Cd、豆磺隆胁迫下黑土-小麦系统中酶活性的动态变化

利用盆栽试验研究了Cd单一污染和Cd-豆磺隆复合污染作用下黑土-小麦系统中脲酶(Urease)和过氧化氢酶(CAT)活性的动态变化,尤其是考察了小麦整个生育期内(主要分为拔节期、开花期和成熟期)这2种酶活性的动态变化规律.结果表明,无论是在有或无豆磺隆胁迫时,随着Cd污染浓度的增加,脲酶活性呈现出明显的下降趋势,过氧化氢酶活性变化相对于脲酶比较稳定.通过拟合方程可知,脲酶和过氧化氢酶活性变化在一定程度上可以反映Cd或Cd-豆磺隆的污染状况,如果用酶活性指示Cd和豆磺隆污染程度时需适当考虑作物的不同生育期以及Cd和豆磺隆污染的关系.在小麦的整个生长期内,当Cd含量为2～30 mg·kg-1时,无论是Cd单一污染还是Cd-豆磺隆复合污染,脲酶活性均呈现出由拔节期到开花期升高、由开花期到成熟期下降的趋势;而在高含量(＞30 mg·kg-1)Cd作用下,酶活性的这种变化趋势表现的较弱.

Dynamic changes in the activity of urease and CAT in phaiozem-wheat systems under the stress of Cd and chlorimuron-ethyl

Dynamic changes in the activity of catalase (CAT) and urease in phaiozem-wheat systems with single stress of cadmium (Cd) or joint stress of Cd and chlorimuron-ethyl were studied using the pot-culture experiment. In particular, their activity at the jointing stage, florescence stage and mature stage was observed. The results showed that the activity of urease decreased with increasing concentration of soil Cd whether chlorimuron-ethyl was added or not. However, there was only a weaker change in the activity of CAT compared with the activity of urease. According to the regression equations, the activity of urease and CAT can be a good index to indicate the degree of soil pollution by Cd and chlorimuron-ethyl if considering the correlation of concentration of Cd and chlorimuron-ethyl and the activity of the two enzymes during different growth periods of wheat plants. In the whole growth period of wheat, the activity of the two enzymes both by stress of single Cd and joint stress of Cd and chlorimuron-ethyl increased from the jointing stage to the florescence stage, and decreased from the florescence stage to the mature stage when the concentration of Cd was 2.0~30 mg?kg-1. but kept rising at the three growth periods under the stress of high concentration (> 30 mg?kg-1) of soil Cd.