持续干旱对油茶叶片及根系生理生化指标的影响

摘要

By the natural drying method to control water gradient,the photosynthetic pigments in leaves and the MDA, proline,soluble sugar,soluble protein,superoxide dismutase,peroxidase,peroxide catalase physiological and biochemi﹣cal indices in leaves and roots (D≤2 mm)of two﹣year﹣old Camellia oleifera′Xianglin 52′grafted seedling were investiga﹣ted with pot experiment simulating continuous drought. The results showed that:with the development of drought stress, the photosynthetic pigment was decreased (P<0. 05). MDA,proline and soluble sugar content were increased in leaves and roots (P<0. 05). Leaf soluble protein content decreased constantly (P<0. 05),soluble protein content in root in﹣creased after the first drop (P<0. 05). SOD activity raised constantly in leaves and roots (P<0. 05),then POD and CAT were higher before the tendency of the lower (P<0. 05). During the experiment,when the soil water content was higher than 30. 6% after re﹣watering,C. oleifera could grow back to normal,when soil water content lower than 21. 1%after re﹣watering,it could not resume normal growth.%以“湘林52”2年生油茶嫁接苗为材料，采用盆栽的试验方法，利用自然干燥法获得控水梯度，测定持续干旱条件下油茶苗叶片光合色素，叶片及根系（D≤2 mm）丙二醛、脯氨酸、可溶性糖、可溶性蛋白、超氧化物歧化酶、过氧化物酶和过氧化氢酶生理生化指标，研究其对干旱胁迫的生理响应。结果表明：随着干旱程度的增加，叶片光合色素含量持续降低（P＜0.05）；叶片及根系丙二醛、脯氨酸和可溶性糖含量均持续增加（P＜0.05），叶片可溶性蛋白含量持续降低（P＜0.05），根系可溶性蛋白含量先增加后下降（P＜0.05）；叶片及根系超氧化物歧化酶活性持续增加（P＜0.05），过氧化物酶和过氧化氢酶活性均呈先升高后降低的变化趋势（P＜0.05）。当土壤相对含水量高于30.6％时，复水后油茶苗能恢复正常生长；当土壤相对含水量低于21.1％时，复水后油茶苗不能恢复正常生长。