观赏草丽色画眉种子萌发特性研究

Seed Germination Characteristics of Ornamental Grass Eragrostis spectabilis (Poaceae)

丽色画眉(Eragrostis spectabilis)在中国作为一种观赏草引种栽培,但有研究报道丽色画眉具有潜在的杂草入侵风险。通常成功的外来杂草有很强的繁殖能力,而丽色画眉种子的萌发特性如何,目前尚无人研究。本文通过培养皿和盆栽实验研究温度、光照、水分、土层深度对丽色画眉种子萌发的影响。以发芽率和发芽指数为评价指标的结果显示,丽色画眉种子最适萌发温度为35℃。应用种子萌发温度模型得出种子萌发温度范围为17.7～43.2℃,其中最适萌发温度为39.2℃。光照有利于种子萌发,与连续黑暗相比连续光照显著提高种子发芽率。PEG6000模拟的水分胁迫对丽色画眉种子的萌发有显著的抑制作用,水势降低到-0.8Mpa时,种子已经不能完成萌发。0.5cm是种子萌发的理想深度,0～1cm的土层适宜色画眉种子的萌发,发芽率不低于60%,在土层1～4cm范围内,随着土层深度的增加其萌发率显著降低。

Eragrostis spectabilis is used as an ornamental grass in China, but some researches reported that it had high potential risk of becoming invasive. Usually successful exotic weeds had strong reproduction ability. But for now, germination characteristics of E. spectabilis seeds have not been reported. Effects of temperature, light, water stress and soil depth on E. spectabilis seeds germination were studied by petri dish and pot experiments. The results showed that using germination percentage and germination index as evaluated indicators, the optimum germination temperature of E. spectabilis was 35 ~C. According to the seed germination thermal model （T, ~C ）, the germination temperature range was between 17.7 ~C and 43.2 ~C, with the best temperature of 39.2 ~C. Light was favorable for seed germination, the germination percentage was relatively higher under continuous light condition than continuous dark condition. PEG6000-simulated water stress significantly inhibited the germination. When water potential de- creased to -0.8 Mpa, seeds could not germinate. The soil depth of 0.5 cm was ideal for germination and the germi- nation percentages from 0-1 cm were more than 60%. The germination percentage decreased significantly with the increase of soil depth between 1-4 cm.