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

摘要:

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。

Abstract:

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.