模拟干旱环境下毛竹对伐桩注水的生理响应

Physiological responses of Phyllostachys edulis to water storage in their stumps with a simulated drought environment

为了解干旱环境下增加注水伐桩后毛竹Phyllostachys edulis的生理响应,为气候变化背景下毛竹的适应性经营及节水灌溉提供理论参考。采用对毛竹林地面覆盖薄膜模拟干旱环境的方法,设置ck(0个伐桩注水)、T_1(12个伐桩注水)和T_2(18个伐桩注水)等3种毛竹林伐桩注水处理,并对1年生毛竹叶片净光合速率、蒸腾速率、光合色素含量、膜脂过氧化和抗氧化系统进行测定。结果表明:处理30 d时,T_1处理与ck相比毛竹叶片净光合速率、蒸腾速率、光合色素质量分数、膜脂过氧化和抗氧化系统的差异不显著(P>0.05),仅毛竹叶片丙二醛(MDA)质量摩尔浓度和超氧化物歧化酶(SOD)活性出现显著降低(P<0.05)。随着模拟干旱环境时间的延长,对毛竹叶片净光合速率、蒸腾速率、光合色素质量分数、膜脂过氧化和抗氧化系统的影响逐渐显现,至处理90 d时,除叶片类胡萝卜素质量分数无显著差异外,其他测定指标均达到差异显著水平(P<0.05)。与ck相比,T_2处理在不同时间点对毛竹叶片净光合速率、蒸腾速率、光合色素、膜脂过氧化和抗氧化系统的影响均比T_1处理明显;处理30 d时,仅叶片叶绿素a、相对电导率以及过氧化氢酶(CAT)活性差异不显著(P>0.05);处理90 d时,各项测定指标均显著变化(P<0.05)。毛竹净光合速率、蒸腾速率和叶片光合色素质量分数均与注水伐桩数量正相关,而叶片MDA质量摩尔浓度、相对电导率及SOD、CAT和过氧化物酶(POD)活性均与注水伐桩数量负相关。研究表明:在干旱环境下增加注水伐桩可以显著提高毛竹的光合蒸腾能力和抗氧化能力,改善毛竹生长状况。

To supply a theoretical basis for management an d water-saving irrigation of Phyllostachys edulis（Moso bamboo） in consideration of climate change, a covering film to simulate a drought environment was employed to study physiological responses of 1-year-old Moso bamboo to water storage in their stumps. An experiment with three different irrigation treatments, ck（0 stumps with water storage）, T1（12 stumps with water storage）, and T2（18 stumps with water storage） was established to determine the effect on four variables： leaf photosynthetic rate, photosynthetic pigment, membrane lipid peroxidation, and the antioxidant system. Results for tested physiological parameters during the initial 30 d period showed no significant differences between ck and T1（P〈0.05）; however, in treatment T1 there was a significant decrease（P〈0.05） in malondialdehyde（MDA）content and superoxide dismutase（SOD） activity. With an increase in time of the simulated drought environment, the effects on the four variables gradually appeared. After 90 d, except for carotenoid content, the test physiological indicators of ck had changed significantly（P〈0.05）, and compared to ck, changes for T2 T1 for the four variables. In the initial 30 d, leaf chlorophyll a, relative conductivity, and catalase（CAT） activity were not significantly different（P〈0.05）; but after 90 d, all the test physiological parameters had significantly changed（P〈0.05）. Also, net photosynthetic rate, transpiration rate, and leaf photosynthetic pigment content of Moso bamboo had a positive relationship with the amount of water storage in their stumps; whereas, MDA content, relative conductivity, SOD, CAT, and peroxidase（POD） activity had a negative relationship. This study showed that increased water storage in stumps could improve photosynthesis and transpiration, antioxidant capacity, and growth conditions of Moso bamboo in a drought environment.