多种环境因素对荠菜萌发和出苗的影响

Influence of Environmental Factors on Seed Germination and Seedling Emergence of Capsella bursa-pastoris

为研究不同环境因素对荠菜种子萌发和出苗的影响,在室内条件下,设计不同温度、光照、酸碱度、盐浓度、渗透压和埋藏深度进行荠菜萌发试验。试验结果表明,荠菜种子最适萌发温度为恒温20℃和变温20℃/15℃,并且随着温度的升高,初始萌发时间缩短;种子萌发对光强不敏感;在不同酸碱度处理下,中性(pH 7)发芽率最高,过酸或过碱条件下,种子发芽率急剧下降;种子萌发对盐浓度的敏感性不高,在120 mmol/L NaCl的条件下仍然可以萌发;种子对渗透势很敏感,当渗透势大于-0.9 MPa时,萌发完全被抑制;种子位于土壤表层时,出苗率会最高,但随着埋藏深度的增加出苗率逐渐减少,当埋藏深度超过1.2 cm时,出苗完全被抑制。

Laboratory seed germination experiments were conducted to determine the influence of variousenvironmental factors, including temperature, light, pH value, salt stress, osmotic stress, and depth of sowing,on seed germination and seedling emergence of Capsella bursa-pastoris. The optimum germination occurred atconstant temperature 20℃ and fluctuating temperature 20℃/15℃, and the onset of germination was shortenedas temperature increased. Alternate light and dark did not have any effect on the germination of Capsellabursa-pastoris seeds. The highest germination in Capsella bursa-pastoris was found under neutral conditions（pH 7） with different pH value treatments; germination decreased sharply under increasing acidity andalkalinity. Seed germination was tolerant to salinity： germination still occurred at 120 mmol/L Na Cl（21%）, butit was sensitive to osmotic potential and totally inhibited at osmotic potential 〉-0.9 MPa. Seedling emergencewas the highest when seeds were placed on the soil surface but declined with burial depth increasing, and nomore emergence was observed with burial depth more than 1.2 cm.