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通过盆栽实验研究了外源稀土元素La对茶园紫色土脲酶、蔗糖酶、纤维素酶及脱氢酶活性的影响。结果表明:低浓度(≤300 mg·kg-1)La3+对茶园紫色土脲酶活性、蔗糖酶活性、纤维素酶活性具有显著促进作用(p<0.05),而高浓度(≥800 mg·kg-1)则呈现显著的抑制作用(p<0.05)。脲酶、蔗糖酶和纤维素酶最优促进浓度分别为100,300和300 mg·kg-1,抑制浓度分别为800,800和600 mg·kg-1。随培养时间延长,La3+对茶园紫色土脲酶、蔗糖酶、纤维素酶刺激作用有减缓趋势。各浓度La3+处理对茶园紫色土脱氢酶均呈显著抑制作用(p<0.05),随浓度升高抑制作用逐步增强,随着培养时间延长,抑制作用有减缓的趋势。相关分析结果表明:脲酶分别与蔗糖酶和纤维素酶呈现极显著正相关(p<0.01),蔗糖酶与纤维素酶亦呈现极显著正相关(p<0.01),脱氢酶与脲酶、蔗糖酶、纤维素酶相关性不显著。脱氢酶活性可以作为评价稀土元素污染茶园紫色土土壤环境的敏感指标。
Pot experiments were conducted to study the effects of exogenous rare earth element La on urease, invertase, cellulase and dehydrogenase activity in purple soil of tea plantation. The results showed that low concentrations (≤300 mg · kg-1) of La3 + had significant effects on urease activity, invertase activity and cellulase activity of tea plantation (p <0.05), while high concentration (≥800 mg · kg- 1) showed a significant inhibitory effect (p <0.05). The optimal promoting concentrations of urease, invertase and cellulase were 100, 300 and 300 mg · kg-1, respectively, and the inhibitory concentrations were 800, 800 and 600 mg · kg-1, respectively. With the prolongation of culture time, La3 + tended to reduce the purple urease, invertase and cellulase activities in tea plantation. The concentration of La3 + significantly inhibited the purple soil dehydrogenase in tea plantation (p <0.05). With the increase of concentration, the inhibitory effect gradually increased. With the prolongation of culture time, the inhibitory effect slowed down. Correlation analysis showed that there was a significant positive correlation between urease and sucrase and cellulase (p <0.01), sucrose and cellulase also showed a significant positive correlation (p <0.01), dehydrogenase and urease, sucrose The correlation between enzyme and cellulase was not significant. Dehydrogenase activity can be used as a sensitive index to evaluate the environmental pollution caused by rare earth elements in purple soil of tea plantation.