Water stress-induced changes in morphology and anatomy of flag leaf of spring wheat

Abstract

Flag leaves of wheat (drought hardened and non-hardened) were examined by light microscopy to determine whether the differences in leaf anatomy could be related to the known differences in dehydration tolerance. Plants exposure to water stress during tissue differentiation of flag leaves resulted in an irreversible reduction of leaf area and thickness, increased frequencies of stomata and higher number of bulliform cells with simultaneous decrease in number of intermediate veins and an increase in the share of the cell walls in total cell volume. The smaller leaf thickness was due to a diminished number of mesophyll layers and a decreased size of mesophyll cells. Such altered leaf anatomy indicated development of leaf xerophily. It was found that the irreversible changes in anatomy of wheat flag leaves play a decisive role in acquiring drought tolerance during wheat acclimation to drought.