Drought, high temperature, and their combination affect ultrastructure of chloroplasts and mitochondria in wheat (Triticum aestivumL.) leaves

Abstract

Plants experience a number of limiting factors, as drought and heat, which are often coinciding stress factors in natural environment. This study evaluated the changes in mesophyll cell ultrastructure in the leaves of two varieties of winter wheat (Triticum aestivum L.), differing in their drought tolerance, under individual or combined drought and heat treatment. Although the individual stress factors affected leaf ultrastructure, the damaging effect of the combined drought and heat was more pronounced and manifested certain differences between genotypes. Chloroplasts and mitochondria were affected in a variety-specific manner under all adverse treatments. The organelles of the drought-tolerant Katya were better preserved than those in the sensitive variety Sadovo. Leaf ultrastructure can be considered as one of the important characteristics in the evaluation of the drought susceptibility of different wheat varieties.

A morpho-physiological approach differentiates bread wheat cultivars of contrasting tolerance under cyclic water stress

“…At the same time, however, an outstanding peak of conductivity was observed in the other sensitive genotype (GK Élet), while the best performing Plainsman V showed the lowest level of cellular injury throughout the experiment. A correlation between drought sensitivity and cellular injuries in wheat varieties has also been noted by Grigorova et al (2012). In their report, better preservation of organelles was described in a drought-tolerant wheat variety compared to a sensitive cultivar upon water shortage or combined water and heat stress.…”

Effects of individual and combined heat and drought stress during seed filling on the oxidative metabolism and yield of chickpea (Cicer arietinum) genotypes differing in heat and drought tolerance

“…Drought and heat stress are two major environmental factors that can markedly affect plant productivity (Lipiec et al 2013). These two stresses often coincide to severely limit crop growth and productivity (Prasad et al 2008;Grigorova et al 2012;Lipiec et al 2013). In combination, drought stress and heat stress affect the yield of many crops more than the individual effects of each stress (Rollins et al 2013).…”

Selection and Breeding of Suitable Crop Genotypes for Drought and Heat Periods in a Changing Climate: Which Morphological and Physiological Properties Should Be Considered?

“…Depending on drought intensity, multiple abnormalities occur in cellular organelles and structures [112,113]. Under drought, the leaf mesophyll cells contain chloroplasts and mitochondria of irregular shape and size [114][115][116][117]. The chloroplast ultrastructure is compromised, manifested by swollen granal compartments, disrupted chloroplast membranes, accumulation of plastoglobuli and a reduced size/lack of starch grains [116,117].…”

“…Under drought, the leaf mesophyll cells contain chloroplasts and mitochondria of irregular shape and size [114][115][116][117]. The chloroplast ultrastructure is compromised, manifested by swollen granal compartments, disrupted chloroplast membranes, accumulation of plastoglobuli and a reduced size/lack of starch grains [116,117]. Drought-affected mitochondria are mostly enlarged, often devoid of cristae, and possess large electron-transparent areas [116].…”

“…Leaf cell organelles in the drought-tolerant genotypes are better preserved, whereas the chloroplast and mitochondrial structure of the sensitive cultivars is severely disorganized, which leads to organelle dysfunction. All the visual structural alterations can be easily converted into very informative numerical data by a quantitative morphometric analysis [26,116,117]. Therefore, the intactness of subcellular structures could be considered as an additional trait, contributing to crop improvement and could serve as a reliable stress marker in the selection of sustainable crop genotypes.…”