凋落物管理对樟子松人工林土壤微生物群落结构的影响

Effects of litter manipulation on soil microbial community structure in a Pinus sylvestris var. mongolica plantation

采用磷脂脂肪酸法(PLFA)分析短期(18个月)凋落物管理对樟子松人工林土壤微生物群落结构的影响。结果表明,凋落物移除对土壤各类微生物的PLFAs均无显著影响,但凋落物加倍显著改变了土壤微生物群落结构。凋落物加倍显著提高了土壤PLFAs总量、革兰氏阳性细菌(G+)与革兰氏阴性细菌(G-)和原生动物PLFAs,但对真菌和放线菌PLFAs以及细菌/真菌值、G+/G-值影响不显著。凋落物加倍使土壤总PLFAs上升了82.4%,细菌PLFAs上升了93.9%。凋落物管理对樟子松人工林土壤微生物的Shannon多样性指数、Pielou均匀度指数和Simpson优势度指数均无显著影响。主成分分析表明,主成分1(89.83%)上得分系数较高的PLFAs多为细菌的特征PLFAs,主要有16:1ω5c、16:1ω7c、cy17:0ω7c、cy19:0ω7c、i14:0、i15:0。

We used phospholipid fatty acid（ PLFA） method to analyze the effects of short-term（ 18 months） litter manipulation on soil microbial communities in a Pinus sylvestris var. mongolica plantation. The results showed that removing litter had no significant effect on soil microbial PLFAs,but doubling litter significantly changed the soil microbial community structure. Specifically,doubling litter significantly improved the total PLFAs of soil microbes,PLFAs of Gram-positive bacteria（ G＋）,Gram-negative bacteria（ G-）,and protozoon,but had no significant effects on the PLFAs of fungi and actinomycetes,and on the ratios of bacteria / fungi and G ＋ / G-. Soil total microbial PLFAs and bacterial PLFAs increased by 82. 4% and 93. 9% by doubling litter,respectively. The Shannon＇s diversity index,Pielou＇s evenness index,and Simpson＇s dominance index were not influenced by litter manipulation. Principal components analysis（ PCA）still indicated that litter manipulation changed the soil microbial community structure. PC1（ 89.83%） was mainly contributed by PLEAs of bacteria,including 16： 1ω5c,16： 1ω7c,cy17： 0ω7c,cy19： 0ω7c,i14： 0,and i15： 0.