Study On The Physiological Responds To Drought Stress Of Castanea Mollissima BL. Cultivars In North China

The variation of physiological activated substance of Chinese chestnet,such as Electrical conductivies, Malondialdenyde, SOD activities, POD activities, EndohormoneABA, Energy of seedlings etc were measured under water stress. Drought-resistance of the variation Chinese chestnet of each time of water stress were compared.The relationships between water use efficiency and leaf indices in Castanea mollissima BL.were studied by measuring the stomatal density,ratio of stockade tissue to sponge tissue, carbon isotope ratio, stomatal conductance and water use efficiency in 19 cultivars of Castanea mollissima BL. The stem sap flow of Castanea mollissima BL.variety were studied. The result showed that During water-stress,the activieties of SOD and POD increased firstly,then decreased;The praline in leaves increased. Malondiadehyde content and Plasma mambrace perneality in leaves also increased. Endohormone ABA in leaves increased during the water-stress.When the seedling renewed watering, Endohormone ABA decreased to the ordinary leavel.During the water-stess the Energy of seedlings decreased.When the soil moisture content arrived 1.87%,the rape seedling of Castanea mollissima BL.died. Plasma mambrace pernealityand EndohormoneABA was the best physiological activated substance.There was no significant correlation between stomatal density and water use efficiency(r=0.282),while positive correlations were found between stockade tissue/sponge tissue, carbon isotope ratio, and stomatal conductance, the correlation coefficients were 0.762, 0.604 and 0.726, respectively. The methods to depilate leaf epidermis hair were studied. The best way was erasing hairs with eraser. The method of nail polish imprint in Castanea mollissima BL.is also discussed. The stomatal density in Castanea mollissima BL.was 740 to 980 stoma/mm2, a high value compared to other species. This was the first report on the study of stoma characteristics in Castanea mollissima BL.The speed of stem sap flow of Castanea mollissima BL.were fast in Yanshanduanzhi and slowest inZunyu. The daily accumulated sap flow amounts of were most in Yanshanzaofeng and lest in Zunyu.