Lv Haihan, Ji Chenchen, Ding Jingli, Yu Lu, Cai Hongmei
Microelement Research Center, Huazhong Agricultural University, Wuhan 430070, China.
College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
Plants (Basel). 2022 Aug 31;11(17):2271. doi: 10.3390/plants11172271.
Due to global industrialization in recent decades, large areas have been threatened by heavy metal contamination. Research about the impact of excessive Zn on N and P transformation in farmland has received little attention, and its mechanism is still not completely known. In this study, we planted rice in soils with toxic levels of Zn, and analyzed the plant growth and nutrient uptake, the N and P transformation, enzyme activities and microbial communities in rhizosphere soil to reveal the underlying mechanism. Results showed high levels of Zn severely repressed the plant growth and uptake of N and P, but improved the N availability and promoted the conversion of organic P into inorganic forms in rice rhizosphere soil. Moreover, high levels of Zn significantly elevated the activities of hydrolases including urease, protease, acid phosphatase, sucrase and cellulose, and dehydrogenase, as well as the abundances of , , , and , which contributed to the mineralization of organic matter in soil. Additionally, toxic level of Zn repressed the nitrifying process by decreasing the abundance of nitrosifying bacteria and promoted denitrification by increasing the abundance of , which resulted in decreased NO concentration in rice rhizosphere soil under VHZn condition.
近几十年来，由于全球工业化，大片地区受到重金属污染的威胁。关于过量锌对农田氮磷转化影响的研究很少受到关注，其机制仍不完全清楚。在本研究中，我们在锌含量达到毒性水平的土壤中种植水稻，并分析了植株生长和养分吸收、根际土壤中的氮磷转化、酶活性和微生物群落，以揭示其潜在机制。结果表明，高浓度锌严重抑制了植株生长以及氮磷吸收，但提高了水稻根际土壤的氮有效性，并促进了有机磷向无机磷的转化。此外，高浓度锌显著提高了包括脲酶、蛋白酶、酸性磷酸酶、蔗糖酶和纤维素酶以及脱氢酶在内的水解酶活性，以及、、、和的丰度，这有助于土壤中有机物的矿化。此外，锌的毒性水平通过降低亚硝化细菌的丰度抑制硝化过程，并通过增加的丰度促进反硝化作用，导致在高锌条件下水稻根际土壤中NO浓度降低。
