模拟干旱环境下伐桩注水对毛竹生理特性的影响

[目的]探究模拟干旱环境下注水伐桩对1、2和3年生毛竹生理特性的影响,为气候变化背景下毛竹的适应性经营管理及毛竹林节水灌溉措施的制定提供理论参考。[方法]在毛竹林中选取面积相同(10 m×20 m)的样地9块,以1、2和3年生毛竹为试验材料,采用覆盖薄膜模拟干旱环境,对各样地四周进行挖沟切鞭处理,以阻断周边土壤水分的运输,试验设置CK(0个伐桩注水)、T1(12个伐桩注水)和T2(18个伐桩注水)3个灌水量处理,每个处理均进行3次重复,研究不同数量注水伐桩下3个年龄毛竹的生理响应。[结果]试验表明,在模拟干旱环境下,随着注水伐桩数量的减少,3个年龄毛竹的净光合速率与蒸腾速率显著下降,1、2和3年生毛竹的净光合速率与蒸腾速率最大降幅分别达到74.35%和73.08%、59.14%和36.62%及60.47%和61.54%;毛竹叶片叶绿素a、叶绿素b和类胡萝卜素含量显著下降,1年生和3年生毛竹叶片叶绿素a、叶绿素b和类胡萝卜含量差异均达到显著水平(P0.05),2年生毛竹叶片叶绿素a含量差异显著(P0.05),但叶绿素b和类胡萝卜素含量差异不显著(P0.05),3个年龄毛竹叶片叶绿素a/b差异均不显著(P0.05);毛竹叶片丙二醛(MDA)含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性显著上升,且均达到差异显著水平(P0.05)。同时发现3个年龄毛竹的净光合速率、蒸腾速率和叶片光合色素含量与注水伐桩数量正相关,而叶片MDA含量及SOD、CAT和POD活性与注水伐桩数量负相关。[结论]模拟干旱环境下,增加注水伐桩可以使1、2和3年生毛竹光合蒸腾能力提高,光合产物积累增加,叶片光合色素含量升高,叶片MDA含量及SOD、CAT和POD活性降低。

Effects of Water Storage in Bamboo Stumps on Physiological Characteristics of Phyllostachys edulis under Simulated Drought Environment

[Objective] dy the water stored in bamboo stump on the physiological characteristics of different aged Phyllostachys edulis (moso bamboo) under drought environment so as to lay a theoretical basis for the management and water-saving irrigation measures in the context of climate change.[Method] 1-year-old, 2-year-old and 3-year-old moso bamboos were selected as the research object. Simulating drought environment by the method of covering film, 9 sample plots with same size in the moso bamboo forest (10 m×20 m) were set up. The plots were trenched and the rhizomes were cut to block moisture transport from the surrounding soil. 3 irrigation treatments were set, i.e. T1 (12 stump with water storage), T2 (18 stump with water storage) and the CK (0 stump with water storage). Each treatment was performed in triplicate to research the physiological responses of bamboo at three age levels with the different water amount stored in the stumps.[Result] The result showed that under simulated drought environment, the net photosynthetic rate (Pn) and transpiration rate (Tr) of 1-year-old, 2-year-old and 3-year-old moso bamboo decreased significantly with the water amount stored in the stumps decreased. The max decline of Pn and Tr in 1-year-old, 2-year-old and 3-year-old moso bamboo reached 74.35% and 73.08%, 59.14% and 36.62%, 60.47% and 61.54%, respectively. The contents of Chlorophyll a (Chl a), Chlorophyll b (Chl b) and Carotenoid (Car) in moso bamboo leaves decreased significantly. The Chl a, Chl b and Car contents of 1-year-old and 3-year-old moso bamboo showed significant differences (P<0.05). The Chl a content of 2-year-old moso bamboo showed significant difference, but there was no significant difference in the content of Chl b and Car (P<0.05). And the Chl a/b in the three aged moso bamboo were not significantly different (P<0.05). The superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity as well as the malondialdehyde (MDA) content in moso bamboo leaves increased significantly (P<0.05). There was a positive relationship between the photosynthesis, the photosynthetic pigment content of moso bamboo and the quantity of moso bamboo stumps, while the MDA content and SOD, CAT and POD activity were negatively related to the quantity of moso bamboo stumps.[Conclusion] This study showed that increased water storage in moso bamboo stumps could significantly improve the photosynthesis of moso bamboo, increase the accumulation of photosynthetic products and leaf photosynthetic pigment content and decrease MDA content and SOD, CAT and POD activity in a drought environment.