北京地区大葱和玉米根际VA菌根的季节变化及其与环境因子之间的关系

1986-1987年连续两年系统调查了北京地区大葱(Allium fistulosum L.)和玉米(Zeamays L.)根际 VA 菌根侵染百分率及菌根真菌孢子密度的季节变化。分析了菌根和菌根真菌的发生与几种土壤因子(土壤硝态氮、铵态氮、速效磷和有机质含量,土壤 pH 值)和气候因子(气温、积温、土温、光照、降水量,相对湿度等)之间的关系。结果表明:大葱和玉米的侵染百分率随作物生育期的增长而增加,并以6月和9月的增长速度最快。一年中,植物根际菌根真菌的孢子密度有二个高峰,分别在6-7月和10月。在北京的同一地区,一年中,几种测定的土壤因子变化很小,因此,认为气候因子对菌根发生的季节变化具有更大的影响。用线性相关和关联度分析的结果表明:一年中,菌根的发生与积温的关系最为密切。

SEASONAL VARIATIONS OF VA MYCORRHIZAE IN THE RHIZOSPHERES OF WELSH ONION(ALLIUM FISTULOSUM)AND CORN(ZEA MAYS)IN BEIJING AND THEIR RELATIONSHIP TO SEVERAL ENVIRONMENTAL FACTORS

Seasonal variations of vesicular-arbuscular mycorrhizal infections and VAM fungal (en- dogonaceous) spore densities were systematically investigated in the rhizospheres of Welsh onion (Allium fistulosum)and corn (Zea mays)in Beijing from 1986 to 1987.The relationships among the occurrence of VAM and VAM fungi,several soil factors (contents of N,P,and organic matters,pH) and climatic factors (soil and atmospheric temperature,accumulated temperature,precipitation,photoperiod and relative humidity) were tentatively evaluated with linear correlation and relational grade.The results obtained showed that mycorrhizal infection rate of the two plants was gradually increased with the extention of their growth period,es- pecially in June and September during the whole year the infection rate was the highest.Spore densities in the rhizospheres of two plants varied greatly,and two peaks appeared in June, July and October respectively throughout the year.In the rhizospheres of Welsh onion and corn in Beijing,the investigated soil factors showed little change during the whole growth pe- riod of plants,so it was considered that climatic factors were more important to the seasonal variations of VAM occurrence in the same region.Analytical results of linear correlation and relational grade indicated that the occurrence of VA mycorrhizae was most closely related to the accumulated temperature during the whole year.