Abstract: The experiment of different photosynthetic active radiation (PAR) was conducted to study the photosynthetic physiological characters of Vetiveria zizanioides and Paspalum orbiculare, and the differences in photosynthesis rate (Pn), transpiration rate (Tr), water use efficiency (WUE) and stomatal conductance (Gs) were also evaluated. The results showed as follows:all the Pn, Tr and Gs increased with the enhanced PAR intensity, and the Pn, Tr and Gs of Paspalum orbiculare were significantly higher than those of Vetiveria zizanioides. But WUE of Vetiveria zizanioides was higher than WUE of Paspalum orbiculare,it indicating that Vetiveria zizanioides is dominant species and Paspalum orbiculare is merely auxiliary species.

Key words: Vetiveria zizanioides, Paspalum orbiculare, photosynthetic physiological character, photosynthetic active radiation

摘要： 在人工控制有效光合辐射增强的条件下,测量了香根草与其伴生种圆果雀稗的光合特性,对比分析两者的光合速率、蒸腾速率、水分利用率和气孔导度对有效光合辐射增强的响应。结果表明,伴生种圆果雀稗的光合能力、蒸腾能力等光合特性都比香根草的强,两者的光合速率、蒸腾速率和气孔导度差异极显著(P<0.01),而圆果雀稗的水分利用率却低于香根草,表明香根草可能因在水分利用中占据优势而成为优势种,圆果雀稗仅为伴生种。

关键词: 香根草, 圆果雀稗, 光合特性, 有效光合辐射