锌胁迫对水花生生长和土壤酶活性的影响

Effects of Zn Stress on the Growth of Alternanthera philoxeroides and Activities of Soil Enzymes

通过盆栽实验,研究了不同浓度锌胁迫对外来杂草水花生(Alternanthera philoxeroides)植株生长、叶绿素含量、土壤pH值、电导率及土壤酶活性的影响。结果表明,锌胁迫条件下,水花生植株地上部分外观伤害随锌处理浓度升高伤害加重;锌处理浓度>100 mg.kg-1时水花生植株高度、最长根长、平均根长、平均根数降低;叶绿素a和叶绿素b含量均表现为锌处理浓度≤200 mg.kg-1时升高,锌处理浓度>200 mg.kg-1时降低的现象;土壤电导率随锌浓度的增高而升高,土壤pH值、脲酶、蔗糖酶、过氧化氢酶和多酚氧化酶活性均随着锌浓度增加均逐渐减小,与锌浓度有高度相关性。4种土壤酶对锌污染的敏感性表现为:磷酸酶>蔗糖酶>脲酶>过氧化氢酶。

The toxic effects of Zn on plant growth and chlorophyll content of an exotic species, Alternanthera philoxeroide , as well as on soil pH values, electrical conductivity and activities of four soil enzymes were studied in a pot experiment. The results showed that the apparent injury of Zn to the aerial part of A. philoxeroide became more and more conspicuous with increasing concentrations; the plant growth, maximal and average root length as well as average root numbers all decreased at the Zn concentration above 100 mg·kg^-1; the contents of chlorophyll a and b increased at a concentration ≤200 mg·kg^-1 but decreased above 200 mg·kg^-1; the soil electrical conductivity increased with increasing Zn concentration, while the soil pH values as well as the activities of urease, calatase, sucrase and phosphorylase activities was all decreased, suggesting a highly negative correlation with Zn concentrations. The susceptibility of the four soil enzymes studied to Zn pollution was phosphorylase, sucrase, urease and calatase deseendingly.