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【目的】研究干旱条件下伐桩注水对毛竹光合蒸腾特性的影响及其与环境因子间的关系,为毛竹林节水灌溉提供理论参考。【方法】在试验毛竹林中选取10 m×20 m样地9块,设置3个伐桩注水处理CK(0个)、T1(12个)和T2(18个),测定各处理2年生立竹的光合蒸腾生理指标及各主要环境因子。【结果】(1)不同处理下毛竹净光合速率(P_n)与蒸腾速率(T_r)日变化趋势基本相同,均为单峰曲线,均无“光合午休”现象,净光合速率与蒸腾速率日变化均表现为T2>T1>CK。(2)各处理下毛竹水分利用效率(EWUE)均为双峰曲线,随着注水伐桩数量的增加而降低,全天基本表现为CK>T1>T2。(3)不同处理下对毛竹净光合速率起最大直接作用的环境因子不同,CK处理为空气相对湿度(φ),T1和T2处理为光合有效辐射(RPAR);各处理下对毛竹蒸腾速率起最大直接作用的环境因子均为大气CO_2浓度(C_a)。(4)各处理下毛竹净光合速率和蒸腾速率的主要决定变量均为RPAR;T1和T2处理下毛竹净光合速率、蒸腾速率的主要限制变量均分别为空气温度(t_a)、φ,而CK处理分别为φ、C_a。【结论】注水伐桩数量与毛竹净光速率和蒸腾速率正相关,而与水分利用效率负相关。增加注水伐桩能够显著提高毛竹的光合蒸腾能力,增加毛竹光合产物的积累,并且可以改变环境因子对毛竹净光合速率与蒸腾速率的影响作用。
【Objective】 The objective of this study was to investigate the effects of water injection on the photosynthetic and transpiration characteristics of Phyllostachys pubescens under drought conditions and its relationship with environmental factors to provide a theoretical reference for water saving irrigation of Moso bamboo forests. 【Method】 Nine plots of 10 m × 20 m were selected in the experimental bamboo groves. CK (0), T1 (12) and T2 (18) Photosynthetic and Physiological Indexes of Bamboo and Its Main Environmental Factors. 【Result】 (1) The diurnal variation trend of net photosynthetic rate (P_n) and transpiration rate (T_r) of Phyllostachys pubescens Phyllostachys pubescens Phyllostachys pubescens Phyllostachys pubescens Phyllostachys pubescens Phyllostachys pubescens Phyllostachys pubescens Phyllostachys pubescens var. Diurnal changes showed as T2> T1> CK. (2) EWUE under all treatments was a bimodal curve, which decreased with the increase of the number of water logging piles. The whole day showed CK> T1> T2. (3) Under different treatments, the environmental factors that had the greatest direct effect on the net photosynthetic rate of Phyllostachys pubescens were different. CK was air relative humidity (φ), T1 and T2 were photosynthetically active radiation (RPAR) The most direct environmental factors are the atmospheric CO 2 concentration (C_a). (4) The main determinants of net photosynthetic rate and transpiration rate of Phyllostachys pubescens were RPAR. The main limiting variables of net photosynthetic rate and transpiration rate of Phyllostachys pubescens under T1 and T2 treatments were air temperature (t_a), φ, and CK Processes were φ, C_a respectively. 【Conclusion】 There is a positive correlation between the number of water logging and the net photosynthetic rate and transpiration rate, but negatively correlated with water use efficiency. Increasing water logging pile can significantly improve the photosynthetic and transpiration ability of bamboo, increase the accumulation of photosynthate, and can change the environmental factors on the net photosynthetic rate and transpiration rate of bamboo.