中文摘要：

为了研究镉胁迫诱导满江红体内花青素合成的生理功能，采用镉诱导和体外实验的方法评价了满江红体内花青素的抗氧化作用．测试指标包括还原力、清除超氧阴离子（O2^-）、过氧化氢（H2O2）、羟自由基（·OH）的能力．结果表明，花青素的还原力和对氧自由基的清除作用随花青素提取物浓度的增加而增加．因此，镉胁迫下合成的花青素是一种清除活性氧自由基的良好抗氧化剂．镉胁迫对满江红活性氧代谢影响的试验结果表明，在0．5mg·L^-1 Cd胁迫下，满江红体内O2^-和H2O2大量积累，造成活性氧胁迫，说明花青素只能在一定程度上保护满江红免受过氧化伤害．本实验初步证实，花青素含量的增加是满江红抗性机理之一，可缓解镉的毒害。

英文摘要：

To investigate the physiological function of anthocyanins which are induced by cadmium in Azolla imbricata, the in vitro antioxidant properties of anthocyanins were investigated using different testing indexes, including reducing power, superoxide anion radical （O2^-）scavenging, hydrogen peroxide（H2O2 ）scavenging and hydroxyl radical（·OH）scavenging. The scavenging activity of reactive oxygen species, as well as the reducing power increased with increasing concentrations of anthocyanin extracts. Thus, anthocyanins induced under Cd stress have an inherent potential to function as effective antioxidants by scavenging reactive oxygen species. We also investigated the effects of Cd on active oxygen metabolism in the fronds of A. imbricata. The results showed that 0.5mg· L^-1 Cd treatment resulted in excessive accumulation of O2^- - and H2O2 , by imposing active oxygen stress. The data b.ere suggest that anthocyanins might partially protect the fronds from oxidative damage. Based on these results, an increase in the content of anthocyanins is considered one of the resistance mechanisms of A. imbricata toward Cd toxicity.