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| Effects of EDTA on soil quality and microorganisms in rhizosphere of Cynodon dactylon under lead stress |
| Received:November 07, 2022 Revised:December 01, 2022 |
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| KeyWord:Cynodon dactylon;EDTA;lead;high-throughput sequencing |
| Author Name | Affiliation | E-mail | | JIANG Ranran | School of Agriculture and Life Sciences, Kunming University, Kunming 650214, China | | | JIANG Runhai | School of Agriculture and Life Sciences, Kunming University, Kunming 650214, China | | | ZHU Chengqiang | School of Agriculture and Life Sciences, Kunming University, Kunming 650214, China | | | HOU Xiuli | School of Agriculture and Life Sciences, Kunming University, Kunming 650214, China | hxlyn@aliyun.com |
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| Abstract: |
| To study the effects of the chelating agent ethylenediamine tetraacetic acid（EDTA）on the physicochemical properties, soil enzymes, and microbial community structure in rhizosphere soil of Cynodon dactylon, different concentrations of EDTA[0（CK）, 2.5, 5.0, 7.5, 10.0 mmol·L-1] were applied on lead-contaminated soil, in which the tolerant plant Cynodon dactylon was planted in a pot experiment. The results were as follows：When 2.5 mmol·L-1 EDTA was applied to the rhizosphere soil of Cynodon dactylon, the lowest soil pH was 6.80, and the activities of soil available phosphorus（AP）, soil acid phosphatase, and invertase were the highest, and they were 2.24, 1.57 times, and 1.41 times that of those of the CK, respectively; When 7.5 mmol·L-1 EDTA was applied, the content of available potassium（AK）, ammonium nitrogen, and nitrate nitrogen in rhizosphere soil was the highest, and their values（96.22, 262.00 mg·kg-1, and 15.90 mg·kg-1） were 1.09, 1.30 times, and 6.41 times that of those of the CK, respectively. The diversity of soil microorganisms in the rhizosphere soil of Cynodon dactylon and the number of OTU in the EDTA concentration of 7.5 mmol · L-1 were the highest. Chloroflexi, Acidibacter, Pedomicrobium, and Aspergillus, with the highest relative abundance, increased by 7, 3, 10, 8 percentage points over the CK, respectively. After applying EDTA, the highest relative abundance of Bacillus in the rhizosphere soil of Cynodon dactylon increased by 9 percentage points over the CK; The highest relative abundance of Cladosporium was 4.05 times that of the CK. The activities of soil acid phosphatase, urease, sucrase, and AP positively correlated with Aspergillus and Gibellulopsis, whereas soil urease positively correlated with heavy metalresistant bacteria（Bacillus and Chaetomium）, indicating that heavy metal-resistant microorganisms contributed to the increased content of available nitrogen and phosphorus in the soil. In lead-contaminated soil, the application of appropriate concentration of EDTA can increase the acid phosphatase, invertase activities of plant rhizosphere soil, and diversity and abundance of microorganisms; improves the microecological environment of rhizosphere soil; then improves the remediation effect of tolerant plants on heavy metals. |
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