7份梯牧草种质材料的种子萌发期抗旱性综合评价

Comprehensive evaluation of drought resistance of 7 Phleum pratense forage germplasm materials during seed germination

摘要:

【目的】探究干旱胁迫对梯牧草种子萌发和幼苗生长的影响，筛选抗旱种质。【方法】本研究以 6 份野生梯牧草材料及 1 份引种材料为研究对象，采用 PEG 模拟干旱胁迫，设置 0%、5%、10%、 15%、20% 5 个处理梯度，测定发芽指标与生长指标，分析抗旱性指标差异，确定适宜抗旱性鉴定浓度， 筛选抗旱性种质。【结果】低浓度 PEG（5%）一定程度上促进梯牧草种子的根长、芽长、鲜重、活力指数， 高浓度 PEG（≥15%）抑制其发芽率、发芽势、发芽指数、根长、芽长、根芽比和活力指数；与芽长相比， 根长对干旱胁迫更加敏感；15%PEG 宜作为梯牧草抗旱性鉴定浓度；野生材料具有较好的抗旱潜力， 主成分分析及隶属函数综合评价结果一致表明 7 份材料抗旱性由强到弱依次为 MS＞TM-3＞TM5＞TM-6＞TM-1＞TM-2＞TM-4。【结论】一定程度的干旱胁迫可促进梯牧草种子萌发和幼苗生长，该研究可为梯牧草抗旱性评价及新品种培育提供参考及背景材料。

Abstract:

【Objective】 In order to explore the effects of drought stress on seed germination and seedling growth of Phleum pratense ，the drought‐resistant germplasm was screened.【Method】 In this study，6 wild Phleum pratense L. forage materials and 1 introduced species material were used as research objects. PEG was used to simulate drought stress，and 5 treatment gradients of 0%，5%，10%，15% and 20% were set. The germination indexes and growth indexes were determined，the differences of drought resistance indexes were analyzed，and the appropriate drought resistance identification concentration was determined and drought resistance germplasm was screened. 【Result】 The results showed that the low concentration of PEG（5%） could promote the root length，shoot length， seedling fresh weight and vigour index，while the high concentration of PEG（≥15%）would inhibit the germination rate，germination potential，germination index，root length，shoot length，rootshoot ratio and vigour index. And the root length of Phleum pratense L. was more sensitive than shoot length for drought stress. 15%PEG was suitable for identifying drought resistance. Wild materials had better drought resistance potential. The results of principal component analysis and membership function comprehensive evaluation showed that the drought resistance of the seven materials was MS ＞ TM-3 ＞ TM-5 ＞ TM-6 ＞ TM-1 ＞ TM-2 ＞ TM-4 from strong to weak. 【Conclusion】 The research revealed that a certain degree of drought stress could promote seed germination and seedling growth of Phleum pratense ，and could provide some reference for the screening of drought-tolerant germplasm and the breeding of new drought‐tolerant varieties of Phleum pratense .