Yang Chang-Ming, Cai Wen-Juan, Li Jian-Hua
State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
Ying Yong Sheng Tai Xue Bao. 2012 Apr;23(4):1083-9.
A simulation test was conducted to study the effects of saltwater incursion on the microbiological characteristics and denitrification in the riparian rhizosphere soils vegetated with different plants in Chongming Island of Shanghai. Saltwater incursion changed the microflora in the rhizospheric soils. Except for actinomycete whose quantity had slight increase, the quantities of bacteria, fungi, nitrifiers, and denitrifiers all decreased to some extent by saltwater incursion, with the denitrifiers decreased by 51.8%, suggesting that the riparian soil microflora responded differentially to saltwater incursion. The activities of soil nitrogen-transforming enzymes were significantly inhibited by saltwater incursion, and the inhibitory effects differed with the enzymes. Nitrite reductase activity was most sensitive to saltwater incursion, with an inhibition rate of 43.5%, followed by urease activity, with 37.4% inhibition, and by dehydrogenase (29.5% inhibition). Saltwater incursion inhibited the denitrification, with the average denitrification rate decreased by 34.9%. There existed significant differences in the eco-physiological responses of the microbes in the rhizosphere soils vegetated with different plants to the saltwater incursion. The microbial quantities and enzyme activities showed the highest inhibition percentages in the rhizosphere soil of Zizania aquatica, followed by in the rhizosphere soils of Acorus calamus and Phragmites australis. Under saltwater incursion, the inhibition percentages of microbial quantities, enzyme activities, and denitrification rate in the rhizosphere soil of A. calamus-P. australis were significantly lower, as compared with those in the rhizosphere soils vegetated with Z. aquatica, A. calamus, and P. australis, respectively, suggesting that mixed vegetation showed a better buffer effect on the responses of riparian rhizosphere soil microbiological processes and denitrification to saltwater incursion.
开展了一项模拟试验，以研究咸水入侵对上海崇明岛不同植物植被河岸根际土壤微生物特征及反硝化作用的影响。咸水入侵改变了根际土壤中的微生物群落。除放线菌数量略有增加外，细菌、真菌、硝化菌和反硝化菌的数量均因咸水入侵而有所下降，其中反硝化菌下降了51.8%，这表明河岸土壤微生物群落对咸水入侵的响应存在差异。咸水入侵显著抑制了土壤氮转化酶的活性，且不同酶的抑制效果不同。亚硝酸还原酶活性对咸水入侵最为敏感，抑制率为43.5%，其次是脲酶活性，抑制率为37.4%，脱氢酶活性抑制率为29.5%。咸水入侵抑制了反硝化作用，平均反硝化率下降了34.9%。不同植物植被的根际土壤微生物对咸水入侵的生态生理响应存在显著差异。微生物数量和酶活性在菰根际土壤中的抑制率最高，其次是菖蒲和芦苇根际土壤。在咸水入侵条件下，菖蒲 - 芦苇根际土壤中微生物数量、酶活性和反硝化率的抑制率分别显著低于菰、菖蒲和芦苇根际土壤，这表明混合植被对河岸根际土壤微生物过程和反硝化作用对咸水入侵响应具有更好的缓冲作用。
