中文摘要：

为了解不同竹龄毛竹对于光能的动态响应,以亚热带常绿阔叶林优势树种——毛竹Phyllostachys edulis 3种竹龄（2年生、4年生、6年生）的冠层叶片（2龄）为材料,利用便携式叶绿素荧光仪（PAM-2100）和相对叶绿素含量计（SPAD-502）,研究不同竹龄毛竹冠层叶片光系统Ⅱ（P SⅡ）荧光参数特征。结果表明：3种竹龄毛竹在荧光参数日变化均值（NPQ、qN、ETR）、PSII可逆恢复趋势（F_t、F_o、F_m）和RLC曲线（α、E TRmax、Ik）皆为4年生〉2年生〉6年生,表明在相同环境条件下,4年生毛竹的综合光合性能最优;2年生毛竹冠层叶具有较高的SPAD、Fv/F_o、Fv/F_m,反映其具有较高的潜在光能利用率和耐环境胁迫能力;在6月（大年新竹展叶后期或成竹换叶末期）,2龄竹叶SPAD值有随年龄增加而降低的趋势;相关分析表明,SPAD与Yield、Fv/F_o呈极显著正相关（P〈0.01）,与PAR、ETR、F_t呈极显著负相关（P〈0.01）,与NPQ呈显著负相关（P〈0.05）,表明SPAD值在研究毛竹叶绿素荧光过程中具有重要的参考价值;主成分分析进一步表明,PSⅡ叶绿素荧光参数涵盖了毛竹叶片光适应下的荧光产量和能量耗散、暗适应下的光能利用效率和相对电子传递速率3个主要方面,可以作为研究毛竹光合生理的有效探针。因此,可通过及时择伐6年生毛竹（或III度竹）以上老竹,适当提高4年生毛竹（或Ⅱ度竹）在竹林中的比重;同时,针对笔者所在样地,建议于6月换叶集中末期对竹林追施氮肥以促进后期生长,通过优化毛竹立竹结构和林肥管理来提高毛竹林经营综合效益。

英文摘要：

A study on daily variation and Characteristic of PS Ⅱ chlorophyll fluorescence at canopy layers in leaves of Phyllostachys edulis of three different years old, a dominant bamboo species in subtropical evergreen broadleaved forest of China were conducted. The parameters were measured by portable chlorophyll fluorometer（PAM-2100） and chlorophyll meter（SPAD-502） on a fixed observation tower in Qingshan Mountain Linan, Zhejiang Province. The results showed that Mean daily variation of fluorescence parameters（NPQ, qN, ETR）, PSII reversible recovery ability（F_t, F_o, F_m） and rapid light curve（α, ETRmax, Ik） were in the same order： 4 years old bamboo 〉2 years old bamboo 〉6 years old bamboo, indicated that under the same conditions, 4 years old bamboo had optimum photosynthetic performance followed with 2 years old bamboo and 6 years old bamboo; 2 years old bamboo recorded high value in SPAD, Fv/F_o, Fv/F_m, Reflected its higher potential energy utilization and the ability of resistance to environmental stresses; There was a tendency that leaf SPAD of 2 years old bamboo were decreased with increasing age in rapid growth period; Correlation Analysis showed that the SAPD had high significant positive correlation with Yield and Fv/F_o（P〈0.01）, had high significant negative correlation with PAR, ETR and F_t（P〈0.01）, and also had significant negative correlation with NPQ（P〈0.05）,demonstrated that the SPAD index had important reference value in the process of the research on bamboo chlorophyll fluorescence; Principal Components Analysis further suggested PS Ⅱ chlorophyll fluorescence parameters involving fluorescence Yield and energy dissipation under light adaptation, light use efficiency under dark adaptation and relative electron transfer rates in three main aspects may be used as an effective probe in research of Photosynthetic Physiology.Therefore,from the perspective of intensive management of Phyllostachy edulis,proportion of 4 years old bamboo（or II degree bamboo） s