摘要
干旱是影响高寒地区牧草种植和生产力的主要环境胁迫之一,而植物激素脱落酸(abscisic acid,ABA)在调控植物生长发育及应对环境胁迫中具有重要作用。本研究对高寒牧草红豆草(Onobrychis viciifolia)种子进行不同浓度的ABA浸种处理,室内10%PEG模拟干旱胁迫,通过检测和分析红豆草种子萌发指标和早期幼苗生长生理特性,探究外源ABA浸种对干旱条件下红豆草种子萌发和早期幼苗生长发育的影响。结果表明,干旱胁迫显著抑制了红豆草种子发芽率、发芽势、发芽指数和活力指数,而相较于干旱处理组,干旱胁迫下低浓度ABA(5 mg·L^(−1)和10 mg·L^(−1))浸种预处理能提高这些萌发特性。此外,10 mg·L^(−1) ABA浸种能显著促进红豆草早期幼苗的主根长度和根冠比,提高干旱胁迫下幼苗超氧化物歧化酶、过氧化物酶和过氧化氢酶等抗氧化酶的活性及渗透调节物质脯氨酸的含量,并减轻干旱胁迫对细胞氧化损伤的程度。然而,较高浓度ABA(>20 mg·L^(−1))浸种则对干旱胁迫下红豆草种子萌发和幼苗生长没有明显的积极影响,甚至会轻微抑制萌发,这可能是由于过度刺激胁迫反应或毒性所致。本研究表明,适宜浓度的ABA浸种能够提高干旱胁迫下红豆草种子的萌发特性,且能有效减轻干旱对早期幼苗的氧化损伤程度,这一结果为干旱地区优质牧草种植推广奠定了理论基础。
Drought is one of the major environmental stresses affecting forage planting and productivity in the alpine areas.Abscisic acid(ABA),a plant hormone,plays a critical role in regulating plant growth,development,and responses to environmental stresses.In this study,seeds of the alpine forage species Onobrychis viciifolia were subjected to different concentrations of ABA soaking treatments and then exposed to drought stress simulated by 10%polyethylene glycol(PEG6000)in a controlled indoor environment.The germination indices and physiological characteristics of early seedlings were measured and analyzed to investigate the effects of exogenous ABA soaking on seed germination and early seedling growth under drought conditions.The results indicated that drought stress significantly inhibited the germination rate,germination potential,germination index,and vigor index of O.viciifolia seeds.Pretreatment with low-concentration ABA,particularly 5 mg·L^(−1) and 10 mg·L^(−1) significantly improved these germination parameters.Additionally,pre-soaking seeds with 10 mg·L^(−1) ABA significantly increased the primary root elongation and root-shoot ratio.The activity of antioxidant enzymes,such as superoxide dismutase,peroxidase,and catalase,was significantly increased in the 10 mg·L^(−1) ABA-treated group,indicating enhanced antioxidant defense mechanisms.The content of osmotic regulatory substances,including proline also increased,suggesting improved osmoregulation and cellular protection under drought stress.However,higher concentrations of ABA(>20 mg·L^(−1))did not show any significant positive effects on seed germination or early seedling growth under drought conditions.In some cases,higher concentrations of ABA even slightly inhibited germination,possibly due to overstimulation of stress responses or toxicity.In conclusion,appropriate concentrations of ABA soaking can enhance the germination characteristics of O.viciifolia seeds under drought stress and effectively mitigate oxidative damage to early seedlings.The results of this study provide a theoretical basis for promoting the production of high-quality forage grasses in arid regions.
作者
马晓兰
王文颖
周华坤
李文婧
李蛟
李阳
邱庆辉
殷恒霞
MA Xiaolan;WANG Wenying;ZHOU Huakun;LI Wenjing;LI Jiao;LI Yang;QIU Qinghui;YIN Hengxia(State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University,Xining 810016,China;College of Eco-Environmental Engineering,Qinghai University,Xining 810016,China;College of Life Science,Qinghai Normal University,Xining 810016,China;Northwest Institute of Plateau Biology,Chinese Academy of Sciences/Key Laboratory of Restoration Ecology of Cold Area in Qinghai Province,Xining 810008,China)
出处
《中国生态农业学报(中英文)》
CAS
CSCD
北大核心
2024年第11期1882-1890,共9页
Chinese Journal of Eco-Agriculture
基金
国家自然科学基金项目(32300269)
青海省科学技术厅应用基础研究项目(2022-ZJ-731)
青海大学生态环境工程学院研究生科技创新项目(2023-stxy-Y08)资助。
关键词
红豆草
干旱胁迫
脱落酸
种子萌发
幼苗生长
Onobrychis viciifolia
Drought stress
Abscisic acid
Seed germination
Seedling growth