Sano S M, Abbott L K, Solaiman M Z, Robson A D
Soil Science and Plant Nutrition, Faculty of Natural and Agricultural Siences, The University of Western Australia, Crawley, Australia.
Mycorrhiza. 2002 Dec;12(6):285-90. doi: 10.1007/s00572-002-0185-6. Epub 2002 Jul 20.
Arbuscular mycorrhizal (AM) fungi differ in their response to soil pH. Thus, change in soil pH may influence the relative abundance of mycorrhizal fungi inside roots. Root colonization by two AM fungi was studied in relation to addition of lime (CaCO3), quantity of inoculum and inoculum placement. Addition of CaCO3 to an acid soil decreased the colonization of roots by Acaulospora laevis but increased colonization by Glomus invermaium when both fungi were present. In acid soil (pH 4.7), almost all roots were colonized by A. laevis, while G. invermaium was dominant when soil pH was increased to pH 7.3. This occurred regardless of whether the inoculum was banded or mixed throughout the soil. There was no effect of CaCO3 on the relative abundance of fungi inside roots at intermediate rates of CaCO3 application (pH 5.3-6.3) when both fungi were inoculated together. In this experiment, both fungi colonized roots at all levels of CaCO3 when inoculated alone, except for A. laevis at the highest level of CaCO3. We conclude that soil pH affects the competitive ability of these two AM fungi during mycorrhiza formation primarily by affecting hyphae growth in soil and thus the relative abundance of hyphae at the root surface and subsequently inside the root.
丛枝菌根（AM）真菌对土壤pH值的反应各不相同。因此，土壤pH值的变化可能会影响根内菌根真菌的相对丰度。研究了两种AM真菌在添加石灰（碳酸钙）、接种量和接种位置方面对根系的侵染情况。当两种真菌都存在时，向酸性土壤中添加碳酸钙会减少光壁无梗囊霉对根系的侵染，但会增加珠状巨孢囊霉的侵染。在酸性土壤（pH 4.7）中，几乎所有根系都被光壁无梗囊霉侵染，而当土壤pH值升至7.3时，珠状巨孢囊霉占主导地位。无论接种物是条施还是全土混合施入，均是如此。当两种真菌一起接种时，在中等碳酸钙施用量（pH 5.3 - 6.3）下，碳酸钙对根内真菌的相对丰度没有影响。在本实验中，当单独接种时，两种真菌在所有碳酸钙水平下都能侵染根系，但光壁无梗囊霉在碳酸钙最高施用量时除外。我们得出结论，土壤pH值主要通过影响土壤中菌丝的生长，进而影响根表面及随后根内菌丝的相对丰度，从而影响这两种AM真菌在菌根形成过程中的竞争能力。
