VA菌根真菌对石灰性土壤不同形态磷酸盐有效性的影响

用32P示踪法研究了VA菌根真菌对石灰性土壤不同形态磷酸盐有效性的影响。结果表明，VA菌很真菌显著增加了玉米吸收肥料和土壤的磷量。菌根植物和非菌根植物都可不同程度地吸收利用土壤中的Ca2-P、Ca8-P、Fe-P和Al-P，VA菌根真菌增加了玉米对它们的吸收。试验结果还表明，施Ca10-P时接种VA菌很真菌对玉米生长的促进作用比施用其它磷酸盐明显，但Ca10-P不能直接被玉米植株所利用。说明VA菌根真菌能提高土壤中的有效性磷（Ca2-P和Al-P）和缓效性磷（Ca8-P和Fe-P）的有效性。

INFLUENCE OF VA MYCORRHIZAL FUNGI ON AVAILABILITY OF DIFFERENT PHOSPHATES IN CALCAREOUS SOIL

Five synthetic phosphates: dicalcium phosphate. octocalcium phosphate, apatite. Iron phosphate and aluminium phosphate were applied to calcareous soil to simulate Ca₂-P,Ca₈-P, Ca₁₀-P. Fe-P and Al-P type phosphates in the calcareous soill. ³²P was also used in testing the influence of VA mycorrhizal fungi on P uptake of corn plant from these Synthetic phosphates, fertilizer labelled with ³²P and soil phosphorus pool. Results showed that P uptake by corn plant from soil and ³²P-labelled fertjlizer was significantly increased by inoculating Glomus mosseae. Except apatite, all other four synthetic phosphates could be used by both mycorrhizal and non-mycorrhizal corn plant, however VA mycorrhizal fungi infection increased the absorbtion. Although the highest benefit of inoculating VA mycorrhizal fungi was obtained under condition of applying apatite, neither mycorrhizal nor non-mycorrhizl plant could used P in apatite.It is concluded that both mycorrhizal and non-mycorrhizal plant absorbing P from the same sources or phosphate forms-available P and slow- exchangable P in the calcareous soil. inoculating VA mycorrhizal fungi can increase their bioavailability.