【摘要】 采用盆栽试验研究了土壤—水稻系统中不同铅浓度下(CK,100,300,500,700,900 mg/kg)2种水稻土壤的酶活性、微生物量碳、水稻生理指标及生物量的变化。结果表明:低浓度的铅处理时,土壤酶活性、微生物量碳及水稻生物量有一定的激活效应,而当铅浓度超过500 mg/kg时,多数指标转为抑制作用,其影响程度受土壤性质(如颗粒组成,有机质含量等)制约。水稻叶绿素含量在黄松田水稻土中开始随铅处理浓度的增大而增加,到铅浓度达700 mg/kg时出现峰值,然后随铅浓度的增加而降低;而在黄红壤水稻土中变化差异不明显。铅处理诱导了水稻中脯氨酸含量和过氧化物酶活性的缓慢上升。种植水稻比未种水稻具有较高的土壤微生物量碳,揭示了水稻生长具有一定的解毒作用。在土壤—铅—水稻相互作用的系统中,土壤酶活性、土壤微生物量和水稻生理指标是较好地反映铅污染的敏感指标,并且相互间存在一定的相关性,其大小因土壤类型而异。更多还原

【Abstract】 The effect of lead (Pb) treatment on the soil enzymatic activities,soil microbial biomass,rice physiological indices and rice biomass in soil-rice system were studied by pot experiment in a greenhouse. Lead was applied at 0(CK),100,300,500,700,900 mg/kg levels in two different paddy soils.The results showed that low Pb concentration had a stimulating effect on soil enzymatic activities,microbial biomass car- bon (Cmic) and rice biomass,and an inhibitory influence on most indices when Pb concentration over 500 mg/kg and the influence also restricted by soil properties (e.g.size composition,organic matter content). Rice Chorophyll content increased with Pb level and appeared a peak at 700 mg/kg Pb concentration,then decreased with Pb level in Silty loam,however,no evident difference in Yellowish red soil.Pb was effective in indueing proline accumulation and its toxicity caused oxidative stress on rice plants.Higher soil Cmic with planting rice than with no rice indicated rice growth definite detoxification.On the whole,Soil enzymatic ac- tivities,Cmic and rice physiological indices,therefore,may be sensitive indicators reflecting environmental stress in soil-Pb-rice system.And the correlations among them followed soil types.更多还原