【摘要】 为了解氮沉降和生物质炭对毛竹Phyllostachys edulis叶片光合特性的影响,研究了4种氮沉降(0 kg·hm^-2·a^-1,N₀;30 kg·hm^-2·a^-1,N₃₀;60 kg·hm^-2·a^-1,N₆₀;90 kg·hm^-2·a^-1,N₉₀)下施加3种不同强度(0 t·hm^-2,BC₀;20 t·hm^-2,BC₂₀;40 t·hm^-2,BC₄₀)生物质炭处理后2龄毛竹新老叶片光合及叶绿素荧光特性的变化。结果表明:氮沉降和生物质炭均促进了毛竹新老叶的最大净光合速率(P_max),气孔导度（G_s）和蒸腾速率（T_r）,生物质炭同时提高了老叶实际量子产量[Y（Ⅱ）]和PSⅡ潜在活性（F_v/F₀）。与不施加生物质炭相比（BC₀）,N₃₀下施加20 t·hm^-2生物质炭的老叶及N₆₀下施加20 t·hm^-2生物质炭(BC₂₀)的新老叶叶色值显著降低;N₆₀处理下施加生物质炭,毛竹新老叶的最大光化学效率（F_v/F_m）,F_v/F_o和Y（Ⅱ）均提高,而N₉₀处理下施加生物质炭,毛竹新老叶的F_v/F_m和F_v/F_o均降低。由此认为:氮沉降条件下施加生物质炭有利于毛竹新老叶片的光合固碳能力;大气氮沉降背景下,施加生物质炭有利于提高毛竹生产力。更多还原

【Abstract】 To understand the effects of nitrogen（N）deposition and biochar amendments on photosynthesis of new and old leaves of Moso bamboo（Phyllostachys edulis）,effects of four N additions(N₀:0 kg·hm^-2·a^-1,N₃₀:30 kg·hm^-2·a^-1,N₆₀:60 kg·hm^-2·a^-1,and N₉₀:90 kg·hm^-2·a^-1)and three biochar amendments(BC₀:0 t·hm^-2,BC₂₀:20 t·hm^-2,and BC₄₀:40 t·hm^-2)on photosynthesis and chlorophyll fluorescence characteristics of new and old leaves in two-year-old Moso bamboo were determined using LI-6400 portable photosynthesis system,PAM-2500 chlorophyll fluorescence spectrometer and SPAD-502 chlorophyll meter in Moso bamboo plantations（20m×20 m）.Results showed that N deposition and biochar amendment significantly increased（P<0.05）the maximum net photosynthetic rate(P_max),stomatal conductance（G_s）,and transpiration rate（T_r）of new and old leaves.Biochar amendments significantly increased（P<0.001）effective quantum yield of PhotosystemⅡ（PS-Ⅱ）[Y（Ⅱ）]and potential activities of PS-Ⅱ（F_v/F₀）of old leaves.In combination with both N depositions(N₃₀and N₆₀),BC₂₀significantly decreased（P<0.001）the relative chlorophyll content（SPAD）of old leaves compared with the N depositions alone.The SPAD of new leaves for N₆₀-BC₂₀was significantly lower（P<0.001）than N₆₀-BC₀.Also,both biochar amendments in combination with N₆₀significantly increased（P<0.001）maximal potential quantum yield of PS-Ⅱ（F_v/F_m）,F_v/F_o,and Y（Ⅱ）of new and old leaves compared to N depositions alone.However,biochar amendments in combination with N₉₀significantly decreased（P<0.001）both F_v/F_mand F_v/F_oof new and old leaves compared to N depositions alone.In conclusion,this study demonstrated that biochar amendments promoted photosynthesis of leaves and thus increased productivity of a Moso bamboo forest with the background of globally increasing N deposition.更多还原