Abstract: In order to provide a theoretic guide to drought stress of manual manipulation and find the most drought tolerant variety for cultivation, nine orchardgrass (Dactylis glomerata L.) germplasms were used to demonstrate their drought tolerance according to seed germination response to drought stress. Three concentrations with 5%, 10%, and 13% of PEG-6000 were used as the penetration media to orchardgrass seeds in growth chambers. Drought tolerant index, plant vigor tolerant index, relative seed germination rate, relative seed germination vigor, relative embryo bud length (dry weight), and relative radical length (dry weight) of nine orchardgrass germplasm were measured to evaluate their drought tolerant abilities. Fussy subordinate function was used to assess drought tolerance. Correlation analysis was carried out to reveal the relationship between storage substances transporting rate and drought tolerance at seed germination stage. The average drought tolerance index of nine orchardgrass germplasm ranged from 0.139 to 0.935. ‘Baoxing' was the most drought tolerant material with 0.935 drought tolerant index, while ‘02-116' and ‘Sparta' were the second order with 0.883 and 0.824 drought tolerant indices. Samples of ‘01998' were least drought tolerant with drought tolerant index of 0.139. Relative embryo bud length and relative radical length were inhibited to some extent, storage substance transporting rate decreased also. Additionally, storage substance transporting rate was positively correlated with the drought tolerance of seed germination. The PEG-6000 of 13% was considered as the appropriate concentration to test orchardgrass drought tolerance at seed germination stage. Orchardgrass drought tolerance evaluation and storage substance transporting rate from fussy subordinate function were indicators of orchardgrass drought tolerance at seed germination stage.

Key words: Dactylis glomerata L., Osmotic stress, Seed germination, Drought tolerance, Subordinative function method

摘要： 根据不同鸭茅(Dactylis glomerata L.)品种萌发期对干旱胁迫的响应,评价9份南方主推鸭茅种质材料抗旱性差异,为其耐旱胁迫人工调控提供依据。PEG(PEG-6000)模拟干旱胁迫条件,分别以5%,10%和13%(-0.1 MPa,-0.2 MPa和-0.3 MPa)聚乙二醇溶液作渗透介质,采用人工气候箱内培养皿培养进行萌发期抗旱性研究,测定萌发抗旱指数、活力抗旱指数、相对发芽率、相对发芽势、相对胚芽长(干重)和相对胚根长(干重)6个指标,应用模糊隶属函数法进行耐旱性综合评价,并结合种子萌发期贮藏物质转运率与萌发抗旱指数相关性分析进行。结果表明:9个鸭茅材料耐旱隶属函数平均值范围为0.139~0.935。宝兴平均值最高,为0.935,其耐旱性最高,其次为02-116和斯巴达,平均值分别为0.883和0.824,而01998材料平均值最低,为0.139。胚根、胚芽在不同渗透胁迫条件下生长受到不同程度的抑制,贮藏物质转运效率降低,胚根、胚芽干重和贮藏物质与萌发抗旱指数相关性显著。13%PEG渗透溶液浓度胁迫处理8 d可作为研究鸭茅萌芽期抗旱性鉴定的水分胁迫适宜浓度。因此,采用模糊隶属法进行鸭茅耐旱性的综合评价时,贮藏物质转运效率可作为萌芽期抗旱性鉴定的重要指标。

关键词: 鸭茅, 渗透胁迫, 萌芽期, 抗旱性, 模糊隶属法