Cu Cd Pb Zn对酸性耕作土壤3种酶活性的影响

The Effects of Cu,Cd,Pb and Zn on the Activities of Urease,Protease and Peroxidase in Acid Cultivated Soil

采用添加外源重金属和室内培养的方法,研究了Cu、Cd、Pb、Zn对1个酸性耕作土壤中脲酶、蛋白酶和过氧化物酶活性的影响。Cu添加浓度为50、100、200、400、600mg·kg-1,Cd添加浓度为1、5、10、15、20mg·kg-1,Pb添加浓度为100、300、500、800、1200mg·kg-1,Zn添加浓度为50、100、200、400、800mg·kg-1。结果表明,Cu、Cd、Pb、Zn对脲酶以抑制作用为主,4种重金属对酶毒性大小依次为Cu>Cd>Zn≥Pb,但在培养末期抑制作用都趋于减弱。Pb、Cu、Cd、Zn在前17d的培养中使蛋白酶酶活性急剧降低,以后蛋白酶活性维持在此较低水平上。短时间内(3d)Zn对过氧化物酶具有强烈的抑制作用,但总体看来4种重金属对过氧化物酶活性的影响均较小。上述结果表明,脲酶对农田土壤Cu污染具有指示作用,蛋白酶对农田土壤4种重金属污染都具有指示作用,过氧化物酶仅对土壤Zn的短期污染具有指示作用。

The influence of Cu, Cd, Pb, Zn addition on the activities of urease, protease and peroxidase in an cultivated soil was studied by indoor incubation. The added dose is 50, 100, 200, 400, 600 mg·kg^-1 for Cu, 1, 5, 10, 15, 20 mg·kg^-1 for Cd, 100, 300, 500, 800, 1 200 mg·kg^-1 for Pb, 50, 100, 200, 400, 800 mg·kg^-1 for Zn, respectively. The results showed that Cu, Cd, Pb and Zn mainly inhibited the activity of urease of which the inhibition effect decreased in the order of Cu〉Cd〉Zn ≥Pb. The inhibition of the four metals on the the activity of urease weakened during the final incubation period. The activity of protease was decreased dramatically in the early 17 days of incubation by adding the four metals and maintained the low activity afterwards. The four metals showed relatively weak inhibition effects on the activity of peroxidase except for Zn which markedly decreased the peroxidase activity in the early three days. The above results suggested that the activity of urease could be the indicator of soil Cu pollution, that of protease could be the indicator of Cu, Cd, Pb and Zn pollution of soil, and that of peroxidase could only indicate short-term Zn pollution of soil.