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

为了解Cd污染胁迫下树木对CO_2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CO_2、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CO_2浓度升高、N添加及CO_2+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CO_2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。

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

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.