Differences in physiological characteristics between two wheat cultivars exposed to field water deficit conditions

Abstract

We investigated various physiological characteristics of two wheat (Triticum aestivum L.) cultivars differing in drought tolerance, i.e., Shannong16 (a drought-tolerant cultivar) and Weimai8 (a high-yield wheat cultivar under well-watered conditions), under field drought conditions. The experiments were conducted over a two-year period. Drought stress (DS) was imposed by controlling irrigation and sheltering the plants from rain. Compared with Weimai8, Shannong16 exhibited the better water balance, the higher osmotic adjustment, the slower degradation of chlorophyll, and the higher net photosynthetic rate under drought-stress conditions. At the same time, we observed that Shannong16 maintained more integrated chloroplast and thylakoid ultrastructure in flag leaves than Weimai8 under field drought stress. The different levels of antioxidant competence, indicated by MDA content, antioxidant enzyme activities, and the level of superoxide radicals observed in the two wheat cultivars may be involved in the different levels of drought resistance of these cultivars.