Cd2＋胁迫对竹叶眼子菜的毒理学效应分析  

Phytotoxicity of Cd^(2+) on Leaf Cells of Potamogeton malaianus

作　　者：杨海燕[1] 施国新[1] 徐勤松[1] 计汪栋[1] 王红霞[1] 李阳[1] 

机构地区：[1]南京师范大学生命科学学院,江苏省生物多样性与生物技术重点实验室,南京210046

出　　处：《应用与环境生物学报》2008年第3期366-370,共5页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目资助(Nos.30370083,30670121);高等学校博士学科点专项科研基金项目资助(No.20050319005)~~

摘　　要：以不同浓度Cd2+处理5d的竹叶眼子菜为实验材料,分析了叶片的光合色素、抗氧化系统、丙二醛(MDA)、可溶性糖、可溶性蛋白等生理生化指标的应答反应,并用透射电镜观察了叶细胞超微结构的变化.随着Cd2+处理浓度的增加,叶绿素含量和超氧化物歧化酶(SOD)活性下降,而MDA和可溶性糖含量上升;过氧化氢酶(CAT)、过氧化物酶(POD)活性和抗坏血酸(ASA)、还原型谷胱甘肽(GSH)含量分别在2mgL-1和4mgL-1时达到峰值;可溶性蛋白含量下降,相对分子质量(Mr)为52.1×103、42.9×103、27.4×103和14.1×103的多肽合成量逐渐减少,但Mr为18.1×103的多肽的合成量增加;叶绿体膨大、解体;线粒体嵴突肿胀、空泡化;核仁分散、核膜断裂、核质散出.结果表明:Cd2+对竹叶眼子菜的光合结构、细胞保护系统以及细胞结构的完整性等都产生明显破坏作用,最终将导致植物死亡.其中SOD、叶绿素和蛋白生物合成各指标的反应较灵敏,可作为水体Cd2+污染的监测指标.Cd2+对竹叶眼子菜的半效应浓度为2.97mgL-1.The toxic effects of different gradient concentrations of Cd2＋ （0, 2, 4, 6 and 8 mg·L^-1 ） on chlorophyll content, anti-oxidase system ,＂ MDA content, soluble sugar content, soluble protein content and ultrastructure of the cells of Potamogeton malaianus were studied. With Cd2＋ increasing, the chlorophyll content, soluble protein content and the activity of superoxide dismutase （SOD） decreased drastically, while the MDA content and soluble sugar content increased. The activities of catalase （CAT） and peroxidase （POD） increased, and when reached at 2 mg ·L^ -1 they decreased then. Glutathione （GSH） and ascorbic acid （ASA） content increased, and decreased after 4 mg· L^-1. SDS-PAGE revealed that Cd2＋ reduced the amounts of four polypeptides with apparent molecular weights as 52.1 ×10^3 , 42.9 ×10^3 , 27.4 ×10^3 and 14.1 ×10^3 , respectively, while it promoted the expression of one polypeptide with apparent molecular weight 18.1 ×10^3. Ultrastructural observation showed that the uhrastructural damage was much more serious at higher pollutant concentration. This resulted in swelling of chloroplast, disruption and disappearance of chloroplast membrane, disintegration of chloroplasts, dilatation of cristae, deformation and vacuolization of mitochondria, condensation of chromatin in nucleus, dispersion of nucleolus, and disruption of nuclear membrane and nucleoplasm flowing into cytoplasm. Generally, the response of SOD, chlorophyll and soluble protein was most sensitive to Cd2 ＋ toxicity, which could be recommended as bio-rnonitoring indicator of Cd2＋ pollution in water body. The EC50 of Cd2＋ to P. malaianus was 2.97 mg·L^ -1 based on the experiment results.

关 键 词：竹叶眼子菜 CD2+胁迫 抗氧化系统 超微结构 

分 类 号：X173[环境科学与工程—环境科学]