春季毛竹光化学效率空间异质性比较

Comparison of spatial heterogeneity in photochemical efficiency of Phyllostachys pubescens in spring

利用PAM-2100叶绿素荧光测定仪和SPAD 502型相对叶绿素含量测定仪测定不同竹龄(Ⅰ、Ⅱ、Ⅲ度)毛竹上、中、下3冠层相对叶绿素含量(SPAD值)和叶绿素荧光参数变化。结果表明,不同竹龄毛竹上层的光系统Ⅱ(PSⅡ)实际光化学量子效率(Yield)、PSⅡ最大光化学效率(F v/F m)、PSⅡ潜在活性(F v/F o)均显著低于中下层,非光化学荧光淬灭值(NPQ)则显著高于中下层。毛竹上层的SPAD值显著低于中下层,且随着竹龄增长有积累的趋势。综合比较,Ⅲ度毛竹Yield最高;Ⅱ度毛竹具有较好的光响应能力;在高光环境下,毛竹能增加热耗散,从而降低光抑制的程度。

The changes of relative chlorophyll content and chlorophyll fluorescence parameters in top, middle and bottom canopy of different ages＇ PhyUostachys pubescens （ I , II and III degree） were measured by SPAD 502 determinator for relative chlorophyll content and PAM-2100 determinator for chlorophyll fluorescence. The results showed that PS lI actual photochemistry quantum efficiency （Yield）, the PS II highest photochemistry efficiency （Fv/Fm） and PS II lateral reactivity （Fv/Fn） of top canopy in different ages of P. pubescens were significantly lower than the ones of middle and bottom canopy, while non-phyllostachys fluorescence quenching values （NPQ） was significantly higher than the one of middle and bottom canopy. Moreover, top canopy of P. pubescens had significantly lower chlorophyll content than middle and bottom canopy, which was on the trend of accumulation with the growth of the age. After comprehensive comparison, it was discovered that III degree P. pubeseens had the highest value Yield and II degree P. pubescens had good photo response ability. What is more, under high-light environment, P. pubescens could increase heat dissipation so that the degree of photo inhibition was decreased.