不同竹龄青皮竹光合作用与荧光特性的比较

对不同竹龄青皮竹的光合与荧光特征研究表明:不同竹龄的青皮竹净光合速率(P_n)差异显著,1龄竹的净光合速率大于8 μmol·m^-2·s^-1,明显高于3龄竹,说明随着竹龄增加,青皮竹光合固碳能力有所下降。气孔导度(Cond) 、胞间CO₂浓度(C_i)、蒸腾速率(T_r)3个性状都表现为1龄竹>2龄竹>3龄竹。水分利用效率(WUE)表现相反,为3龄竹>2龄竹>1龄竹。光响应曲线表明,当光强始增强时,各竹龄间差异较小,但随着光强的继续增加,不同竹龄出现很大的差异,其中,1龄竹光补偿点和光饱和点相对较高,其潜在净光合速率也高于其它竹龄的青皮竹。青皮竹最大荧光效率(F_v/F_m)平均为0.590 5,光系统Ⅱ活性(F_v/F_o )平均为1.442 0,各叶绿素荧光参数都随着年龄增加而降低,但差异不显著。

A Comparative Study on Photosynthetic and Fluorescence Characteristicsamong Different Aged Bambusa textilis

A study on the photosynthetic and fluorescence characteristics of Bambusa textilis was conducted. The results showed significant differences in net photosynthetic rate(P_n)among different aged Bambusa textilis. The net photosynthetic rate of 1 age bamboos exceeded8 μmol·m^-2·s^-1, much higher than that of 3 age ones, which indicated a decreasing trend of photosynthetic carbon sequestration capacity of B. textilis with its age increased. All of the 3 characters of stomatic conductance(Cond), CO₂ intercellular concentration(C_i)and transpiration rate(T_r)showed a same trend of 1 age bamboo > 2 age bamboo > 3 age bamboo. Contrarily, water use efficiency(WUE)showed an opposite rule of 3 age bamboo> 2 age bamboo > 1 age bamboo. And for light response curve, the differences among various aged bamboos were small at the initial stage of light increase, but apparent differences among them were observed with further light increase. It was relatively higher for 1 age bamboo on its light compensation point and light saturation point, same as its potential net photosynthetic rate(P_max). The average maximum fluorescence efficiency (F_v/F_m) and activity of photosystemⅡ(F_v/F_o)of B. textilis were 0.590 5 and 1.442 0, respectively, and the fluorescence parameters tended to decrease with increasing age, but having not significant difference.