Abstract: The effects of PEG stress on leaf proline content,relative water content,MDA content,superoxide dismutase(SOD) activity,and electrolyte leakage rate of three Lolium perenne L.varieties were investigated under treatments with different PEG concentrations.The results show that variety Premier was most resistant to osmotic stress and had the highest leaf relative water content,the least electrolyte leakage rate,and less increasing rates of MDA content under PEG stress,while the resistance of variety Fairway was the weakest.The proline accumulation in leaves of three varieties obviously increased under the PEG stress and Premier had stronger ability to resist PEG stress with rapid increasing in leaf proline contents.Superoxide dismutase(SOD) activities in leaves of three varieties increased during the initial stress stage at 5% PEG concentration and decreased continuously under severer stress.In summary,PEG stress resulted in the decreases in leaf relative water content and SOD activity and increases in leaf cell membrane permeability,MDA content,and proline accumulation of three L.prenne varieties and there was difference in the changing extents of the corresponding indices among three varieties.

Key words: Lolium prenne L., PEG stress, Plasma membrane permeability, SOD activity, Proline

摘要： 利用不同浓度PEG-6000溶液对3个多年生黑麦草(Lolium perenne L.)品种进行不同程度的水分胁迫处理,研究不同浓度PEG处理对各品种叶内游离脯氨酸与丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性和外渗率等生理性状的影响.结果表明:PEG胁迫处理下品种首相叶片相对含水量均最高,叶片外渗率均最低且MDA含量增幅较小,对渗透胁迫的抗性最强,而品种球道的抗旱性最弱;渗透胁迫下各品种叶内游离脯氨酸累积量都明显增加且在渗透胁迫加重时,品种首相叶内脯氨酸含量急剧上升,对渗透胁迫具有较强抵御能力;5%PEG浓度胁迫初期,各品种叶片SOD活性均有所提高,胁迫加重时SOD活性则呈现不断下降趋势;PEG渗透胁迫导致3个多年生黑麦草品种叶片相对含水量下降、细胞膜透性增大、MDA含量增加、脯氨酸含量上升而SOD活性下降,且3个品种对应指标的变化幅度存在差异.

关键词: 多年生黑麦草, PEG胁迫, 质膜透性, SOD活性, 脯氨酸