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采用盆栽试验培育冬小麦幼苗,待幼苗生长3周、7周和12周时,收集根系土,进行根际土壤细菌、真菌、放线菌、亚硝化菌和自生固氮菌数量的测定。结果表明:冬小麦幼苗生长3周时,Pb2+/Cd2+对根际细菌、自生固氮菌和亚硝化菌表现为显著(p<0.05)抑制作用,平均抑制率分别为20.41%~49.79%、26.62%~76.99%和87.15%~95.88%,而真菌、放线菌数量主要表现为增加,平均增加率分别为0.31%~38.88%和19.58%~113.64%,但微生物总数减少,而多样性指数增加,真菌/细菌比值升高;幼苗生长7周时,放线菌、自生固氮菌和亚硝化菌数量主要表现为增加现象,平均增加率分别为18.16%~19.72%、13.71%~24.59%、2.09%~519.29%,真菌数量降低,平均降低率为9.59%~39.46%,细菌数量在低浓度时增加,高浓度时减少,微生物总数增加,多样性指数主要表现为降低,真菌/细菌比值降低;幼苗生长12周时,Pb2+/Cd2+处理下细菌数量极显著(p<0.01)增加,真菌、放线菌、固氮菌和亚硝化细菌数量降低,平均降低率分别为12.05%~44.66%、1.94%~15.51%、12.44%~55.72%和97.88%~99.00%,微生物总数主要表现为增加,多样性指数降低,真菌/细菌比值极显著降低(p<0.01)。Pb2+/Cd2+处理对冬小麦幼苗根际各类微生物数量、微生物总数和多样性指数及真菌/细菌比值影响显著(p<0.05),且微生物多样性指数的变化主要取决于放线菌数量的变化;Pb2+/Cd2+对冬小麦根际固氮菌和亚硝化菌数量的影响规律不稳定,预示着Pb2+/Cd2+污染将影响其根际土壤N的固定和转化能力,且N源的可利用率不稳定。
The pot experiment was used to cultivate winter wheat seedlings. When the seedlings were grown for 3 weeks, 7 weeks and 12 weeks, root soil was collected for determination of rhizosphere soil bacteria, fungi, actinomycetes, nitrosated bacteria and autotrophic nitrogenous bacteria. The results showed that Pb2 + / Cd2 + had significant (p <0.05) inhibition on rhizobacteria, autotrophic nitrogenous bacteria and nitrosobacteria in winter wheat seedlings with the average inhibitory rates of 20.41% -49.79% and 26.62% 76.99% and 87.15% ~ 95.88% respectively. However, the number of fungi and actinomycetes increased mainly from 0.31% to 38.88% and from 19.58% to 113.64% respectively, but the total number of microorganisms decreased while the diversity index increased. / Bacterial ratio increased. The number of actinomycetes, azotobacter and nitrosomonas increased mainly when the seedlings grew at 7 weeks, the average increase rates were 18.16% -19.72%, 13.71% -24.59%, 2.09% ~ 519.29%, the number of fungi decreased and the average rate of decrease was 9.59% ~ 39.46%. The number of bacteria increased at low concentration, decreased at high concentration and increased the total number of microorganisms, while the diversity index decreased and the ratio of fungi to bacteria decreased. At 12 weeks, the number of bacteria increased significantly with Pb2 + / Cd2 + treatment and the numbers of fungi, actinomycetes, azotobacter and nitrosated bacteria decreased with the average reduction rates of 12.05% -44.66% and 1.94% -15.51 %, 12.44% ~ 55.72% and 97.88% ~ 99.00% respectively. The total number of microorganisms mainly increased, Index decreased, fungi / bacteria ratio was decreased significantly (p <0.01). Pb2 + / Cd2 + treatment had significant effects on the number of rhizosphere microbes, the total number of microbes, the diversity index and fungi / bacteria ratio in winter wheat (P <0.05), and the changes of microbial diversity index mainly depended on the changes of the number of actinomycetes. The effect of Pb2 + / Cd2 + on the number of Azotobacter and nitrosobacteria in rhizosphere of winter wheat was not stable, indicating that Pb2 + / Cd2 + pollution would affect the fixation and transformation ability of N in rhizosphere soils, and the availability of N sources was not stable.