摘要
在盆栽试验条件下,采用重金属Cd不同浓度的溶液处理土壤,并在玉米拔节—大喇叭口期、大喇叭口—抽雄吐丝期、抽雄吐丝—成熟期进行干旱胁迫处理,研究玉米不同生育期干旱胁迫下重金属Cd不同浓度对土壤中3种微生物(细菌、放线菌、真菌)总数、土壤酶活性和土壤呼吸强度的影响。结果显示:干旱胁迫和重金属Cd不同浓度处理下,土壤中3种微生物的总数、土壤酶活性、土壤呼吸强度差异均达到显著水平。重金属Cd的不同浓度处理对土壤转化酶有抑制作用,而对土壤呼吸强度和土壤过氧化氢酶的影响则随着Cd浓度的增加先促进后抑制。其中当Cd浓度≤5 mg·kg^(-1)对土壤中3种微生物总数和土壤呼吸有促进作用,Cd浓度≥15 mg·kg^(-1)对土壤中3种微生物总数和土壤呼吸有抑制作用;Cd浓度≤1mg·kg^(-1)对土壤过氧化氢酶有促进作用,Cd浓度≥5 mg·kg^(-1)对土壤过氧化氢酶表现出抑制作用,浓度越高抑制作用越明显。土壤中3种微生物总数、土壤过氧化氢酶活性、土壤呼吸强度在玉米不同生育期均与土壤含水量成正相关,而土壤转化酶活性在玉米抽雄吐丝——成熟期受土壤含水量的影响不大,未达到显著水平。总之,玉米生育期中干旱胁迫下重金属Cd不同浓度与土壤微生物、土壤酶活性、土壤呼吸强度密切相关。
Pot experiment was conducted to study the effects of different heavy metal Cd concentrations on soil bioactivity in corn＇s different growth period under drought stress. The soil was treated with different Cd concentrations and drought stressed in corn＇s jointing stage- huge bellbottom period, the huge bellbottom- spinning tasseling stage, the spinning tasseling- mature period. The results showed that drought stress under different concentrations of heavy metal Cd, the total number of three kinds of microbe in soil, soil enzyme activity and soil respiration intensity reached significant level. Different Cd concentrations have different inhibition effects on soil invertase enzyme, but show both promotion and inhibition for soil respiration intensity and the soil catalasewith the change occurred at some threshold values of Cd concentration. For the total number of three kinds of microbe in soil and soil respiration, the Cd concentrations ≤5mg·kg-1have a promoting effect, while the Cd concentrations ≥ 15mg·kg-1have an inhibition effect. For soil catalase, a promoting or an inhibition effect showed with the Cd concentrations lower than 1 mg·kg-1or higher than 5mg·kg-1, respectively. In different development stages of the corn, the total number of three kinds of microbe in soil, soil catalase activity, and soil respiration intensity exhibited positive correlation with soil water content. In contrast, the soil invertase activity in the corn spinning tasseling- mature period is affected little by soil moisture content, and has not reached significant level.
出处
《三峡生态环境监测》
2016年第2期18-24,共7页
Ecology and Environmental Monitoring of Three Gorges
基金
国家自然科学基金项目(31271673)
公益性行业(农业)科研专项(201503127)
关键词
干旱胁迫
重金属CD
土壤微生物
土壤酶活性
土壤呼吸
drought stress
heavy metal Cd
soil microorganism
soil enzyme activity
soil respiration
