Cd污染及其与大气CO2浓度升高、N添加复合作用对大叶相思生长的影响

Growth Dynamics of Acacia auriculiformis under Cadmium Pollution and Its Combination with Atmospheric CO2 Enrichment and Nitrogen Addition

为了解Cd污染胁迫下树木对CO2浓度升高、N添加及其复合作用的响应,应用开顶箱,探讨Cd及其与CO2、N的复合作用对大叶相思(Acacia auriculiformis)基径、树高和生物量的影响。结果表明,Cd添加抑制大叶相思基径、树高和生物量的增长,并且具有时间滞后性;大气CO2浓度升高、N添加及CO2+N均有缓解Cd对植物生长抑制作用的趋势,其中,N添加更能促进大叶相思基径的生长,树高生长则对CO2升高更为敏感;在Cd污染土壤中,N添加的缓解作用最显著。因此,氮肥管理是重金属污染土地修复初期促进植物修复的重要策略。

In order to understand the response of trees to elevated CO2,N addition and Cd stress,the growth characters of Acacia auriculiformis,such as basal diameter,tree height and individual biomass,were studied using an open-top chamber(OTC).The results showed that the basal diameter,height and individual biomass of A.auriculiformis were significantly inhibited under Cd stress,and the inhibition effect was with a lag time.Both elevated CO2 and N addition remitted the inhibition of Cd stress on A.auriculiformis growth,N addition could promote the base diameter growth of A.auriculiformis,and tree height growth was more sensitive to CO2 enrichment.Under Cd stress,the biomass accumulation of A.auriculiformis was mainly caused by N addition.So,it was suggested that N fertilization management was an important strategy to promote phytoremediation in the early stage of heavy metal contaminated land remediation.