Chen Fang-Qing, Guo Cheng-Yuan, Wang Chuan-Hua, Xu Wen-Nian, Fan Da-Yong, Xie Zong-Qiang
Center of Ecological and Environmental Science, China Three Gorges University, Yichang 443002, Hubei, China.
Ying Yong Sheng Tai Xue Bao. 2008 Jun;19(6):1229-33.
Salix variegate, a widely distributed species along the riverbank in Three Gorges Reservoir area, plays an important role in soil conservation and riverbank stabilization. Waterlogging from April to May was simulated in 2006 to test the adapting ability and mechanism of S. variegate seedlings to water environment change resulted from the construction of Three Gorges Project. The results showed that under waterlogging, all of the S. variegate seedlings could survive, but their maximum photosynthesis (Pmax), transpiration rate (Tr), water use efficiency (WUE), and stomatal conductance (Gs) decreased significantly with the prolongation of waterlogging. In the early period of waterlogging (20 days), these indices changed little, with the Pmax and Tr decreased by 18.5% and 2.2%, respectively, compared with the control. After 30 days, Pmax and Tr decreased by 53.4% and 23.7%, respectively, and then, kept stable. The contents of chlorophyll and carotenoid and their ratio decreased significantly with the prolongation of waterlogging, while the ratio of chlorophyll a to b increased significantly. The ratio of chlorophyll to carotenoid ranged in 4.873-6.883, and that of chlorophyll a to b ranged in 2.855-3.912. Adventitious roots were developed after waterlogging, which would benefit the oxygen supply for the plants. It was suggested that S. variegate had good adaptability to waterlogging, and could be used as a pioneer species in the restoration of degraded water-level fluctuation zone.
三峡库区河岸广泛分布的变种柳，在土壤保持和河岸稳固方面发挥着重要作用。2006年模拟了4月至5月的涝渍情况，以测试变种柳幼苗对三峡工程建设导致的水环境变化的适应能力和机制。结果表明，在涝渍条件下，所有变种柳幼苗均能存活，但随着涝渍时间延长，其最大光合速率（Pmax）、蒸腾速率（Tr）、水分利用效率（WUE）和气孔导度（Gs）显著下降。在涝渍初期（20天），这些指标变化不大，与对照相比，Pmax和Tr分别下降了18.5%和2.2%。30天后，Pmax和Tr分别下降了53.4%和23.7%，随后保持稳定。随着涝渍时间延长，叶绿素和类胡萝卜素含量及其比值显著下降，而叶绿素a与b的比值显著增加。叶绿素与类胡萝卜素的比值在4.873 - 6.883之间，叶绿素a与b的比值在2.855 - 3.912之间。涝渍后不定根发育，这有利于为植物提供氧气。研究表明，变种柳对涝渍具有良好的适应性，可作为退化消落带恢复的先锋物种。
