中科院武漢植物園科研人員對人工植被恢復和自然恢復對三峽庫區(qū)消落區(qū)土壤質(zhì)量的不同影響進行了深入研究，初步探明了不同植被恢復方式對土壤所產(chǎn)生影響的差異,。相關成果發(fā)布在《環(huán)境科學與污染研究》上。
據(jù)了解,，三峽水庫蓄水至175米高度后,，在庫區(qū)兩岸形成高度差達30米的消落區(qū)。受庫區(qū)反自然節(jié)律的水文條件,，以及長達半年之久淹沒的影響,，消落區(qū)原有植被因無法適應現(xiàn)有環(huán)境而死亡，進而使該地出現(xiàn)“裸凸”地帶,。
目前三峽庫區(qū)消落區(qū)自然恢復的植被,，主要以草本植物，尤其是一年生草本植物為主,，而人工植被恢復區(qū)植被則包括草本,、灌木和喬木等。該園系統(tǒng)生態(tài)學科組博士葉琛在研究員張全發(fā)指導下,，通過對三峽庫區(qū)消落區(qū)人工植被恢復區(qū)(包括忠縣,、萬州和秭歸)與自然恢復區(qū)的土壤質(zhì)量進行對比分析，探討了不同植被恢復方式對土壤質(zhì)量的影響機制,。
科研人員發(fā)現(xiàn),，自然恢復區(qū)擁有較高草本植物覆蓋度的土壤,，它的土壤質(zhì)量指數(shù)較高,。這主要因為較高覆蓋度的草本植物能夠提高土壤的有機質(zhì)和氮含量，同時草本植物擁有大量的較細的根系,，根系分泌物能夠提高土壤的理化性質(zhì)，進而提高土壤的質(zhì)量,。該研究結果揭示了三峽庫區(qū)消落區(qū)高蓋度的草本植物具有較高的土壤恢復潛力,。（生物谷 Bioon.com）
生物谷推薦的英文摘要
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.
