重金属铅镉对玉米生长及土壤微生物的影响

采用温室盆栽土培方法.研究了土壤中不同浓度重金属铅(Pb,0-800 mg·kg~(-1))、镉(Cd,0-50 mg·kg~(-1))单一及其复合处理对玉米(Zea mays L.)生长及土壤微生物(细菌、放线菌、真菌)数量的影响.结果表明,在重金属Pb、Cd单一及其复合处理下,玉米的株高、干重均低于对照,重金属Pb、Cd处理对玉米的生长存在负面影响.重金属Pb、Cd单一处理抑制细菌、真菌的生长,中低浓度Pb(<300mg·kg~(-1))、Cd(≤10mg·kg~(-1))单一处理促进放线菌数量的增加,高浓度(Pb≥800mg·kg~(-1)、Cd≥50mg·kg~(-1))则呈现抑制效应;Pb、Cd复合在高中低浓度下都抑制土壤微生物生长,减少微生物数量.玉米株高同土壤微生物之间相关性不显著;玉米干重同土壤细菌、真菌显著相关,同土壤放线菌之间相关性不显著.

Effects of Heavy Metals Lead and Cadmium on Zea mays L.Growth and the Soil Microorganism

Pot experiment was conducted to study the effects of different concentrations of lead (Pb, 0-800 mg·kg~(-1)), cadmium (Cd,0～50 mg·kg~(-1)) single and their compound treatments on growth of maize (Zea mays L.) and soil microbe quantity including bacteria, actino-mycetes, fungi. The results showed that the heavy metals Pb and Cd treatment have the negative influence on maize growth, plant height and drymass of maize were significantly lower than that of the control under Pb、Cd single and compound treatments. The Pb、Cd single treatment inhibited the growth of bacteria and fungi; Actinomycetes was increasing under middle and low concentration of Pb (blow 300 mg·kg~(-1))、Cd (blow 10 mg·kg~(-1)), while the high-concentration (Pb above 800 mg·kg~(-1)、Cd above 50 mg·kg~(-1)) presented the inhibitory effect; Growth of Soil microorganism was inhibited under the high 、 middle and low concentration of Pb and Cd compound treatments, and caused the microbe quantity decreased. The relationship between maize plant height and the soil microorganism wasn't related significantly; There was significant correlation among maize drymass and soil bacteria 、fungi, but not and the soil actinomycetes.