外源亚精胺可缓解荇菜镉毒害  

Exogenous Spermidine Can Mitigate the Poison of Cadmium in Nymphoides peltatum

作　　者：李阳[1] 施国新[1] 王红霞[1] 赵娟[1] 袁秋红[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：《植物学报》2009年第5期571-577,共7页Chinese Bulletin of Botany

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

摘　　要：研究了外施浓度为0.01mmol.L-1的亚精胺(Spd)对不同浓度镉(Cd2+)胁迫下荇菜(Nymphoides peltatum)叶片的叶绿体结构、叶绿素含量、可溶性蛋白含量、超氧阴离子(O2-.)产生速率和丙二醛(MDA)含量,以及保护酶——超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的影响。结果表明,(1)Cd2+胁迫可使荇菜细胞的叶绿体结构遭到破坏,叶绿素含量减少。外施Spd则可有效地保护叶绿体结构,减少叶绿素的流失。(2)在单一Cd2+处理条件下,随着Cd2+浓度的升高,叶绿素含量呈现先升后降的趋势,可溶性蛋白含量则逐渐下降。外源Spd处理显著提高了二者的含量,并延缓了它们的下降速度。(3)在单一Cd2+处理条件下,SOD、POD和CAT活性分别在Cd2+浓度为1、1和2mg.L-1时达到最高值,而后随着Cd2+浓度的增加其活性逐渐下降。外施Spd使它们的活性分别提高了5.8%、37.5%和3.3%,并降低了O2-.产生速率和MDA的含量。上述结果表明,Spd增强了荇菜对Cd2+毒害的抗性,并在一定程度上缓解了Cd2+对荇菜的毒害。This study focused on the changes in chlorophyll content, soluble protein content, O2^＋ generating rate, MDA content and activity of protective enzymes （SOD, CAT, POD） in leaves of Nymphoides peltatum under different concentrations of Cd^2＋ stress with 0.01 mmol·L-1 exogenous spermidine. Transmission electron microscopy revealed that Cd^2＋ imposed injury on the ultrastruc- ture of chloroplasts, with swelling, breakage and disappearance of the chloroplast envelope and reduced chlorophyll content. Spermidine treatment effectively protected the ultrastructure of chloroplasts against Cd^2＋ stress and maintained the arrangement of thylakoids. Under single Cd^2＋ stress, with Cd^2＋ increase, chlorophyll content in N. peltatum increased then decreased quickly, whereas soluble protein content decreased gradually. The content was much higher with the addition of sprayed spermidine than with only a single Cd^2＋ treatment, and the trend of decrease was lower. Under single Cd^2＋ stress, the maximal SOD, CAT and POD content appeared at 1, 1 and 2 mg· L^-1 Cd^2＋, respectively, and decreased gradually thereafter; the activities of these protective enzymes were markedly increased under spermidine treatment, by 5.8%, 37.5%, and 3.3%, respectively, and therefore decreased the generation rate of reactive oxygen species such as O2^- and MDA content.

关 键 词：CD^2+ 荇某 亚精胺 

分 类 号：X173[环境科学与工程—环境科学]