Cd胁迫对3种蕨类植物生理代谢及镉累积特性的影响

Effects of Cd Stress on the Physiological and Accumulating Characteristics of Three Pteridophyta Plants

通过盆栽试验,对Cd胁迫下3种蕨类植物江南卷柏(Selaginella moellendorffii)、紫萁(Osmunda japonica)和蜈蚣草(Pteris vittata)的生长、生理和重金属累积与分布情况进行研究。结果表明,在较高浓度Cd处理下,3种植物的株高、鲜重和地上与地下部分的干重比都受到抑制,浓度越高,抑制越明显;随着Cd处理浓度的增加,3种蕨类植物叶绿素含量随胁迫浓度的增加先上升后下降;MDA含量均有不同程度的增加,在Cd浓度≥50mg/kg,与对照相比,江南卷柏和蜈蚣MDA含量增加不明显(p>0.05),而紫萁MDA含量显著增加(p<0.05);脯氨酸含量均随处理浓度的增加而增大;江南卷柏和紫萁SOD活性均随处理浓度的增加先升高(Cd=50mg/kg,达到最大值)后降低,蜈蚣草SOD活性随处理浓度的增加而增大;江南卷柏和紫萁POD活性随处理浓度的增加而增大,蜈蚣草POD活性随处理浓度的增加而先上升后下降,在Cd浓度为100mg/kg时达到最大值;3种蕨类植物CAT活性总体上随胁迫浓度的增加先上升后下降。在Cd浓度≤50mg/kg时,紫萁对重金属Cd的累积能力最强,但在高浓度镉胁迫时,紫萁的耐性要低于江南卷柏和蜈蚣草。综合各个指标变化情况来看,3种蕨类植物对重金属Cd的抗性排序为江南卷柏>蜈蚣草>紫萁。

The effects of Cd stress under different treatment concentration on the growth, physiological and accumulating characteristics of three pteridophyta plants （Selaginella moellendorffii, Osmunda japonica, Pteris vittata） were studied by a pot experiment. The results showed that with the increase of Cd concentra- tion, the plant height, fresh weight and ratio of shoot to root dry mass were inhibited. The chlorophyll con- tent increased in the beginning, and then decreased with increasing Cd concentrations. The contents of MDA and proline increased with increasing Cd concentrations. Compared with the control, at Cd≥50 mg/kg, the MDA content of O. japonica increased significantly （p〈0.05）, while the MDA contents of S. moellendorffii and P. vittata had no significant difference （p〉0.05）. With increase of Cd concentrations, the activity of SOD of S. moellendorffii and O. japonica increased first （when Cd =50 mg/kg, it reached maximum）, and then decreased, while the activity of SOD of P. vittata increased gradually. The activity of POD of S. moellendorffii and O. japonica increased with increasing Cd concentrations, while the activity of POD of P. vittata increased the first （when Cd = 100 mg/kg, it reached maximum）, and then decreased. The activity of CAT of three pteridophyta plants increased firstly and then decreased as a whole. At Cd-50 mg/kg, the ability of accumulation of O. japonica was higher than that of S. moellendorffii and P. vittata. Under high Cd concentration stress, the tolerance capacity of O. japonica was lower than that of S. moellendorffii and P. vittata. Based on the overall consideration of changes of the indicators, the capacity of tolerance to Cd was presented in the order S. moellendorffii〉P, vittata〉O, japonica.