低pH对AM真菌侵染三叶草根系的影响

Influence of Low pH on the Colonization of Clover Roots by AM Fungi

以白三叶草Trifolium pratense为宿主,接种AM真菌(根内球囊霉Glomus intraradices和珠状巨孢囊霉珠状巨孢囊霉),设置2个土壤pH(5.5和6.5),研究低pH对AM真菌侵染三叶草根系的影响.研究发现,在短暂(12 d)的pH处理后,植株生物量没有受到不同pH处理的影响;但是,不同pH和不同菌种都对AM真菌的根系侵染率、根系碱性磷酸酶(ALP)活性、外生菌丝ALP活性产生显著的影响,菌种和pH之间没有交互作用.低pH对上述3个指标具有抑制效应.根内球囊霉侵染的根系上述3个指标均大于珠状巨孢囊霉侵染的根系,而且珠状巨孢囊霉对低pH更为敏感.试验数据表明,在影响植株的生物量之前,低pH已经对AM真菌的侵染产生显著影响.

The influences of pH （5.5 and 6. 5 ） on mycorrhizal colonization of clover （ Trifolium repens） roots by AM fungi Glomus intrarndices and Gigaspora margarita were investigated. Low pH （5.5） did not affect biomass of host plant. However, low pH treatment resulted in significant reduction in mycorrhizal colonization and alkaline phosphatase （ALP） activities of host roots and AM external hyphae. Furthermore, Gigaspora margarita was more sensitive to low pH and its inoculation leaded to higher decrease in the above three parameters compared with Glomus intrarndices inoculation. The results suggested that low pH affects AM colonization before it affects biomass of host plants.