits associated with heat stress tolerance in tropical maize (Zea mays L.) at reproductive stage

2019 ◽  
Vol 13 ((04) 2019) ◽  
pp. 536-545 ◽  
Author(s):  
Jewel Jameeta Noor ◽  
M.T. Vinayan ◽  
Shahid Umar ◽  
Pooja Devi ◽  
Muhammad Iqbal ◽  
...  
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Stress Tolerance ◽  
Inbred Lines ◽  
Physiological Traits ◽  
Optimal Temperature ◽  
Tropical Maize ◽  
Important Trait ◽  
Heat Stress Tolerance ◽  
Secondary Traits

Heat stress resilience has emerged as an important trait in maize hybrids targeted for post–monsoon spring cultivation in large parts of South Asia and many other parts of the tropics. Selection based on grain yield alone under heat stress is often misleading, and therefore an approach involving stress-adaptive secondary traits along with grain yield could help in the development of improved, stable heat stress tolerant cultivars. We attempted to identify reliable and effective secondary traits associated with heat stress tolerance in tropical maize and sources of heat stress tolerant germplasm. A panel of 99 elite maize inbred lines representing the wider genetic diversity of tropical maize and a set of 58 elite hybrids were phenotyped under natural heat stress and optimal temperature for grain yield and 15 secondary traits including 10 morpho-physiological traits and 5 yield attributes. Evaluation under natural heat stress was done during the spring season by adjusting the planting date so that the complete reproductive stage (from tassel emergence to late grain filling) was exposed to heat stress. The optimal temperature trial was planted during the monsoon season with no exposure to heat stress at any crop stage. Heat stress significantly affected most of the observed traits. Among the traits studied two yield attributing traits, i.e.- ears per plant (EPP) and kernel per row (KPR), and three morpho-physiological traits, i.e.- chlorophyll content (CC), leaf firing (LF) and tassel blast (TB) were found to be the key secondary traits associated with grain yield under heat stress. In addition, low anthesis-silking internal (ASI) is an important trait that needs to be added in the index selection for heat stress tolerance. The study identified nine promising heat stress tolerant maize inbred lines with desirable secondary traits and grain yield under severe heat stress, which could be used as source germplasm in heat stress tolerance maize breeding program.

scholarly journals Effect of heat stress at anthesis on yield formation in winter wheat  

2017 ◽  
Vol 63 (No. 3) ◽  
pp. 139-144 ◽  
Author(s):  
Hlaváčová Marcela ◽  
Klem Karel ◽  
Smutná Pavlína ◽  
Škarpa Petr ◽  
Hlavinka Petr ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperatures ◽  
Wheat Yield ◽  
Weather Conditions ◽  
Similar Response ◽  
Thousand Grain Weight ◽  
Yield Parameters ◽  
Temperature Regimes ◽  
Response To Temperature ◽  
Yield Formation

Heat stress around anthesis is considered to have an increasing impact on wheat yield under the ongoing climate change. However, the effect of high temperatures and their duration on formation of individual yield parameters is still little understood. Within this study, the effect of high temperatures applied during anthesis for 3 and 7 days on yield formation parameters was analysed. The study was conducted in growth chambers under four temperature regimes (daily temperature maxima 26, 32, 35 and 38°C). In the periods preceding and following heat stress regimes the plants were cultivated under ambient weather conditions. The number of grains per spike was reduced under temperatures ≥ 35°C in cv. Bohemia and ≥ 38°C in cv. Tobak. This resulted in a similar response of spike productivity. Thousand grain weight showed no response to temperature regime in cv. Tobak, whereas in cv. Bohemia, a peak response to temperature with maximum at 35°C was observed. The duration of heat stress had only little effect on most yield formation parameters.  

scholarly journals CaHsfA1d Improves Plant Thermotolerance via Regulating the Expression of Stress- and Antioxidant-Related Genes

2020 ◽  
Vol 21 (21) ◽  
pp. 8374
Author(s):  
Wen-Xian Gai ◽  
Xiao Ma ◽  
Yang Li ◽  
Jing-Jing Xiao ◽  
Abid Khan ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
High Temperatures ◽  
Regulatory Mechanism ◽  
Dynamic Balance ◽  
Transcription Activator ◽  
Glutathione S Transferase ◽  
Class A ◽  
Transgenic Lines ◽  
Heat Stress Tolerance

Heat shock transcription factor (Hsf) plays an important role in regulating plant thermotolerance. The function and regulatory mechanism of CaHsfA1d in heat stress tolerance of pepper have not been reported yet. In this study, phylogenetic tree and sequence analyses confirmed that CaHsfA1d is a class A Hsf. CaHsfA1d harbored transcriptional function and predicted the aromatic, hydrophobic, and acidic (AHA) motif mediated function of CaHsfA1d as a transcription activator. Subcellular localization assay showed that CaHsfA1d protein is localized in the nucleus. The CaHsfA1d was transcriptionally up-regulated at high temperatures and its expression in the thermotolerant pepper line R9 was more sensitive than that in thermosensitive pepper line B6. The function of CaHsfA1d under heat stress was characterized in CaHsfA1d-silenced pepper plants and CaHsfA1d-overexpression Arabidopsis plants. Silencing of the CaHsfA1d reduced the thermotolerance of the pepper, while CaHsfA1d-overexpression Arabidopsis plants exhibited an increased insensitivity to high temperatures. Moreover, the CaHsfA1d maintained the H2O2 dynamic balance under heat stress and increased the expression of Hsfs, Hsps (heat shock protein), and antioxidant gene AtGSTU5 (glutathione S-transferase class tau 5) in transgenic lines. Our findings clearly indicate that CaHsfA1d improved the plant thermotolerance via regulating the expression of stress- and antioxidant-related genes.

scholarly journals Physiological Characterization of Young ‘Hass’ Avocado Plant Leaves Following Exposure to High Temperatures and Low Light Intensity

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1562
Author(s):  
Or Shapira ◽  
Simon Chernoivanov ◽  
Itamar Neuberger ◽  
Shay Levy ◽  
Lior Rubinovich
Keyword(s):  
Heat Stress ◽  
High Temperatures ◽  
Damage Threshold ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Leaf Damage ◽  
Temperature Threshold ◽  
Plant Leaves ◽  
Low Light ◽  
Physiological Characterization

The worldwide demand for avocados has resulted in the planting of millions of young plants each year. However, global warming, resulting in high temperatures, sensed as heat stress, may severely damage these new plantings. The objective of this study was to assess the risks of heat stress on young avocado plants. We aimed to characterize different physiological parameters of young ‘Hass’ plant leaves following exposure to high temperatures under low light (LL) intensity and to pinpoint the temperature threshold for significant heat stress damage in these plants. To this end, young potted plants were subjected to different temperature gradients in a controlled-climate chamber. Minor and severe leaf damage was apparent in plants subjected to the 51 °C and 53 °C treatments, respectively. Minor and vast reductions in optimal quantum yield efficiency of photosystem II (Fv/Fm) values were observed in plants subjected to 51 °C and 53 °C, respectively. Heat stress treatments significantly reduced CO2 assimilation in plants subjected to 49 °C and higher temperatures. Stomatal conductance to water vapour and substomatal internal CO2 concentration were less sensitive to the heat treatments. These results imply that the heat damage threshold for young avocado plants under LL conditions is between 49 °C and 51 °C, whereas at 53 °C, severe and irreversible leaf damage occurs.

scholarly journals Ethylene involvement in the regulation of heat stress tolerance in plants

2021 ◽  
Author(s):  
Peter Poór ◽  
Kashif Nawaz ◽  
Ravi Gupta ◽  
Farha Ashfaque ◽  
M. Iqbal R. Khan
Keyword(s):  
Heat Stress ◽  
Stress Tolerance ◽  
Heat Stress Tolerance

Evaluation of Triticum durum–Aegilops tauschii derived primary synthetics as potential sources of heat stress tolerance for wheat improvement

2021 ◽  
Vol 19 (1) ◽  
pp. 74-89
Author(s):  
Amandeep Kaur ◽  
Parveen Chhuneja ◽  
Puja Srivastava ◽  
Kuldeep Singh ◽  
Satinder Kaur
Keyword(s):  
Heat Stress ◽  
Stress Tolerance ◽  
Hexaploid Wheat ◽  
Aegilops Tauschii ◽  
Grain Filling ◽  
World Population ◽  
Potential Candidate ◽  
Terminal Heat Stress ◽  
Heat Stress Tolerance ◽  
The Impact

AbstractAddressing the impact of heat stress during flowering and grain filling is critical to sustaining wheat productivity to meet a steadily increasing demand from a rapidly growing world population. Crop wild progenitor species of wheat possess a wealth of genetic diversity for several biotic and abiotic stresses, and morphological traits and can serve as valuable donors. The transfer of useful variation from the diploid progenitor, Aegilops tauschii, to hexaploid wheat can be done through the generation of synthetic hexaploid wheat (SHW). The present study targeted the identification of potential primary SHWs to introduce new genetic variability for heat stress tolerance. Selected SHWs were screened for different yield-associated traits along with three advanced breeding lines and durum parents as checks for assessing terminal heat stress tolerance under timely and late sown conditions for two consecutive seasons. Heat tolerance index based on the number of productive tillers and thousand grain weight indicated that three synthetics, syn9809 (64.32, 78.80), syn14128 (50.30, 78.28) and syn14135 (58.16, 76.03), were able to endure terminal heat stress better than other SHWs as well as checks. One of these synthetics, syn14128, recorded a minimum reduction in thousand kernel weight (21%), chlorophyll content (2.56%), grain width (1.07%) despite minimum grain-filling duration (36.15 d) and has been selected as a potential candidate for introducing the terminal heat stress tolerance in wheat breeding programmes. Breeding efforts using these candidate donors will help develop lines with a higher potential to express the desired heat stress-tolerant phenotype under field conditions.

scholarly journals Genotype and Trait Specific Responses to Rapamycin Intake in Drosophila melanogaster

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 474
Author(s):  
Palle Duun Rohde ◽  
Asbjørn Bøcker ◽  
Caroline Amalie Bastholm Jensen ◽  
Anne Louise Bergstrøm ◽  
Morten Ib Juul Madsen ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Stress ◽  
Side Effects ◽  
Protein Kinase ◽  
Stress Tolerance ◽  
Treated Group ◽  
Model System ◽  
Treatment Efficiency ◽  
Evolutionarily Conserved ◽  
Heat Stress Tolerance

Rapamycin is a powerful inhibitor of the TOR (Target of Rapamycin) pathway, which is an evolutionarily conserved protein kinase, that plays a central role in plants and animals. Rapamycin is used globally as an immunosuppressant and as an anti-aging medicine. Despite widespread use, treatment efficiency varies considerably across patients, and little is known about potential side effects. Here we seek to investigate the effects of rapamycin by using Drosophila melanogaster as model system. Six isogenic D. melanogaster lines were assessed for their fecundity, male longevity and male heat stress tolerance with or without rapamycin treatment. The results showed increased longevity and heat stress tolerance for male flies treated with rapamycin. Conversely, the fecundity of rapamycin-exposed individuals was lower than for flies from the non-treated group, suggesting unwanted side effects of the drug in D. melanogaster. We found strong evidence for genotype-by-treatment interactions suggesting that a ‘one size fits all’ approach when it comes to treatment with rapamycin is not recommendable. The beneficial responses to rapamycin exposure for stress tolerance and longevity are in agreement with previous findings, however, the unexpected effects on reproduction are worrying and need further investigation and question common believes that rapamycin constitutes a harmless drug.

HSP70-4 and farnesylated AtJ3 constitute a specific HSP70/HSP40-based chaperone machinery essential for prolonged heat stress tolerance in Arabidopsis

2021 ◽  
pp. 153430
Author(s):  
Tzu-Yun Wang ◽  
Jia-Rong Wu ◽  
Ngoc Kieu Thi Duong ◽  
Chung-An Lu ◽  
Ching-Hui Yeh ◽  
...  
Keyword(s):  
Heat Stress ◽  
Stress Tolerance ◽  
Heat Stress Tolerance ◽  
Prolonged Heat

scholarly journals Overexpression of the Golden SNP-Carrying Orange Gene Enhances Carotenoid Accumulation and Heat Stress Tolerance in Sweetpotato Plants

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 51
Author(s):  
So-Eun Kim ◽  
Chan-Ju Lee ◽  
Sul-U Park ◽  
Ye-Hoon Lim ◽  
Woo Sung Park ◽  
...  
Keyword(s):  
Heat Stress ◽  
Stress Tolerance ◽  
Ipomoea Batatas ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Cauliflower Mosaic Virus ◽  
Carotenoid Content ◽  
35S Promoter ◽  
Storage Roots ◽  
Heat Stress Tolerance

Carotenoids function as photosynthetic accessory pigments, antioxidants, and vitamin A precursors. We recently showed that transgenic sweetpotato calli overexpressing the mutant sweetpotato (Ipomoea batatas [L.] Lam) Orange gene (IbOr-R96H), which carries a single nucleotide polymorphism responsible for Arg to His substitution at amino acid position 96, exhibited dramatically higher carotenoid content and abiotic stress tolerance than calli overexpressing the wild-type IbOr gene (IbOr-WT). In this study, we generated transgenic sweetpotato plants overexpressing IbOr-R96H under the control of the cauliflower mosaic virus (CaMV) 35S promoter via Agrobacterium-mediated transformation. The total carotenoid contents of IbOr-R96H storage roots (light-orange flesh) and IbOr-WT storage roots (light-yellow flesh) were 5.4–19.6 and 3.2-fold higher, respectively, than those of non-transgenic (NT) storage roots (white flesh). The β-carotene content of IbOr-R96H storage roots was up to 186.2-fold higher than that of NT storage roots. In addition, IbOr-R96H plants showed greater tolerance to heat stress (47 °C) than NT and IbOr-WT plants, possibly because of higher DPPH radical scavenging activity and ABA contents. These results indicate that IbOr-R96H is a promising strategy for developing new sweetpotato cultivars with improved carotenoid contents and heat stress tolerance.

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