球形红细菌对镉胁迫下小麦幼苗几项生理生化指标的影响  

Effects of Rhodobacter sphaeroides on Some Physiological-Biochemical Indexes of Wheat Seedlings Under Cadmium Stress

作　　者：郭凌[1] 张肇铭[1] 芦冬涛[1] 

机构地区：[1]山西大学生命科学与技术学院,山西太原030006

出　　处：《农业环境科学学报》2008年第1期40-45,共6页Journal of Agro-Environment Science

基　　金：国家科技攻关项目(2001BA540C)

摘　　要：通过水培实验研究了0、0.5、5、10、20mg·L-1Cd2+和0、15%光合细菌球形红细菌(Rhodobacter sphaeroides)菌悬液复合处理对小麦幼苗叶片几项生理生化指标的影响。结果表明,在Cd2+胁迫下,小麦叶片丙二醛(malonyldialdehyde,MDA)和脯氨酸含量均随培养时间和处理液中Cd2+浓度的增加而增加,而小麦叶片中超氧化物歧化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)活性则随之降低。加入球形红细菌菌悬液后MDA和脯氨酸含量均有所降低,降幅分别为2.8%～20.5%和0.6%～15.2%;而SOD和CAT活性均有所升高,增幅分别为1.6%～59.4%和1.8%～12.4%。低浓度镉([Cd2+]=0.5mg·L-1)在幼苗培养第5d对叶绿素a、叶绿素b、类胡萝卜素和叶绿素总量的合成有一定的促进作用,但到第11d则转变为抑制作用。高浓度镉([Cd2+]>0.5mg·L-1)对4种光合色素的合成均有抑制作用,且抑制作用随培养时间和Cd2+浓度的增加而增加。加入球形红细菌菌悬液后小麦叶片4种光合色素含量都有不同程度的增加,增幅分别为1.4%～24.4%、0.7%～15.4%、2.4%～13.6%和1.2%～20.1%。这说明球形红细菌不仅可以增强Cd2+胁迫下小麦叶片抗氧化酶的活性,降低MDA和脯氨酸的含量,减轻体内膜脂过氧化的程度,而且可以增加光合色素的含量,从而缓解小麦受到的镉胁迫。The combined effects of Rhodobacter sphaeroides solutions （0,15%） and cadmium ion （0,0.5,5,10 and 20 mg· L^-1） on several physiological-biochemical indexes of the wheat seedlings leaves were investigated using water culture experiment. The results showed that under cadmium stress, the contents of malonyldialdehyde （MDA）and proline in leaves of wheat seedlings increased, but the activities of superoxide dismutase（SOD）and catalase（CAT）in the wheat seedling leaves decreased with the culture time and the cadmium concentrations increasing. Added Rhodobacter sphaeroides in solutions, the contents of MDA and proline in leaves of wheat seedlings decreased by 2.8%～20.5% and 0.6%～15.2%, and the activities of SOD and CAT increased by 1.6%～59.4% and 1.8%～12.4%, respectively. Low concentration of cadmium （0.5 mg·L^-1） promoted the compositions of chlorophyll a, chlorophyll b, carotenoid and total chlorophyll at 5th day, but inhibited them at 1 lth day. High concentrations of cadmium （〉0.5 mg·L^-1） inhibited the compositions of phytochrome, and this inhibition effect strengthened with the culture time and the cadmium concentrations increasing. The contents of phytochrome in leaves of wheat seedlings with Rhodobacter sphaeroide increased by 1.4%～24.4%, 0.7%～15.4%, 2.4%～13.6% and 1.2%～20.1%, respectively. The results suggested that Rhodobacter sphaeroides could enhance the activities of antioxidant enzyme, reduce the contents of MDA and proline, relieve the lipid peroxidation and increase the contents of phytochrome in wheat leaves under cadmium stress, thus mitigate the damage of cadmium intimidation to wheat seedlings.

关 键 词：球形红细菌 小麦 镉 丙二醛 脯氨酸 SOD CAT 叶绿素 

分 类 号：X172[环境科学与工程—环境科学]