Cr^(6+)胁迫对槐叶苹叶片光合生理特征及超微结构的影响  

Photosynthetic Physiological Characteristics and Ultrastructure of Salvinia natans Leaves under Cr^(6+) Stress

作　　者：王红霞[1] 施国新[1] 徐勤松[1] 计汪栋[1] 杨海燕[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：《西北植物学报》2008年第11期2244-2250,共7页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金项目(211100B372);高等学校博士学科点专项科研基金项目(20050319005);江苏省教育厅自然科学基金资助项目(05KJB180067)

摘　　要：采用不同浓度Cr6+的10%Hoagland营养液,于人工培养箱进行Cr6+胁迫培养槐叶苹,第7天测定其叶片光合色素含量、叶绿素荧光参数、活性氧产生速率、膜脂过氧化产物的含量、抗氧化系统等的变化,并观察其细胞超微结构。结果显示:随着Cr6+处理浓度的增加,(1)总叶绿素(Chl)、叶绿素a(Chl a)、叶绿素b(Chl b)、叶绿素a/b(Chl a/Chl b)和荧光参数(Fv/Fm和Fv/F0)呈不同程度的下降趋势;超氧阴离子(O2-.)、丙二醛(MDA)和可溶性糖(SS)显著增加。(2)超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)先升高后降低;抗坏血酸(AsA)、谷胱甘肽(GSH)和游离脯氨酸(Pro)也呈先升后降趋势,且始终高于对照。(3)超微结构主要表现为:叶绿体膨大、解体,被膜断裂、消失;线粒体嵴突消失、空泡化;核膜断裂、消失,核仁分散、核质散出。研究表明,Cr6+胁迫破坏了槐叶苹正常生理生化活动,并对叶片超微结构造成不可逆损伤,从而对槐叶苹产生毒害。The toxic effects of different gradient concentrations of Cr^6＋ （0,1,5,10,15,20 mg/L） on photosynthetic pigment content, chlorophyll fluorescence parameters, accumulation of superoxide radical, lipid peroxidation content, antioxidant systems and ultrastructure of leaf cells of Salvinia natans were investigated. The results showed that with Cr^6＋ increase, （1） chlorophyll （Chl）, chlorophyll a （Chl a）, chlorophyll b （Chl b） ,chlorophyll a/b （Chl a/Chl b） ,Fv/Fm and Fv/Fo decreased. The generation rate of superoxide anion （O2） ,malondiadehyde （MDA） and soluble sugar （SS） contents increased markedly. （2）Uperoxide dismutase （SOD）,peroxidase （POD） and Catalase （CAT） activities had similar trend,which was increasing firstly and then decreasing. Ascorbic acid （AsA）,glutathione （GSH） and free proline （Pro） contents enhanced progressively and followed by a decline at higher dose. （3）Transmission electron microscope observation indicated that Cr^6＋ imposed injury action on ultrastructure of leaf cells,such as swelling and disaggregation of chloroplast,breakage and disappearance of chloroplast envelope, effacement and vacuolization of mitochondria,disruption and vanishing of nuclear membrane, condensation of chromatin in nucleus, dispersion of nucleolus and nucleoplasm flowing into cytoplasm. The conclusion could be reached that the detriment of plant was resulted from disorder of physiological and biochemical metabolism and destruction of ultrastructure of leaf cells.

关 键 词：槐叶苹 Cr^6+胁迫 荧光参数 抗氧化系统 超微结构 

分 类 号：Q945.78[生物学—植物学]