Abstract: Through simulative methods, the influences of water and lead on the soil urease, glucose, phosphatase activity of soil were studied. A certain extent water stress had a remarkably activated effect on soil urease, glucose, phosphatase activity. Glucose was the most sensitive to the change of soil water content. The effect of lead on glucose showed activation at low concentration and inhibition at high concentration, while the inhibiting effects on urease and phosphatase increased with the aggravation of lead. The inhibition rate achieved 56.31%,53.21% and 38.11% respectively when 2000 mg·kg^-1lead concentration. There existed generally mutual action between soil water content and lead. Under mild water stress, the joint of water and lead stress had antagonism to urease; while had synergism at low lead concentration and had antagonism when lead concentration was higher than 1000 mg·kg^-1 to glucose; and had synergism to phosphatase as lead concentration was 300 mg·kg^-1. Light water stress interacting with lead demonstrated synergism to urease, glucose, antagonism to phosphatase. Under sever water stress, net varying amounts (ΔU) was lower than zero only at 2000 mg·kg^-1 of lead concentration. The joint stress of water and lead induced the greatest ΔU of soil enzyme were 88.4%, 50.7% and 25.5% of control.

Key words: Lead, Water stress, Lou soil, Soil enzyme activity

摘要： 针对西北旱区铅锌矿业废弃地林、草植被恢复以及重金属铅污染土壤的植物修复问题,以杨凌塿土土壤为研究对象,通过模拟方法分析水分和铅单一及双重胁迫对土壤脲酶、蔗糖酶、碱性磷酸酶活性的影响。结果表明:一定程度的水分胁迫对土壤酶具有激活作用,蔗糖酶对土壤含水量变化最为敏感;蔗糖酶在低铅浓度时被激活、高浓度时被抑制,脲酶和碱性磷酸酶随铅浓度增加保持持续下降趋势。当铅浓度为2000 mg·kg^-1时,3种酶的最大抑制率分别为56.31%,53.21%和38.11%。水分和铅浓度之间存在交互作用,轻微水分胁迫下,水分和铅双重胁迫对土壤脲酶活性表现出拮抗作用;低浓度铅对土壤蔗糖酶表现出协同作用,铅浓度大于1000 mg·kg^-1时表现出拮抗作用;对土壤碱性磷酸酶仅在300 mg·kg^-1时表现出协同作用。轻度水分胁迫和铅对土壤脲酶和蔗糖酶主要表现为协同作用,对碱性磷酸酶主要表现为拮抗作用;重度水分胁迫下,碱性磷酸酶净变化量(ΔU)仅在铅浓度为2000 mg·kg^-1时小于0,脲酶和蔗糖酶的ΔU规律不明显。水分与铅交互作用下,各种酶最大ΔU分别为对照的88.4%,50.7%和25.5%。

关键词: 铅(Pb), 水分胁迫, 塿土, 土壤酶活性