土壤干旱对两品种小麦根际土壤微生物群落组成和酶活性的影响

Effect of soil drought on microbial community composition and enzyme activities in the rhizosphere soils growing two wheat cultivars

采用双因素随机试验,在小麦孕穗期、灌浆期和成熟期研究了土壤干旱对两品种小麦根际土壤微生物丰度、多样性及4种酶活性(蔗糖酶、碱性磷酸酶、脲酶和脱氢酶)的影响。试验设4个处理,即分别在土壤干旱和正常水分下种植小麦"矮抗58"(P1)和"泛麦8号"(P2)。结果表明:与正常水分处理(种植P1和P2)相比,孕穗期,土壤干旱处理下小麦P1和P2根际土中普通细菌、革兰氏阴性细菌的丰度显著降低了11.3%和6.9%、8.4%和8.2%;灌浆期,干旱处理下小麦P1和P2根际土中丛枝菌根真菌的丰度明显下降了34.3%和21.8%;成熟期,干旱处理下小麦P1和P2根际土中革兰氏阳性细菌、真菌的丰度显著降低30.9%和8.6%、34.1%和17.3%。土壤干旱对微生物多样性无显著影响,却显著降低了孕穗期和灌浆期的碱性磷酸酶、脱氢酶活性和灌浆期的蔗糖酶活性,提高了成熟期的蔗糖酶活性。"矮抗58"比"泛麦8号"根际微生物多样性更高,但孕穗期其蔗糖酶活性更低。干旱与品种的交互作用对微生物各类群的丰度、多样性和4种酶活性的影响均不显著。综上,土壤干旱主要抑制微生物丰度,而品种间根际微生物多样性差异明显,干旱和品种均可影响根际土壤的酶活性。

A two-factor randomized trial was conducted to investigate the effect of soil drought on the abundance and diversity of microbes and the activities of four enzymes(sucrase, alkaline phosphatase, urease and dehydrogenase) in the rhizosphere soils growing two wheat cultivars at three growth stages(booting, filling and maturity). Four treatments were set up in the experiment, in which two wheat cultivars“Aikang 58”(P1) and “Fanmai 8”(P2) were planted respectively under two water treatments namely soil drought and normal water. The results showed that compared with normal water treatment(planting P1 and P2), the abundance of common bacteria and gram-negative bacteria in rhizosphere soils of wheat P1 and P2 in drought treatment was significantly decreased by 11.3% and 6.9%, 8.4% and 8.2% at the booting stage, respectively. And then the abundance of arbuscular mycorrhizal fungi decreased significantly by 34.3% and 21.8% in rhizosphere soils of wheat P1 and P2 in drought treatment at the filling stage, respectively. At the maturity stage, the abundance of gram-positive bacteria and fungus decreased significantly by 30.9% and 8.6%, 34.1% and 17.3% in the rhizosphere soils of wheat P1 and P2 in drought treatment, respectively. Soil drought had no significant effect on microbial diversity, but significantly decreased the activities of alkaline phosphatase and dehydrogenase at the booting and filling stages and the activity of sucrase at the filling stage, and increased the activity of sucrase at the maturity stage.The microbial diversity in the rhizosphere soil planting “Aikang 58” was higher than that of “Fanmai 8”, but its sucrase activity was lower at the booting stage. The interaction of soil drought and wheat cultivar had no significant effect on the microbial abundance, diversity and four enzyme activities.In conclusion, soil drought mainly inhibited microbial abundance, and there was significant difference in microbial diversity in the rhizosphere soils?of two wheat cultivars. Both soil drought and wheat cultivar affected soil enzyme activities.