摘要
利用LI 6400光合作用系统测定了干旱胁迫和正常灌溉两种处理下,塔里木沙漠公路防护林中乔木状沙拐枣(Calligonum arborescens)净光合速率、蒸腾速率以及水分利用效率等气体交换特性的日变化及季节变化动态。分析得出:两种处理下沙拐枣净光合速率在不同生长季的日变化动态均为单峰型;蒸腾速率除8月干旱胁迫处理下表现出微弱的双峰变化外,其余也为单峰型;干旱胁迫显著降低了沙拐枣的光合能力和蒸腾能力,而且随着干旱胁迫时间的持续,净光合速率和蒸腾速率降低的幅度在不断增加。干旱胁迫所引起的土壤含水量的降低和植物体内的水分亏缺并没有提高沙拐枣的水分利用效率,反而使其有着明显的下降。但尽管如此,沙拐枣在持续干旱的情况下依然能够维持生长,它通过适当降低蒸腾减少水分散失和降低光补偿点以提高弱光利用能力等方法来进行必要的光合积累,这说明沙拐枣有着极强的耐旱能力和适应极端环境的本领,而且通过沙拐枣在长期干旱胁迫处理下的顽强表现,也充分说明沙漠公路防护林在人工管理过程中依然存在着进一步节水的可能性。
Tarim highway is the longest high-grade desert road in the world. Shelterbelt was used to avoid moving sand and blowing wind along the Tarim highway. Calligonum arborescens is one of the important desert species in configuration of the shelterbelt. With the Lio6400 system we measured the diurnal change of net photosynthesis, transpiration and water use efficiency of Calligonum arborescens in different seasons under treatments of drought and irrigation. The following results have been obtained： （1）The diurnal changes of photosynthesis rates of Calligonum arborescens under the two treatments were unimodal curves in different seasons, and that of transpiration rates were unimodal curves except the drought treatment in August. （2）Drought stress could reduce the rates of photosynthesis and transpiration of Calligonum arborescens remarkably, and the influence would enhance with the continuance of drought stress treatment.（3）Because of drought, the soil water content and plant water decreased, but the decrease didn＇t improve the water use efficiency of Calligonum arborescens. Nevertheless, Calligonum arborescens could live and grow in the very drought environment due to elementary accumulation of photosynthetic production through ways of reducing the respiration and the light compensation point, etc. The desert species, Calligonum arborescens, has strong ability to endure drought and adapt the most rigorous environment, which imply the possibility of saving water further in the management of shelterbelt along the desert high way.
出处
《中国沙漠》
CSCD
北大核心
2007年第3期460-465,共6页
Journal of Desert Research
基金
中国科学院知识创新工程重要方向性项目(KZCX3SW34202)
科技部"西部开发科技行动"重大项目(2004BA901A211)共同资助
