Responses of young wheat plants to moderate heat stress

Abstract

Moderate heat stress may provide protection against a subsequent severe high temperature stress in plants. However, the exact mechanisms of heat acclimation of wheat are still poorly understood. In the present work, two wheat varieties Ellvis and Soissons were exposed to a moderate elevated temperature at 30 °C, and the changes of certain protective mechanisms were investigated. Although the differences in the proline level between the genotypes were not substantial, it was approx. 2-3 times higher in the heat-treated plants than in the controls. After exposure to moderate elevated temperature, the activities of ascorbate peroxidase and catalase were also induced. Similarly, the amount of the free salicylic acid also increased after moderate heat stress, independently on the genotypes. The amount of the main polyamines, namely, putrescine, spermidine, and spermine either did not change or decreased after the same period. However, heat acclimation increased the level of 1,3-diaminopropane, in parallel with a polyamine oxidase gene, TaPAO. While the expression level of the peroxisomal polyamine oxidase gene TaperPAO hardly changed, TaPAO showed a substantial increase after 1 day, especially in Soissons, and at the end of the heat treatment was still significantly higher than in the controls. These suggest that signalling processes related to polyamine metabolisms or salicylic acid-related processes might also contribute to the higher heat tolerance induced by moderate heat stress. The variations in recorded measurements were mainly temperature dependent, and the effect of genotype was less pronounced than the effect of moderate heat treatment itself.

Understanding the Role of Gibberellic Acid and Paclobutrazol in Terminal Heat Stress Tolerance in Wheat

“…The compensatory effect of grain filling rate was not adequate to overcome the decrease in duration, leading to a decrease in seed setting and 1,000 grain weight, ultimately causing a significant reduction in yield (Reynolds et al, 2012;Tan et al, 2015). High temperature diverted the photo-assimilates from developing stress tolerance mechanism to survive under stress, which led to a decrease in the availability of photo-assimilates for the development of reproductive organs (Wahid et al, 2007;Janda et al, 2019;Hasanuzzaman et al, 2020). The rate of starch deposition in wheat grains was decreased by >30% at temperatures between 30 and 40 • C, with the early grain filling being the most critical stage (Stone and Nicolas, 1994).…”

Accelerating the Development of Heat Tolerant Tomato Hybrids through a Multi-Traits Evaluation of Parental Lines Combining Phenotypic and Genotypic Analysis

“…Since the HT also can enhance the proliferation of important vectors and negatively affect the immunity response of tomato plants [26], causing the increase of plant diseases due to ubiquitous pathogens or vector-mediated infections [27], the raising use of chemicals in agriculture would be required, thus favoring environmental pollution and the onset of pest resistances [28].…”

The alleviating effect of exogenous polyamines on heat stress susceptibility of different heat resistant wheat (Triticum aestivum L.) varieties

“…SOD converts ROS into H 2 O 2 and O 2 , while CAT and POD convert H 2 O 2 into H 2 O 4,9 . Nevertheless, growth and development will be threatened when the stress exceeds its regulatory range 10,11 . At present, in the field of production the main way to enhance the tolerance of wheat to high temperature stressis to select heat-resistant wheat varieties through the accumulation of heat-resistant genes 12,13 , but this process takes a long time and is greatly affected by the environment 14 .…”