摘要
呼吸作用是种子萌发的唯一能量来源。本研究以‘新牧4号’紫花苜蓿(Medicago sativa L.‘Xinmu No.4’)为试验材料,探究了甜菜碱对低温下苜蓿萌发种子呼吸电子传递的影响。结果表明:低温抑制苜蓿种子的发芽率,但没有终止种子萌发进程;延长萌发时间,最终种子的萌发率与20℃下无差异。外施15 mmol·L^(-1)甜菜碱提高了低温下种子发芽率、发芽势、发芽指数,缩短低温下种子全部萌发的时间从而促进种子萌发,且温度越低,促进作用越大。甜菜碱提高了低温下种子呼吸速率,产生ATP的细胞色素C氧化酶呼吸速率及其在总呼吸中的占比显著增加,保证了苜蓿种子萌发所需的能量。此外,甜菜碱增加了交替氧化酶呼吸速率,减少了活性氧的产生,并且提高了苜蓿种子内SOD,POD,CAT活性,从而减少了H_(2)O_(2)的积累,有效缓解低温下种子的氧化伤害,维持低温下苜蓿种子较高的萌发速度,缩短萌发时间。
Respiration is the only source of energy during seed germination.In this study,the effect of betaine on the respiratory electron transfer of alfalfa germinating seeds at low temperature was investigated using‘Xinmu No.4’alfalfa(Medicago sativa L.‘Xinmu No.4’)as experimental material.The results showed that low temperatures significantly inhibited the germination rate of alfalfa seeds,but did not terminate the seed germination process.Prolonging the time of germination under low temperature,the final alfalfa seeds could still achieve a high germination rate and did not differ from 20℃.The external application of 15 mmol·L^(-1) betaine significantly increased the germination rate,germination potential,and germination index of seeds at low temperatures,and shortened the time for all seeds to germinate at low temperatures,thus promoting seed germination.The promotion of betaine to alfalfa seed germination was increased with the decline in temperature.Betaine significantly increased the respiration rate of alfalfa seeds at low temperatures,in which the respiration rate of cytochrome coxidase(COX),which produces ATP,and the percentage of COX respiration in total respiration were significantly increased,which ensured the energy supply required for alfalfa seed germination.In addition,the external application of betaine increased the respiration rate of alternative oxidase(AOX),reduced the production of reactive oxygen species(ROS),and increased the activities of SOD,POD,and CAT in alfalfa seeds,thereby reducing the accumulation of H_(2)O_(2),effectively alleviating the oxidative damage to the seeds at low temperatures.By this,a higher germination rate of alfalfa seeds was maintained and the germination time was shortened by betaine during seed germination of alfalfa under low temperature.
作者
王婕
刘美君
赵尧尧
张政
卫丹丹
龚梁祝
胡轩铭
WANG Jie;LIU MEI-jun;ZHAO Yao-yao;ZHANG Zheng;WEI Dan-dan;GONG Liang-zhu;HU Xuan-ming(Pratacultural College of Xinjiang Agricultural University,Key Laboratory of Grassland Resources and Ecology of Ministry of Education in Western Arid Areas,Xinjiang Key Laboratory of Grassland Resources and Ecology,Urumqi,Xinjiang 830052,China;Xinzhou Normal University,Xinzhou,Shanxi Province 034000,China)
出处
《草地学报》
CAS
CSCD
北大核心
2024年第3期763-771,共9页
Acta Agrestia Sinica
基金
农业生物育种重大专项-新疆地区耐盐碱抗旱高产苜蓿新品种设计与培育(2022ZD0401104)
新疆维吾尔自治区自然科学基金项目(2022D01A185)
国家自然科学基金(32360346)资助。
关键词
紫花苜蓿
低温胁迫
甜菜碱
种子萌发
呼吸电子传递
Alfalfa
Low temperature stress
Betaine
Seed germination
Respiratory electron transfer