紫花苜蓿光合特性及抗氧化物质对冷适应的响应  

Photosynthetic characteristics and response of antioxidant to cold adaptation of alfalfa

作　　者：孙万斌[1] 马晖玲[1] 周青平 SUN Wan-bin;MA Hui-ling;ZHOU Qing-ping(College of Grassland Science,Gansu Agricultural University,Key Laboratory for Grassland Ecosystem,Ministry of Education,Grassland Engineering Laboratory of Gansu Province,Sino-U.S.Centers for Grazing Land Ecosystem Sustainability,Lanzhou 730070,China;Institute of Qinghai-Tibet Plateau,Southwest Minzu University,Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station,Engineering Laboratory of Sichuan Provincial Development and Reform Commission,Chengdu 610041,China)

机构地区：[1]甘肃农业大学草业学院,草业生态系统教育部重点实验室,甘肃省草业工程实验室,中-美草地畜牧业可持续发展研究中心,甘肃兰州7300700 [2]西南民族大学青藏高原研究院,四川若尔盖高寒湿地生态系统国家野外科学观测研究站,四川省发改委工程实验室,四川成都610041

出　　处：《草原与草坪》2024年第3期26-34,共9页Grassland and Turf

基　　金：国家重点专项(2017YFC0504806);国家牧草产业技术体系(CARS-34)。

摘　　要：【目的】探究紫花苜蓿在冷适应过程中光合特性指标和抗氧化物质含量的变化。【方法】将10个紫花苜蓿品种的4周龄幼苗进行4℃冷适应处理,分别在第0、7、14天测定其叶绿素含量、渗透压、相对电导率、光合特性指标、活性氧物质和抗氧化物质含量。【结果】在冷适应初期(0~7 d),细胞膜受到损伤,造成离子泄露,叶片相对电导率升高,但随着冷适应过程的持续(7~14 d),离子泄露量减少,相对电导率降低,植株的抗寒性初步形成;冷适应造成叶绿素a、b含量、净光合速率、PSⅡ实际光化学效率及PSⅡ最大光化学效率降低。【结论】紫花苜蓿幼苗在冷适应过程中,其渗透压、抗坏血酸、氧化型谷胱甘肽和还原型谷胱甘肽含量持续升高,幼苗通过提高细胞液的渗透压,增加细胞液浓度,增强细胞的渗透调节能力,同时增加抗氧化物质含量,提高其抗氧化能力,从而减缓了超氧阴离子自由基和过氧化氢含量的持续升高。【Objective】In order to study the changes of photosynthetic characteristics and the contents of antioxi-dant substances of alfalfa during cold adaptation.【Method】The 4-week-old seedlings of 10 alfalfa varieties were cold-adapted at 4℃,and their chlorophyll content,osmotic pressure,relative electric conductivity,photosynthetic characteristics,the contents of reactive oxygen species and antioxidant substances were measured on the 0 th,7 th,and 14th days,respectively.【Result】The results showed that in the early stage of cold adaptation(0~7 d),the cell membrane was damaged,resulting in ion leakage and increased the relative conductivity of leaves.As the cold adapta-tion process continues(7~14 d),the amount of ion leakage decreased,the relative conductivity decreased,and the cold resistance of alfalfa was initially formed.Cold adaptation decreased the contents of chlorophyll a and chlorophyll b,net photosynthetic rate,actual photochemical efficiency of PSⅡ,and maximum photochemical efficiency of PSⅡin alfalfa.【Conclusion】The contents of osmotic pressure,ascorbic acid,oxidized glutathione and reduced glutathione of alfalfa seedlings increased continuously during cold adaptation.The osmotic pressure and concentration of cell fluid were increased to enhance the osmotic regulation ability of cells.At the same time,the content of antioxidant sub-stances increased and the antioxidant capacity enhanced,which could reduce the content of superoxide anion free radi-cal and hydrogen peroxide.

关 键 词：紫花苜蓿 冷适应 相对电导率 光合特性 抗氧化物质 

分 类 号：S541.1[农业科学—作物学]