东北稻区杂草稻种子的越冬特性

Overwintering Characteristics of Weedy Rice Seed in Northeast China

东北稻区杂草稻经历了蔓延、大发生过程之后,近期进入衰弱态势,分布区域由过去大发生的东部稻区转移到降水量少的西部稻区。在东北稻区,稻田落粒的杂草稻种子只能以"干态"安全越冬,"湿态"种子不能安全越冬的主要原因在于其无休眠性;杂草稻种子安全越冬能力介于杂草类种子与栽培稻种子之间,其安全越冬能力强于栽培稻种子的原因在于种皮厚、吸水速率低、低温水中生存能力强、萌发后的种子耐旱性强,而脂肪酸、蛋白质含量差异不大。分析认为,杂草稻种子低温发芽能力强,秋季遇水易发芽而冬季冻死现象与其种子萌发期淀粉酶低温活性高于栽培稻种子相关。

After its spread and outbreak,weedy rice in Northeast China has recently entered a weakening situation. Its main distribution area has transferred from the previous eastern rice producing area to the western rice producing area. In Northeast China,weedy rice seeds can only overwinter in＂dry state＂,the main reason of which is that＂wet state＂seeds can not be safe in winter for its nondormancy; The ability of weedy rice to overwinter safely is between that of weed seeds and that of cultivated rice seeds,the main reason for the latter is that weedy rice seed coat is thick and its water absorption rate is lower,seed viability is strong in low temperature water,and drought resistance of the germinated seeds is strong; The difference of fatty acid and protein content between weedy rice seeds and cultivated rice seeds is not significant. The analysis shows that germination ability of weedy rice at low temperature is strong,its seeds are easy to germinate under water in autumn,and its winterkilling correlates with the fact that amylase activity is stronger than that of cultivated rice seeds in low temperature condition.