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| Response of microbial community to arsenic contamination in two major type of paddy soils in the middle and lower reaches of the Yangtse River |
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Abstract In a pot experiment, the effects of As contamination, soil type and rice cultivar on the composition of soil microbial communities in rice heading stage were unalyzal using phospholipid fatty acid (PLFA) technique. The results unveiled that the amount of total PLFAs and microbial compositions were to some extent affected by arsenic contamination, soil types and rice cultivars. The As contaminated soils had a higher amount of total PLFAs than the uncontaminated soils. Yellow Paddy soils (YP) had higher total PLFAs, fungi to bacteria ratio (F/B), Gram-negative bacteria to Gram-positive bacteria ratio (G+/G-) and saprotrophic fungi to arbuscular mycorrhizal fungi ratio (SF/AMF) than in Red Paddy soils (RP). Total PLFAs associated with indica plants vs. those associated with japonica and hybrid plants decreased by an average of 30.0% in YP, but increased by 24.8% in RP. Partial Mantel tests and redundancy analysis (RDA) showed that soil pH, DOC, NH4+ and As concentration were the dominant factors in shaping soil microbial communities. The individual PLFAs including 20:0, i17:1ω9c, 18:1ω9c, cy17:0 and 18:3ω6c were easily affected by As contamination. Aggregated boosted tree (ABT) analysis suggested that soil types and rice cultivars exerted more influence than As concentration on the variation of parameters of total PLFAs, F/B, G+/G- and SF/AMF.
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Received: 28 February 2014
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