AMF对玉米生长、根系低分子有机酸分泌与Cd累积的影响.

The ecological functions of arbuscular mycorrhizal fungi (AMF) were explored by investigating its effects on maize growth, mineral nutrition, low-molecular-weight organic acid secretion, and Cd uptake via a root-bag experiment in soil polluted with Cd in the Huize lead-zinc mining area of Yunnan Province. The results showed that AMF promoted maize growth and significantly increased photosynthetic rate, plant height, and biomass. The absorption of N, P, and K increased by 14.2–19.1-fold, and tartaric acid, malic acid, oxalic acid, and succinic acid secretion by roots increased by 1.1–3.8-fold. In addition, AMF resulted in a significant increase of 22.5% in iron- and manganese-oxidized Cd content and a significant decrease of 12.8% in organic-bound Cd content in the maize rhizosphere, but no significant change in exchangeable and available Cd content was observed. AMF significantly reduced maize shoot and root Cd content by 32.7% and 77.9%, respectively, but significantly increased Cd accumulation in maize shoot and root by 12.5-fold and 25.8%, respectively. Correlation analysis showed that shoot Cd accumulation presented extremely significant positive correlations with oxalic acid, tartaric acid, malic acid, and succinic acid secretion, and iron- and manganese-oxidized Cd content. Thus, these results showed that AMF can promote the absorption of nutrients in maize, regulate the secretion of low-molecular-weight organic acid and Cd form in the rhizosphere, and reduce maize Cd content, thereby promoting plant growth. [ABSTRACT FROM AUTHOR]