水保所知识产出(1956---)知识库

【 目的】磷极易被土壤吸附和固定，导致土壤中磷有效性较低。研究接种丛枝菌根真菌 (arbuscular
mycorrhizal fungi, AMF) 和低磷处理两者交互对紫花苜蓿生长和磷吸收的影响，为提高碱性土壤中磷肥利用率提
供理论依据。【 方法】以黄绵土和紫花苜蓿 (Medicago sativa) 为试验材料进行盆栽试验。在施磷 0、5、20
mg/kg (P0、P5、P20) 3 个水平下，分别设接种和不接种丛枝菌根 Glomus mosseae BGC YN02 (+AMF、–AMF) 处
理。植物生长 120 天后测定植株生物量、磷吸收量、AMF 侵染率以及根际和非根际土壤的 pH、土壤碱性磷酸
酶活性、土壤有效磷含量、土壤微生物生物量磷，分析根际有机酸的组成与含量。【 结果】+AMF 处理中植物
根系被 AMF 侵染，且施磷水平对侵染率没有显著影响；施磷和+AMF 处理显著提高了植株地上部、地下部生
物量以及磷含量，其中 P20+AMF 处理生物量和磷含量最高；根际有机酸总量随施磷水平上升而显著降低，
但+AMF 处理有机酸总量高于–AMF 处理，其中柠檬酸和乙酸含量的变化较为明显；施磷和+AMF 显著降低土
壤碱性磷酸酶活性，增加土壤有效磷含量和微生物生物量磷，且低磷环境 (P0、P5) 下根际土壤碱性磷酸酶活性
和微生物生物量磷均显著高于非根际土；P20 处理显著降低磷利用效率和磷肥利用率，+AMF 处理显著提高磷
肥利用率。【 结论】碱性土壤 (黄绵土) 中，AMF 和紫花苜蓿根系能建立较好的共生关系，低施磷水平 (施磷
量 ≤ 20 mg/kg) 对 AMF 侵染率没有显著影响。施磷和接种 AMF 均可以显著促进紫花苜蓿生长和磷吸收。低磷
环境下，接种 AMF 可以扩大植物根系吸收范围，同时增强根际土壤碱性磷酸酶活性，促进根系分泌有机酸，
特别是乙酸和柠檬酸，从而提高磷肥利用率。

【Objectives】Phosphorus (P) is easily adsorbed and fixed by soil, resulting in low P availability in
soil. This research investigated the interactive effects of AMF and low levels of P fertilizer on alfalfa growth and
P-uptake to identify optimal methods for increasing P efficiency in alkaline soil.【Methods】A pot experiment
was conducted using loessial soil and alfalfa (Medicago sativa) as test materials. The soil was treated with
different P levels (0, 5 and 20 mg/kg, code as P0, P5, P20), and with AMF inoculation (20 g/L Glomus mosseae
BGC YN02; +AMF) or without (–AMF). After 120 days of plant growth, the growth indices of alfalfa, P
concentrations in alfalfa tissues, pH values, alkaline phosphatase activities, available P contents, and microbialbiomass P in the rhizosphere and non-rhizosphere soil were analyzed. The composition and concentration of
rhizosphere organic acids were also measured.【Results】In +AMF treatments, alfalfa roots were colonized by
mycorrhiza, but P application rate had no significant effect on AMF root colonization. Both P application and
AMF colonization significantly increased the dry mass and P concentrations of shoots and roots. The plant dry
mass and P concentration in P20+AMF treatment were significantly higher than in the other treatments. The total
amount of rhizosphere organic acids, especially citrate and acetate, in +AMF treatments decreased with increase in
P application rate, but they were still significantly higher than those in −AMF treatments. Phosphorus and AMF
application significantly decreased soil alkaline phosphatase activity, but increased soil available-P and microbial
biomass P contents. Alkaline phosphatase activity and microbial biomass P in rhizosphere were significantly
higher than in non-rhizosphere. P20 trentment significantly decreased P-uptake efficiency and P-utilization
efficiency, and +AMF significantly increased P-uptake efficiency.【Conclusions】AMF has a good symbiotic
relationship with alfalfa roots in alkaline loessial soil. Low level of P application (≤ 20 mg/kg) has no significant
effect on AMF root colonization. Both P application and AMF colonization could significantly stimulate the
growth and P uptake of alfalfa. In low available P soil, inoculating AMF could broaden absorption area of root,
increase alkaline phosphatase activity in rhizosphere and secretion of organic acids (especially citrate and acetate),
and increase P-uptake efficiency.