野生毛葡萄“花溪-4”试管苗对PEG胁迫的形态及生理响应

Response of wild Vitis quinquangularis"Huaxi-4" tube seedlings to PEG stress in morphology and physiology

【目的】研究毛葡萄"花溪-4"试管苗在聚乙二醇(PEG)胁迫下的形态和生理响应,为毛葡萄苗期抗旱性鉴定提供依据。【方法】以毛葡萄单株"花溪-4"试管苗为试材,通过在培养基中加入不同质量浓度(0,30,60,90g/L)PEG-6000模拟干旱胁迫,研究"花溪-4"外观形态、保护酶系统、过氧化氢(H2O2)和丙二醛(MDA)含量的变化。【结果】不同质量浓度PEG胁迫对"花溪-4"试管苗生长的抑制程度不同,其质量浓度越大、胁迫时间越长,旱害越严重,对"花溪-4"试管苗生长的抑制效果越明显。随着PEG质量浓度的升高和胁迫时间的延长,"花溪-4"叶片中的MDA和H2O2含量均逐渐上升,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性则呈先上升后下降的变化趋势,且各生理指标峰值的出现时间与PEG质量浓度的高低相关,其质量浓度越高,峰值出现越早。MDA和H2O2含量与旱害指数(DI)呈极显著正相关,POD与DI呈极显著负相关,而SOD、CAT与DI相关性不显著。【结论】PEG胁迫会诱导"花溪-4"试管苗叶片内的H2O2含量上升,膜脂过氧化加重,而POD在试管苗活性氧清除中起主要作用;随PEG胁迫程度的加剧和胁迫时间的延长,"花溪-4"试管苗生长所受到的抑制作用增强。

【Objective】 For the purpose of providing basis for drought resistance of wild Vitis quinquangularis seedlings,the response of the tube seedlings of wild Vitis quinquangularis in morphology and physiology was studied under different concentrations of polyethylene glycol（PEG-6000）.【Method】 Taking the tube seedlings of Vitis quinquangularis ＂Huaxi-4＂ as materials,the changes in morphology,the activities of protective enzymes and the contents of H2O2 and MDA were studied under drought stress by PEG.【Result】 Drought stress,induced by PEG,had different inhibition actions on the growth of grape plantlets in vitro.In the meanwhile,drought hazard and growth inhibition were raised remarkably by adding concentrations and stress time.Along with different concentrations and long-term PEG stress,the contents of MDA and H2O2 were gradually increased,while the protective enzymes activities of SOD,POD and CAT,in the rooting tube seedlings,ascended first and then descended;the occurrence of the peak of protect enzymes was earlier with increased concentrations of PEG.There was a significant positive correlation between the contents of MDA and H2O2 and the index of drought hazard,and a significant negative correlation between the protective enzymes activities of POD and the index of drought hazard,but an insignificant correlation between the activities of SOD and CAT and the index of drought hazard.【Conclusion】 Along with different concentrations and long-term PEG stress,drought stress enhanced the inhibition actions of the growth on the tube seedlings of ＂Huaxi-4＂,and could induce increase in the contents of H2O2 and promote the peroxide of membrane lipid as well as the contents of MDA,while the contents of H2O2 served a primary function for ROS-eliminating system.