温度胁迫对玉米种子萌发出苗的影响

[目的]以辽宁中西地区主栽玉米品种为研究对象,研究温度对玉米种子萌发至出苗的影响,为防寒减灾粮食生产安全提供科学依据。[方法]通过恒温土培法和分期播种试验,研究播种至出苗的生物学下限温度、有效积温指标和玉米适宜播种期及温度指标。[结果]玉米发芽率、发芽势随着温度升高呈非线性变化,规律性显著。16℃以下发芽率随温度变化迅速,而发芽势变化缓慢;16℃以上则相反。随着温度升高和播期推迟,播种至出苗生育进程加快,出苗天数随温度呈指数函数变化。供试验的玉米种子恒温6℃不萌发、8℃不出苗,恒温12℃与恒温26℃相比出苗延长24d;分期播种温度12.5℃与22.3℃相比出苗延长12d。低温播种影响出苗率,恒温土培8℃以下出苗率为0%,12℃出苗率为36%,分期播种Ⅰ期出苗率78%。[结论]玉米种子萌发下限温度为8℃,播种至出苗需要≥8℃的有效积温在120.0℃·d以上,玉米播种初始气温在12.0℃以上,辽宁中西部适宜播种期在4月下旬至5月上旬。研究结果可为玉米单粒播种苗全苗壮防寒减灾粮食生产安全提供技术支撑。

THE EFFECT OF TEMPERATURE STRESS ON THE CORN SEED GERMINATION AND EMERGENCE

In order to investigate the effect of temperature on main maize cultivars in Midwest Liaoning province. The indoor thermostatic culture and sowing date experiment were used to study the biological low temperature, effective accumulated temperature and the suitable sowing period of maize from sowing to emergence. The results showed that germination percentage and germination energy presented nonlinear trend with increasing temperature. Germination percentage was sensitive to the change of temperature when temperature remained below 16 degree centigrade. However, germination energy varied significantly when temperature was above 16 degree centigrade. It was found that the process of maize from sowing to emergence accelerated with the increasing temperature and lateness of sowing dates. The seed could not germinated when temperature remained 6 degree centigrade. Moreover, the seed could not emerged when temperature remained 8 degree centigrade. The period of emergence would be shorten 24 days by raising temperature from 12 degree centigrade to 26 degree centigrade. The experimental results also indicated that emergence rate of seed was easily affected by the low temperature. And the seed did not emerged basically that the temperature was below 8 degree centigrade. The percentage of emergence rate was 36% when temperature remained 12 degree centigrade. All the analysis shows that the biological low temperature of seed is 8 degree centigrade. And the effective accumulated temperature of seed from sowing to emergence are 120 degree centigrade for every day. The suitable sowing period in Midwest of Liaoning is from late April to early May. So these results can provide technical support for grain production safety.