白骨壤幼苗对镉胁迫的生长及生理生态响应

The Growth and Ecophysiological Responses of Mangrove Avicennia marina Seedlings to Cadmium

采用砂基栽培,研究重金属镉(Cd)不同胁迫质量浓度(0,0.5,5,25,50,100和150mg/L)和胁迫时间(45和90d)条件下,对白骨壤(Avicennia marina)幼苗生长以及生理生态的影响(包括叶绿素含量、根尖及叶片的丙二醛(MDA)含量、抗坏血酸(ASA)含量、可溶性蛋白含量、超氧化物歧化酶(SOD)活性以及过氧化物酶(POD)活性等).结果表明:在Cd胁迫下,幼苗萌芽有一定程度的延迟,当Cd胁迫质量浓度≥25mg/L时导致叶片受害并显著抑制茎的生长,≥50mg/L时可导致幼苗死亡,成活率随着胁迫质量浓度提高而降低;幼苗各器官及全株生物量均随着Cd胁迫质量浓度提高而降低;低质量浓度的Cd(≤25mg/L)对叶片叶绿素的合成具有一定的促进作用,而高质量浓度的Cd则会导致叶绿素含量降低;Cd胁迫能显著提高幼苗根尖和叶中的ASA含量,并降低MDA含量,同时Cd胁迫对根尖和叶中的可溶性蛋白含量、SOD及POD活性具有不同程度的促进作用.

Avicennia marina seedlings were treated with various contents （0.5,5,25,50,100,150 mg/L） of cadmium （Cd）, and cul- tivated by man-made seawater with salinity of 15 in sand for 90 days in a greenhouse. The growth and ecophysiological responses to Cd stress were investigated at the 45th day and the 90th day. The results were as follows：The germination of seedlings was delayed by Cd stress. When at the concentration of 25 mg/L and above,Cd had a poisonous effect on leaves and also showed a significant inhi- bition on the growth of stem. Some of the seedlings were dead and the survival rate decreased when the concentration of Cd was high- er than 50 mg/L. In addition,the chlorophyll content increased at low Cd levels （≤25 mg/L） ,but decreased at higher Cd levels. With increasing the concentration of Cd, the biomass of various parts of the seedling and the total biomass decreased. The ascorbic acid （ASA） content in leaves and roots obviously increased while the malondialdehyde （MDA） content decreased with the Cd treatment. The content of soluble protein,the activity of superoxide dismutase （SOD） and peroxidase （POD） in leaves and roots obviously in creased with treatments of increasing Cd contents.