不同环境因素对节节麦萌发的影响

节节麦Aegilops tauschii Coss.是麦田难治杂草,研究环境条件对节节麦发芽的影响对预测其适生区域及综合治理有重要意义。以采自陕西、山东和河南的3个节节麦种群为对象,通过室内和室外萌发试验研究了水势、pH、盐分和播种深度与节节麦萌发的关系。结果表明,3个节节麦种群在不同的环境条件下表现出相似的萌发及出苗特性,其萌发对水势敏感,发芽率随水势的下降而降低,当渗透势小于-1.0 MPa时,种子不萌发;节节麦萌发对pH要求不高,在pH 3～10条件下发芽率均超过70%;其萌发具有一定的耐盐性,盐浓度为0 mmol/L时,发芽率最高,盐浓度大于420 mmol/L时,节节麦不能萌发;节节麦出苗率随播种深度的增加而降低,播种在土壤表面时,出苗率最高,播种深度大于10 cm时,未发现节节麦出苗。3个节节麦种群发芽对上述不同环境因子的反应差异不显著。

Effects of different environmental factors on seed germination of Aegilops tauschii Coss.

Laboratory and greenhouse experiments were conducted to determine the effects of water potential and salinity stress, pH and planting depth on germination of three populations of Aegilops tauschii from Shanxi, Shandong and Henan provinces. Aegilops tauschii seeds were sensitive to high water potential, and its germination decreased with the reduction of water potential. Furthermore, the seed germination was completely inhibited at a osmotic potential of -1.0 Mpa. The seeds can germinate over a wide range of pH level. There was no significant differences in germination of Aegilops tauschii under the pH value ranged from 3 to 10, with germination rate over 70%. The seeds of A. tauschii were relatively tolerant to salt and failed to germinate when the concentration of NaCl was over 420 mmol/L. Maximum seedling emergence occurred when the seeds were placed on the surface of the soil and seedling emergence decreased when increasing the sowing depth. No seed emerged at the sowing depths of 10 cm or over 10 cm. There was no significant differences in seed germination among the three populations collected from different sites.