两个品种玉米根际土壤微生物和酶活性对水分胁迫的响应

Responses of soil microbe and enzyme activities to water stress in the rhizosphere of two cultivars maize

利用双因素随机试验研究在玉米3个生育期(大喇叭口期、灌浆期和成熟期)水分胁迫对2个品种玉米根际土中微生物的丰度、多样性、群落结构及酶活性(蔗糖酶、脲酶、碱性磷酸酶和脱氢酶)的影响。试验设4个处理,即在水分胁迫和正常供水下分别种植2个玉米品种(“郑单958”和“农华101”)。结果表明:水分胁迫显著抑制了3个生育期根际土中革兰氏阴性细菌和丛枝菌根真菌的丰度以及成熟期的普通细菌和革兰氏阳性细菌丰度,并提高了微生物的均匀度,使群落结构发生明显改变。水分胁迫显著降低了灌浆期根际土中脱氢酶活性、成熟期的碱性磷酸酶和脱氢酶活性;显著提高了成熟期的蔗糖酶活性。灌浆期,“农华101”比“郑单958”根际土中丛枝菌根真菌丰度和脱氢酶活性高,但其微生物多样性和均匀度却较低。水分与品种的交互作用仅对灌浆期根际土中放线菌丰度、灌浆期和成熟期的丛枝菌根真菌丰度和3个生育期的微生物群落结构有显著影响。

A two-factor randomized experiment was conducted to investigate the effects of water stress on microbial abundance,diversity,community structure and enzyme(sucrase,urease,alkaline phosphatase and dehydrogenase)activities in the rhizosphere soils of two cultivars maize in three periods(flare opening,filling and maturity).Four treatments were set up,that is,two maize cultivars(“Zhengdan 958”and“Nonghua 101”)were planted under water stress and normal water supply,respectively.The results showed that water stress significantly inhibited the abundance of gram-negative bacteria and arbuscular mycorrhizal fungi in rhizosphere soils in three periods and the abundance of common bacteria and gram-positive bacteria in maturity period.The evenness index of microbe increased and the community structure changed obviously under water stress.Under water stress,dehydrogenase activity in filling period and the activities of alkaline phosphatase and dehydrogenase in maturity period significantly decreased,and sucrase activity in maturity period significantly increased.The abundance of arbuscular mycorrhizal fungi and dehydrogenase activity in the rhizosphere soil of“Nonghua 101”were higher than that of“Zhengdan 958”,but the diversity and evenness of microorganisms were lower in filling period.The interaction of water and cultivar only had significant effects on the abundance of actinomyces in filling period and that of arbuscular mycorrhizal fungi in filling and maturity periods and microbial community structure in three periods.