Stigma Functionality and Fertility Are Reduced by Heat and Drought Co-stress in Wheat

Abstract

As a consequence of climate change, unpredictable extremely hot and dry periods are becoming more frequent during the early stages of reproductive development in wheat (Triticum aestivum L.). Pollen sterility has long been known as a major determinant of fertility loss under high temperature and water scarcity, but it will be demonstrated here that this is not the exclusive cause and that damage to female reproductive organs also contributes to losses of fertility and production. Changes in the phenology, morphology, and anatomy of female reproductive cells and organs, in the ROS and RNS generation of stigmatic papilla cells, and in fertility and yield components in response to simultaneous high temperature and drought at gametogenesis were studied in two wheat genotypes with contrasting stress responses. The combination of high temperature (32/24°C) and total water withdrawal for 5 days at gametogenesis altered the phenology of the plants, reduced pollen viability, modified the morphology and the anatomy of the pistils, enhanced the generation of ROS and RNS, intensified lipid peroxidation and decreased the NO production of stigmatic papilla cells, all leading to reduced fertility and to production loss in the sensitive genotype, depending on the position of the floret on the spike. Reduced functionality of female and male reproductive parts accounted for 34% and 66%, respectively, of the total generative cell- and organ-triggered fertility loss.

Novel Alleles for Combined Drought and Heat Stress Tolerance in Wheat

“…Grain number was mostly increased by the same allele as grain weight in both GWAS and NILs, indicating an important factor under post-anthesis drought and heat stress. Grain number is known to be affected by pre-anthesis stress (Fabian et al, 2019) but has also been found to be decreased by postanthesis stress (Prasad et al, 2011;Qaseem et al, 2018). Grain number, in our experiments, accounted for only well-filled grains Alleles for Drought and Heat Tolerance in Wheat (i.e., grains of size > 2.0 mm).…”

Unique features of the grapevine VvK5.1 channel support novel functions for outward K+ channels in plants

“…The main method of pollination in these domesticated vines is self-fertilization. However, in an inflorescence, the percentage of ovaries yielding fruit is strongly variable, and is affected by different factors including environmental changes such as light, temperature, and water stress (Lecourieux et al , 2017; Fábián et al ., 2019), but also vineyard management and grape variety features (Dry et al , 2010). Indeed, low fruit set can limit crop yield, resulting in losses to grape and wine production.…”

Mitigating water stress on wheat through foliar application of silicon

“…Water stress and high temperature are the exclusive cause that damages the female reproductive organs which leads to losses of fertility and production. Therefore, pollen sterility is not the major determinant of fertility loss under high temperature and water scarcity (Fábián et al, 2019). In wheat, higher temperature and water stress collectively reduced 66% to 93% rate of photosynthetic compared with non-stress conditions.…”