Anatomical response of wheat cultivars to drought stress
The study was carried out to investigate the responses of drought stress on wheat tissues. Five wheat cultivars Alta 84 (AL), Atila (AT), Cettia (CE), Norman Bourgluk 2008 (NB) and Seri M82 (SE) were cultivated. Four weeks after planting, healthy plants were subjected to four treatments viz- well-watered (D1), watered daily, drought stress (D2), one weekly watering, drought stress (D3), two weekly watering and drought stress (D4), and three weekly watering. The experiment was a factorial experiment conducted in a completely randomized design (CRD) with three replicates; Transverse section (TS) of the leaves collected were sectioned using microtome, stained and observed under compound microscope. Mesophyll cells, vascular bundles, bundle sheaths and xylem tissues were measured using ocular micrometer. Epidermal peels were prepared to determine the number of stomata and trichomes. When drought stress was imposed (D2, D3 and D4), wheat cultivar Cettia developed larger mesophyll cells, xylem tissues, vascular bundles and bundle sheaths than other cultivars. Thus, larger vascular bundles would facilitate faster movement of water and mineral salts up to the shoot from the root. Cultivar Atila developed higher number of trichomes during drought stress D2 than other cultivars which help to reduce the rate of transpiration of water out of the epidermal leaves. Wheat cultivars Cettia and Atila could be drought tolerant cultivars. Generally, wheat cultivars developed stable stomata number and stomata closure mechanism to cope with drought stress. There was an increase in number of trichomes at D2, D3 and D4 which revealed the ecologically adaptation of wheat plants to drought stress.
Key words: Wheat Cultivars, Drought Stress, Anatomical Structures.