NO介导的Ca^(2+)信号对渗透胁迫下紫花苜蓿幼苗光合特征及抗性的影响  

Role of NO-mediated Ca^(2+) signaling in regulation of photosynthesis and resistance to osmotic stress in alfalfa seedlings

作　　者：赵颖[1] 弋钦 魏小红[1] 辛夏青 韩厅 岳凯 王方琳[1] ZHAO Ying;YI Qin;WEI Xiao-hong;XIN Xia-qing;HAN Ting;YUE Kai;WANG Fang-lin(College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, Chin)

机构地区：[1]甘肃农业大学生命科学技术学院,甘肃兰州730070

出　　处：《草业学报》2018年第5期130-140,共11页Acta Prataculturae Sinica

基　　金：国家自然基金项目(31560663);甘肃省自然基金项目(145RJZA196)资助

摘　　要：以紫花苜蓿幼苗为材料,用聚乙二醇(PEG-6000)作为渗透介质人工模拟干旱条件,外源喷施NO供体硝普钠(SNP)、钙信号试剂CaCl_2、NO抑制剂亚甲基蓝(MB)和Ca^(2+) 通道阻断剂LaCl3,对紫花苜蓿幼苗光合特征、抗氧化酶活性及过氧化物酶(POD)同工酶图谱进行研究,探讨了渗透胁迫下NO介导的Ca^(2+) 信号对紫花苜蓿幼苗光合作用及抗氧化能力的影响。结果表明:在渗透胁迫条件下,施加SNP、CaCl_2均能够有效缓解叶片叶绿素a、类胡萝卜素及总叶绿素含量降低,提高叶片净光合速率(Pn)、气孔导度(Gs)及气孔限制值(Ls),而对胞间CO2浓度(Ci)没有缓解作用。SNP、CaCl_2及SNP+CaCl_2处理提高了幼苗叶片中抗氧化酶活性和脯氨酸含量,降低了丙二醛(MDA)含量。其中共处理时效果最为显著,第4天SOD、POD、CAT活性较PEG处理升高了39.29%、30.41%和56.24%,脯氨酸含量增加了45.59%,MDA含量降低了45.59%。POD同工酶图谱在第4天时酶谱带数最多,POD活性最强,且SNP+CaCl_2共处理下出现新酶带。而添加外源NO的同时添加Ca^(2+) 通道阻断剂LaCl3,紫花苜蓿幼苗光合速率、抗氧化酶活性及脯氨酸含量均降低,丙二醛含量增加,添加Ca^(2+) 信号的同时施加NO抑制剂MB也具有相同的作用,说明Ca^(2+) 信号参与NO信号转导过程并相互作用共同调节渗透胁迫下紫花苜蓿幼苗的生理应答响应。The nitric oxide（NO）and Ca^（2＋） transduction pathways have been implicated in mediating stress response and tolerance in plants.However,little is known about the interaction between NO and Ca^（2＋） signals,in regulation of photosynthesis and antioxidant capacity of alfalfa seedlings under drought stress.This research aimed to explore the mechanism by which Ca^（2＋） signaling mediated by nitric oxide（NO）in Medicago sativa seedlings regulates photosynthesis and antioxidant enzyme activity under osmotic stress.Solutions with：（i）differing osmotic potentials obtained using poly ethylene-glycol-6000（PEG）;（ii）a nitric oxide donor sodium nitroprusside（SNP）;（iii）an exogenous Ca^（2＋） signaling donor,calcium chloride（CaCl_2）;（iv）an NO blocker（methylene blue,MB）;and（v）a Ca^（2＋） channel blocker（LaCl3）,were pre-sprayed onto the leaves of alfalfa seedlings in different combinations.The effect of the NO-mediated Ca^（2＋） signaling on the photosynthetic pigment content,gas exchange parameters,antioxidant enzyme activity,on the levels of malondialdehyde（MDA）and proline,and on the peroxidase（POD）isoenzyme electrophoresis atlas were studied in leaves of alfalfa under osmotic stress simulated by 15% PEG.Results show that the photo-physiological characteristics of alfalfa seedling were significantly affected by osmotic stress.NO and Ca^（2＋） application alleviated the decrease of chlorophyll a,carotenoid contents and the total chlorophyll contents,increased net photosynthetic rate（Pn）,stomatal conductance（Gs）and stomatal limited value（Ls）,but reduced intercellular CO_2 concentration（Ci）in alfalfa seedling leaves.Furthermore,compared to SNP or CaCl_2 treatment alone,SNP and CaCl_2 treatments applied together significantly increased the activities of SOD,POD,CAT and the content of proline by 39.29%,30.41%,56.24% and 45.59%,respectively,and decreased the content of MDA by 45.59%.The POD is ozymeprofile exhibited the greatest ba

关 键 词：一氧化氮 钙离子 紫花苜蓿 渗透胁迫 光合特性 抗氧化酶 

分 类 号：S541.9[农业科学—作物学]