中科院武汉植物园科研人员对人工植被恢复和自然恢复对三峡库区消落区土壤质量的不同影响进行了深入研究，初步探明了不同植被恢复方式对土壤所产生影响的差异。相关成果发布在《环境科学与污染研究》上。
据了解，三峡水库蓄水至175米高度后，在库区两岸形成高度差达30米的消落区。受库区反自然节律的水文条件，以及长达半年之久淹没的影响，消落区原有植被因无法适应现有环境而死亡，进而使该地出现“裸凸”地带。
目前三峡库区消落区自然恢复的植被，主要以草本植物，尤其是一年生草本植物为主，而人工植被恢复区植被则包括草本、灌木和乔木等。该园系统生态学科组博士叶琛在研究员张全发指导下，通过对三峡库区消落区人工植被恢复区(包括忠县、万州和秭归)与自然恢复区的土壤质量进行对比分析，探讨了不同植被恢复方式对土壤质量的影响机制。
科研人员发现，自然恢复区拥有较高草本植物覆盖度的土壤，它的土壤质量指数较高。这主要因为较高覆盖度的草本植物能够提高土壤的有机质和氮含量，同时草本植物拥有大量的较细的根系，根系分泌物能够提高土壤的理化性质，进而提高土壤的质量。该研究结果揭示了三峡库区消落区高盖度的草本植物具有较高的土壤恢复潜力。（生物谷 Bioon.com）
生物谷推荐的英文摘要
Environmental Science and Pollution Research
DOI 10.1007/s11356-012-1395-x
The response of mulberry trees after seedling hardening to summer drought in the hydro-fluctuation belt of Three Gorges Reservoir Areas
Xiaohui Huang, Yun Liu, Jiaxing Li, Xingzheng Xiong, Yang Chen, Xiaohua Yin, Dalan Feng
Interest has developed in the potential of mulberry (Morus alba), a woody perennial, for revegetating the hydro-fluctuation belt of the Three Gorges Reservoir due to its resistance to water-logging stress. To be useful, the trees must also be able to withstand dry conditions in summer when temperatures can be very high and droughts become severe quickly. Here, we report a study in which mulberry seedlings were grown in a greenhouse under a variety of simulated soil water conditions reflecting potential summer scenarios in the hydro-fluctuation belt of the Three Gorges Reservoir Area. We compared the responses of two pretreatment groups of mulberry seedlings to different levels of drought stress. The pretreatment groups differed with respect to drought hardening: the daily-managed (DM) group had relative soil moisture held constant in the range 70–80 %, while the drought-hardened (DH) group had relative soil moisture held constant at 40–50 %. Following the month-long pretreatment of seedlings, the two groups of young trees (DM and DH) were then respectively subjected to three levels of drought stress for a month: normal watering, moderate drought stress, and severe drought stress. A series of measurements comparing the physiological status of the plants in the two groups were then made, and the following results were obtained: (1) As drought stress increased, the heights, base diameters, root surface areas, photosynthetic rates (Pn), stomatal conductances (Gs), and transpiration rates (Tr) of the mulberry trees in both groups (DM and DH) decreased significantly, while the specific root area and abscisic acid (ABA) contents had increasing trends. Root activity and instantaneous water use efficiency of mulberry trees in both groups (DM and DH) were all raised under drought stress conditions than under normal watering, but the root/shoot ratio and leaf water potential were lowered. (2) At the same level of soil water content, the heights, base diameters, root/shoot ratios, root surface areas, specific root areas, photosynthetic rates (Pn), stomatal conductances (Gs), and transpiration rates (Tr) of the young mulberry trees in the DH were all significantly higher than those of the control group (DM). Leaf water potential, instantaneous water use efficiency, and abscisic acid content of DH were all significantly lower than DM. Under different degrees of drought stress, the growth of mulberry trees will be inhibited, but the trees can respond to the stress by increasing the root absorptive area and enhancing capacity for water retention. Mulberry trees demonstrate strong resistance to drought stress, and furthermore drought resistance can be improved by drought hardening during the seedling stage.
