毛乌素沙地几种主要植物的光合特性

Photosynthetic Characteristics of Some Plant Species in the Mu Us Desert

利用Li-6400型便携式光合作用系统测定了毛乌素沙地两种主要人工栽培树种(小叶杨和紫穗槐)和4种乡土树种(沙柳、长柄扁桃、蒙古扁桃和榆叶梅)的光响应曲线和CO_2响应曲线,并对2种响应曲线用非直角双曲线模型拟合。结果表明:小叶杨、1 a生沙柳、紫穗槐和榆叶梅对光能的利用效率高于4 a生沙柳、长柄扁桃和蒙古扁桃;小叶杨、沙柳、紫穗槐、长柄扁桃、榆叶梅和蒙古扁桃均为阳生植物;LCP和R_(day),P_(max)和LSP,P_(max)和Φ显著相关;在相同的CO_2浓度下,蒙古扁桃光合作用效率最低,4 a生沙柳、小叶杨、长柄扁桃、榆叶梅、1 a生沙柳和紫穗槐的光合作用效率较高。平茬可有效提高沙柳对光照的利用效率,生物量积累也较快。根据本研究,小叶杨可能为C_4植物,其余6种可能为C_3植物,但仍需进一步的研究才能确定。

The light response curves and carbon dioxide curves of two cultivated species （Populus simon and Amorpha fruticosa ） and four local species （Salix psammophila, Prunus pedunculat, Prunus mongolica and Prunus triloba） in the Mu Us sandy land were measured with LiCor-6400. The results of non-rectan- gle hyperbola fitting indicated that the light efficiency of P. simon,one-year S. psammophila, A. fruticosa and P. triloba were greater than four-year S. psammophila, P. pedunculat and P. mongolica, P. simon, S. psammophila, A. fruticosa, P. triloba, P. peduncular and P. mongolica were heliophyte. Significantly positive correlations were found between LCP and Rday, Pmax and LSP, and P and Ф The photosynthesis efficieneies of four-year S. psammophila, P. simon, P. pedunculat, P. triloba and one-year S. psammophila were higher than that of P. mongolica under the same CO2 concentration. Light use efficiency and biomass of S. psammophila significantly increased because of stumping. According to this study P. simon may be C4 plant, other six plants may C3 plant, however, further studies are needed to prove the conclusion.