答：楊凌老科協咨詢專家、西北農林科技大學研究員郝引川回復稱，玉米開花授粉的適宜溫度(du)為24℃—26℃，溫度(du)越高，花粉活力受影響(xiang)越大。今年的嚴重高溫干旱是造成花粒現象的根本(ben)原(yuan)因(yin)。

　　不(bu)過(guo)，不(bu)同(tong)(tong)播期、不(bu)同(tong)(tong)灌(guan)水(shui)時間、不(bu)同(tong)(tong)品(pin)種(zhong)(zhong)的表現存在(zai)明顯差異，具體(ti)來看(kan)：同(tong)(tong)一品(pin)種(zhong)(zhong)在(zai)同(tong)(tong)一地(di)方種(zhong)(zhong)植，若散(san)粉期恰逢連續高(gao)溫（尤其上午(wu)9—10點），花(hua)粉會快速死亡，導(dao)致缺(que)粒(li)(li)嚴(yan)(yan)重；高(gao)溫干(gan)旱時，抽雄散(san)粉期及時澆(jiao)水(shui)，授粉效(xiao)果(guo)會更(geng)(geng)好，反之缺(que)粒(li)(li)及禿頂現象(xiang)會更(geng)(geng)嚴(yan)(yan)重；不(bu)同(tong)(tong)品(pin)種(zhong)(zhong)差異也較大(da)，花(hua)粉量大(da)、散(san)粉持續時間長、雌雄協調的品(pin)種(zhong)(zhong)，授粉效(xiao)果(guo)更(geng)(geng)佳，反之則易出現缺(que)粒(li)(li)或(huo)空稈。