Physiological Response Of Maize Varieties With Different Drought Resistance During Seedling Stage In The Process Of Drought And Rehydration

Drought and rehydration is always a continuous process in agricultural production. Drought resistance and recovery capacity are significantly different among different plants and different varieties of the same plant. For crops, there is a rapid growth upon stress release and a partial growth recovery upon the onset of stress. Hence, recovery capacity maybe more important to plants after rehydration. To understand the reasons of the existence of such differences and the relation between drought resistance and recovery capacity is important for learning the mechanisms of drought resistance of plants, and breeding for drought resistance varieties.The pot experiment was conducted by weighing to control water content, and imitated drought condition, studied the growth and physiological response of the 10 maize varieties during drought and rehydration. Compared the differences of comprehensive drought resistance, drought resistance and recovery capacity of the 10 maize varieties, analyzed the relation between the physiological response and drought resistance & recovery capacity, The main conclusions are as follows: 1. Drought resistance and recovery capacity of the 10 maize varieties during drought and rehydrationDrought decreased the shoot dry weight of the 10 maize varieties. We used the ratio of shoot dry weight and the contrast to indicate the drought resistance, the drought resistance of the 10 maize varieties from strong to weak was: Liangyu99 male parent, Limin33 female parent, Limin33 male parent, inbred line83-1, Liangyu66 female parent, P1, Liangyu99 female parent, Liangyu66 male parent, P3, Zhengdan958; The recovery capacity of the 10 maize varieties from strong to weak was: P3, inbred line83-1, Zhengdan958, Limin33 male parent, Liangyu99 male parent, P1, Liangyu66 male parent, Liangyu99 female parent, Limin33 female parent, Liangyu66 female parent. Drought resistance and recovery capacity are consistent. 2. Physiological responses of the 10 maize varieties after drought and rehydrationDrought decreased shoot dry weight, plant height, leaf relative water content, water potential, osmotic potential, photosynthetic rate, transpiration rate, stomatal conductance, chlorophyll content, Fv/Fm and YII; Drought increased H2O2 content, MDA content, and starch content; NPQ, total nitrogen content, carotenoid content and soluble sugar content showed no apparent rule. After rehydration, the indexes above recovered compared to contrast, some of them even displayed over compensation effects at the physiological level. 3. The relation between the physiological characteristics and drought resistanceCorrelativity between comprehensive drought resistance and drought resistance was not obvious, but showed obvious correlativity with recovery capacity(r=0.9111*).We analyzed the correlativity between physiological characteristics and drought resistance, recovery capacity and comprehensive drought resistance, and found that chlorophyll content and the drought resistance presented obvious negative correlation(r=-0.6760*), and positive correlation with comprehensive drought resistance(r=0.6866*), and also showed certain relevance with recovery capacity(r=0.5520), but the other physiological characteristics showed no obvious correlation with drought resistance, recovery capacity and comprehensive drought resistance.In conclusion, drought resistance and recovery capacity are important to comprehensive drought resistance. Both strong drought resistance(like Liangyu99 male parent) and strong recovery capacity(like P3) may lead to a strong comprehensive drought resistance. The recovery after rehydration is a rapid process. Reduce the adverse effect of drought on plant is the basis of rapid recovery after rehydration. The rapid repairmen of the damage that drought made may lead to a strong recover capacity. Obvious correlations were showed between the chlorophyll content and drought resistance together with comprehensive drought resistance. Chlorophyll content can be used as an index to evaluate drought resistance and comprehensive drought resistance.