基于光合--光响应特性的柳树优良无性系光能利用效率的评价

Evaluation of radiation use efficiency of superior clones of Salix based on photosynthetic light-response characteristics

利用直角双曲线修正模型对51种柳树优良无性系的光合-光响应曲线进行拟合,分析其光合-光响应特征参数。结果表明:当光照强度开始增加时,各无性系间差异较小,但随着光强增加,各无性系净光合速率达到最高点后呈非线性缓慢减小,其中柳Q43、柳Q31和柳SH48的净光合速率明显高于其他品种。51种柳树优良无性系中柳Q43的最大净光合速率最高,为32.50μmol/(m2·s),绵毛柳的最大净光合速率最低,仅为11.74μmol/(m2·s);柳2462的暗呼吸速率较小,仅为0.43μmol/(m2·s),垂柳109的暗呼吸速率要高于其8倍;柳84和柳2642光补偿点较低,为7.47和8.70μmol/(m2·s);加拿大柳的光饱和点最高,为1 996.48μmol/(m2·s)。采用主成分分析法将这4个光合-光响应特征参数综合为2个主成分,其累计贡献率可达81.494%。根据2个主成分的值将51种柳树无性系分为4类,并利用4类柳树株高和基径的年生长量对主成分分析的分类结果进行验证,认为第Ⅰ类柳树对光的利用范围最广,对环境适应能力最强,具有较高的光能利用效率,年生长量最大,为优良的高光效品种。

We determined the photosynthetic light-response curves of 51 clones of Salix using modified rectangular hyperbola model in order to analyze their characteristic parameters of photosynthetic lightresponse. The results showed that at the beginning of light increase,there were no distinct differences in the photosynthetic rate among the clones; as the light intensity continued to increase, the net photosynthetic rate（ Pn） of each clone peaked and then declined nonlinearly, of which, net photosynthetic rates of clones Q43,Q31 and SH48 were apparently higher than those of other clones or species. The maximum net photosynthetic rate（ Pnmax） of Q43 was the highest（ 32. 50 μmol/（ m2·s））among 51 superior clones,and that of S. erioclada the lowest,11. 74 μmol /（ m2·s）. The dark respiration rate（ Rd） of the clone 2462 was the lowest（ 0. 43 μmol/（ m2·s））,while that of S.babylonica was 9 times higher. Light compensation points（ LCP） of clones 84 and 2462 were low,which were 7. 47 and 8. 70 μmol /（ m2·s）,and light saturation point（ LSP） of Salix sp. was the highest（ 1 996. 48 μmol/（ m2·s））. The principle component analysis suggests that the four indexes could be summarized as two principle components,contributing 81. 494%. The 51 clones were divided into four types according to the principle component analysis,and the result was verified by measuring annual growth of height and branch diameter of the four types of Salix. It is suggested that the superior clones in type Ⅰ,with a wide range of use of light,have the strongest adaptation ability to environment,higher radiation use efficiency and the biggest annual growth,and thus were elite high light-efficiency ones.