Effect of Drought Stress and Rewatering on Root Morphological Characteristics and Leaf Anatomical Structure of Foxtail Millet
A drought-resistant variety Jigu 16 and a drought-sensitive variety Lugu 1 were used as materi-als to study the response of leaf and root morphological indicators to drought stress and rewatering with pot ex-periment.Drought stress treatment was performed by stop watering 15 days after sprout,and then rewatering 9 days later.The results were as follows.(1)Compared with normal water supply treatment(CK),the number of lateral roots and root tips and the root volume of the two varieties decreased significantly under drought stress.After rewatering,the number of root tips of Jigu 16 increased significantly,while that of Lugu 1 further decreased(P<0.05).The number of lateral roots of Jigu 16 increased more than that of Lugu 1 after rewater-ing.(2)Under drought stress,the area of bulliform cells in leaves and the leaf thickness of the two varieties decreased.After rewatering,the bulliform cell area of Jigu 16 recovered to the similar level of CK,while that of Lugu 1 was still significantly smaller compared to CK(P<0.05).(3)Under drought stress,the stomatal den-sity in the lower epidermis of Jigu 16 increased,while the stomatal density in the upper epidermis decreased,and the difference was significant(P<0.05)compared with CK;after rehydration,the upper epidermal stoma-tal density increased slightly but was still lower than CK,and that in lower epidermal stomatal density de-creased to CK level.Stomatal density of upper and lower epidermis of Lugu 1 decreased after drought stress.Af-ter rehydration,the upper epidermal stomatal density still decreased slightly,but the lower epidermal stomatal density increased significantly,slightly higher than CK.There was no significant change in stomatal length in upper and lower epidermis of Jigu 16 after drought stress.After rehydration,it increased significantly compared with CK and drought treatment.Stomatal length of upper epidermis of Lugu 1 decreased significantly(P<0.05).After rehydration,it still decreased slightly,but the difference was not significant compared with drought treatment.The stomatal length of lower epidermis decreased but the difference was not significant com-pared with CK,and continued to increase after rehydration,which was significantly higher than CK.Jigu 16 showed stronger morphological adaptability and self-regulation ability under drought stress,and its drought tol-erance was stronger than Lugu 1.
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