不同温度条件下水分和盐分胁迫对画眉草种子萌发的影响

Effects of water stress and salt stress on seed germi⁃ nation of Eragrostis pilosa under different temperature regimes

摘要:

以画眉草(Eragrostis pilosa)为试验材料，探究不同温度条件下(25、30、35、40 ℃)种子萌发对水分和盐分胁迫的响应，并利用水势模型比较不同温度条件下种子萌发所需的基础水势。结果表明： 除温度与盐分互作对画眉草种子萌发率无显著(P＞0. 05)影响外，温度、水分/盐分及两者互作均极显著(P＜0. 01)影响画眉草种子的萌发率和萌发速率；不同水分和盐分条件下，25 ℃抑制画眉草种子萌发，而 40 ℃虽能促进种子萌发，但却抑制其幼苗生长；画眉草种子萌发的基础水势值随温度升高呈先降低后升高的趋势，其中水分胁迫条件下，30 ℃时种子萌发的基础水势最低，为-0. 75 MPa；盐分胁迫条件下，35 ℃时种子萌发的基础水势最低，为-0. 78 MPa。表明适宜的高温能够降低画眉草种子萌发对水分的需求，更有利于其在干旱、盐碱地萌发和建植。

Abstract:

We quantified the effect of water stress and salt stress on seed germination of Eragrostis pilosa under different temperature regimes(25，30，35 and 40 ℃). The hydrotime model was used to compare the base water po‐ tential for seed germination under different temperature regimes. The results showed that：1)Besides the interaction of temperature and salt stress had no significant(P＞0. 05)effect on germination percentage，temperature，water stress/salt stress and their interaction all had significant(P＜0. 01)effects on germination percentage and rate；2) Seed germination was inhibited at 25 ℃，and promoted at 40 ℃；whereas 40 ℃inhibited seedling growth under differ‐ ent water stress/salt stress；3)As temperature increasing，the base water potential for seed germination decreased first and then increased. The lowest base water potential was obtained at 30 ℃ under -0. 75 MPa for water stress. Under -0. 78 MPa for salt stress，the lowest was obtained at 35 ℃. Our results indicated that suitable high tempera‐ ture could reduce the water potential requirement for seed germination of E. pilosa，that will be easier to establish in the arid and saline‐alkali land.