塔克拉玛干沙漠南缘3种果树幼苗光合及抗逆性研究

Photosynthetic and Physiological Characteristics of Three Fruit Trees in the Southern Fringe of Taklamakan Desert

于2010年7~8月份,以塔克拉玛干沙漠南缘绿洲-荒漠过渡带人工种植的桑树（Morus albaL.）、沙枣（Elaeagnus angustifoliaL.）和杏树（Prunus armeniacaL.）幼苗为材料,研究了它们在相同生境条件下光合响应特征、水势、脯氨酸和可溶性糖含量等生理指标的变化,并用隶属函数值法对3种果树幼苗的抗旱性进行综合评价。结果表明：（1）3种果树幼苗光响应曲线具有相同的变化规律,当光合有效辐射（PAR）在0~200μmol.m-2.s-1之间变化时,净光合速率（A）随着PAR的增大呈直线增大,当PAR〉200μmol.m-2.s-1时,A随PAR的变化呈二次曲线变化;（2）3种果树幼苗的光响应参数最大光合速率（Amax）、曲角（K）、表观量子效率（φ）、暗呼吸速率（Rday）、光饱和点（LSP）、光补偿点（LCP）以及光合色素的变化趋势并不完全一致,其中桑树具有最大的Amax、φ、Rday和叶绿素含量,而杏树的LSP最高,LCP最低,因此桑树具有最大的光能利用效率,而杏树能更有效地利用强光进行光合作用;（3）3种果树幼苗脯氨酸（Pro）、可溶性糖以及丙二醛（MDA）含量,除沙枣和杏树之间可溶性糖含量差异不显著外,其他指标含量差异在3种果树之间均达到显著水平（P〈0.05）;（4）在本研究期间3种果树的抗逆性表现为沙枣〉桑树〉杏树。研究发现,塔克拉玛干沙漠南缘绿洲-荒漠过渡带的3种果树幼苗光响应曲线变化趋势基本一致,体现了植物对环境条件适应的一致性,但是各个生理指标的变化趋势并不完全一致,这可能是由于植物种对环境条件的适应差异所导致。

Photosynthesis,the water potential,the contents of proline and soluble sugar and other physiological index of Morus alba L.,Elaeagnus angustifolia L.and Prunus armeniaca L.in the southern fringe of Taklamakan Desert were determined in the same condition during July and August in 2010.We also comprehensively evaluated the drought resistance of three seedlings of fruit trees by means of membership function.The results are as follows：（1）The seedlings of the three fruit trees showed similar light response curves under the photosynthetic active radiation（PAR） of 0～200 μmol·m-2·s-1,the net photosynthetic rate（A） increased linearly with increasing PAR and when PAR200 μmol·m-2·s-1,A showed a quadratic change with the PAR;（2）The parameters of photosynthesis Amax,K,φ,Rday,LSP,LCP and photosynthetic pigments were incomplete accord of the seedlings of three fruit trees,Morus alba L.had highest Amax,φ,Rday values and chlorophyll content,while the P.armeniaca L.had the highest LSP and lowest LCP.Therefore,M.alba L.had the largest light use efficiency,and P.armeniaca L.could use efficiently the glare light for photosynthesis;（3）The contents of Pro,MDA and soluble sugar of three seedlings of fruit trees were analyzed,we found that all physiological indexes of fruit trees except the content of soluble sugar between E.angustifolia L.and P.armeniaca L.were significantly different（P0.05）;（4）The stress resistance of three tree seedlings in proper order was E.angustifolia L.M.alba L.P.armeniaca L..The research suggested that the light response curve of 3 fruit trees seedlings at the desert-oasis ecotone in the south fringe of Takelamkan desert were complete accord,which reflects the same response of different plants to environmental conditions,while the disaccord trend of physiological characteristics indicated the different adaption to the same environmental condition among different plants.