吸胀期低温与水分条件对油菜种子萌发的耦合效应

Interactive effects on rapeseed germination at low temperature and moisture during seed imbibition

为了探讨晚播油菜适宜播种的田间温度和水分条件，以华杂62和华双5号品种为材料，在土壤和PEG溶液两种介质中研究了吸胀温度与水势对种子萌发的影响。结果表明，吸胀期温度和水分条件对油菜种子的萌发具有显著影响。在5～15℃范围内，种子萌发活力随吸胀期土壤温度的升高而提高。在10℃和15℃下吸胀，土壤相对含水量为58．6％、水势为-0．1MPa时较适宜于种子萌发；在5℃低温下吸胀，适当降低土壤水势有利于种子萌发。华杂62种子具有吸胀冷害现象，在低温和高水势下吸胀，种子萌发活性降低，吸水速度加快，种子浸泡液K^＋渗漏量升高，而Na^＋渗漏量和Na^＋／K^＋比值降低。华双5号种子则具有较强的抗吸胀冷害能力，表现为在低温下吸胀受水势的影响较小。

In order to detect the appropriate temperature and moisture in field for late - sowing oilseed rape, two varieties Huaza 62 and Huashuang 5 were used to study the effects of temperature and water potential on seed germination during seed imbibition in soil and PEG solution. Results showed that the temperature and soil moisture had significant impacts on rapeseed germination. Under 5℃ to 15℃, seed vigor increased with increasing tempera- ture. Under 10℃ and 15℃, the appropriate moisture for seed germination was 58.6% of soil relative water content and -0.1 MPa of water potential. An appropriate lower water potential in soil was conducive to seed germination under 5℃. Rapeseed showed imbibitional chilling injury under low temperature. Under low temperature and high water potential, Huaza 62 seed vigor decreased, water absorption rate and K^＋ concentration increased, but Na^＋ concentration and Na^＋/K^＋ ratio decreased in the seed soaking solution. On the contrary, Huashuang 5 seed had a greater tolerance to imbibitional chilling injury and was less affected by water potential when imbibed under lower temperature.