Studies On The Physiological Adaptability Of Two Aliena Species Under Salt And Moisture Stress

Quercus L. is a large and important genus of subtropical, temperate and warm temperate forests. It is the largest genus in the Fagaceae, and distributed throughtout Asia, America and Europe extensively. It also occupies the important position in the recovery of the world forest vegetation and the construction of the landscape. But now as one of the distributed centers in the world, the wild plant resource of oaks is utilized directly in China. The propagation and cultivation technical research of introduction and acclimatization in oaks is the key to sustainable utilization. There are two parts in my thesis :1.It has been studied on the physiology response of two years young seedlings of Q. aliena var. pekingensis and Q. aliena.var. acuteserrata in different concentrations of NaCl. The result showed that both varieties had the salinity resistance in 1-3‰concentrations of NaCl. The total leaf area, fresh weight and dry weight of two varieties fell down significantly, and the relative permeability of plasma membrance in leaves of two varieties of Q. aliena changed oppositely. Q. aliena var. acuteserrata variate greater than Q. aliena var. pekingensis. The SOD activity, proline and soluble protein contents of Q. aliena var. acuteserrata were much lower than Q. aliena var. pekingensis. More K~+ conveyed to stems and leaves, but more Na~+ stayed in root system. Q. aliena var. pekingensis could maintain more higher K~+ content, and the K~+/Na~+ ratio fell more lower. The two years young seedings of Q. aliena var. pekingensis and Q. aliena var. acuteserrata were treated with different concentrations of NaCl. The result showed that NaCl stress decreased plant total leaf area, fresh weight, dry weight, photosynthetic rate, stomatal conduction, stomatal limit, chlorophyll content and quantum yield of PSⅡobviously.However, the initial fluoreslence and photochemical efficiency of PSⅡwas not affected by salt stress. The plant growth of Q. aliena var. pekingensis was less affected by salt stress than Q. aliena var. acuteserrata, the photosynthetic rate was less decreased and the photosynthetic apparatus was less injured by salt stress than Q. aliena var. acuteserrata. So the salinity resistance of Q. aliena var. pekingensis is much higher than Q. aliena var. acuteserrata.2.This stuty was related on the adaptability of two years young seedlings of Q. aliena var. pekingensis and in different concentrations of water. The result showed that the increment and biomass of Q. aliena.var.acuteserrata was higher than Q. aliena var. pekingensis's obviously in 67% water condition, but the state was opposite in 33% and 100% water condition. Their relative water and soluble sugar content in leaves was not variant notable in water stress. The electrotic leakage and MDA content was lowwer and the proline was higher in leaves of Q. aliena var. pekingensis than Q. aliena var. acuteserrata in water stress. So, the water compatibility of Q. aliena var .pekingensis was very extensive.