绿洲-沙漠过渡带引种植物光合生理特征研究

为了研究引种植物在绿洲-沙漠过渡带极端干旱条件下的适应性,在自然条件下对3种引种植物文冠果、酸枣、紫叶小檗的光合、水分等生理指标进行了研究。结果表明,1) 3种植物的光响应曲线变化趋势基本一致,均表现为随着光合有效辐射(PAR)的增大净光合速率(P_n)先增大后减小;文冠果和紫叶小檗的光饱和点明显高于酸枣(P<0.01),说明文冠果和紫叶小檗利用强光的能力较大,对光环境的适应性较强;紫叶小檗的最大净光合速率(P_nmax)和暗呼吸速率(R_d)也明显高于文冠果和酸枣,表明紫叶小檗具有高光合耐胁迫的优势。2)3种植物的叶绿素含量和丙二醛含量的变化一致,文冠果均显著高于其他2种植物(P<0.05);3种植物的可溶性糖含量差异不显著(P＞0.05),而紫叶小檗的脯氨酸含量显著高于其他2种植物(P<0.01),说明在该生境下紫叶小檗能够较好的保持体内水分含量,较好的适应该生境。3) 3种植物的清晨水势和正午水势都有相同的大小关系,都是文冠果较大,酸枣最小,而且植物种之间差异极显著(P<0.01),说明紫叶小檗和酸枣的吸水能力较强,它们主要依靠夜间水分恢复能力来应对干旱环境。总的来说,3种植物的光合参数及生理指标的变化趋势不是完全一致,这可能是由于植物种之间的个体差异,以及不同植物对同一生境的差异所致,因此,要想选取适合在策勒绿洲-沙漠过渡带大面积种植的引种植物,还需做进一步的研究。

Photosynthetic and physiological characteristics of introduced plants at the desert-oasis ecotone

To explore adaptability of adventitious plants to extreme arid regions, we studied the photosynthesis characteristics and water potential of three plant species (Xanthoceras sorbifolia, Ziziphus jujuba and Berberis thunbergii) in the natural conditions of the desert-oasis transitional area of the Cele oasis on the southern fringe of the Taklamakan Desert.1) The three plant species showed similar light response curves: the net photosynthetic rate (P_n) increased initially but then decreased. The light saturation point (LSP) of X. sorbifolia and B. thunbergii were significantly higher than that of Z. jujuba (P<0.01), while the P_nmax and R_d of B. thunbergii were both higher than those of X. sorbifolia and Z. jujuba. These results indicated that X. sorbifolia and B. thunbergii can use glare light efficiently for photosynthesis, and B. thunbergii has the advantages of higher photosynthetic efficiency and stronger ability to withstand stress. 2) The content of chl and MDA of X. sorbifolia were significantly higher than those of the other two species (P<0.05), but the soluble sugar contents of the three species were not significantly different (P＞0.05). The Pro content of B. thunbergii was significantly higher than that of the other two species (P<0.01). 3) The X. sorbifolia had the highest water potential in three plants (P<0.01), so B. thunbergii and Z. jujuba have stronger water uptake ability. In summary, the trend of photosynthetic parameters and physiological indicators are not in complete accord; this may be due to individual differences between the species, so in order to select the most suitable adventitious plants in the oasis-desert transitional zone, further research is needed.