Abstract: A pot experiment was conducted to study the effects of simulated moderate drought in whole growth period on the grain yield and root physiological traits of drought-tolerant maize variety JK 628 and drought-sensitive maize variety ND-95. Compared with the control, the grain yield of JK-628 and ND-95 under the stress of moderate drought was decreased by 33.7% and 62.3%, respectively. Under drought stress, the root biomass of the two varieties decreased, with the maximum value appeared ahead. The root/shoot ratio of JK-628 increased at early growth stage but decreased at late growth stage, while that of ND-95 increased all along. ND-95 had a larger decrement of root activity than JK-628. The root SOD activity in drought stress plants was higher in prophase but lower in anaphase, compared with that in the control, and the time of SOD activity begun to lower was later for JK-628 than for ND-95. The root MDA content in drought-stress plants was increased, and the increment was much higher for ND-95 than for JK-628. In addition, the root soluble protein content in drought-stress plants was decreased, and ND-95 had a larger decrement than JK-628. In a word, under drought stress, the root activity, SOD activity, and soluble protein content of JK-628 were higher than those of ND-95, which could slow down the root aging process and prolong the root functional period, possibly being one of the important factors of getting high yield of drought-tolerant maize under drought stress.

Key words: maize, drought tolerance, yield, root traits, agricultural heat resource, crop cultivation zone, cotton, potato, Shanxi.