玉米种子发芽和幼苗生长对水分环境的敏感性

玉米种子发芽和幼苗生长对水分环境十分敏感，低活力种子比高活力种子更敏感，水分环境影响玉米种子吸收水分的速度。不同水分条件下玉米种子发芽速度有显著差异，胚根伸长最早的在吸水30h左右，种子发芽最迟的在吸水90h以后，且发芽率显著下降；胚根伸长时的种子含水量在30％－65％内变化，发芽3－7d的幼苗长度与发芽过程中胚的含水量呈显著正相关，芽的生长比根的生长对水分更敏感。玉米种子在水分过多的环境中发芽，蛋白酶活性显著升高，淀粉酶活性显著下降，酶活动平衡受到严重影响。

Sensitivity of Maize Seed Germination and Seedling Growth to Water Environment

Maize seed germination and seedling growth were very sensitive to water environment. Low vigor seeds are more sensitive than high vigor seeds. Water environment affects the water uptake and germination of maize seeds. When the seeds imbibed in different water environments, the radicle protrusion started as early as about 30 h and late at 90 h; the moisture contents of maize seeds around radicle protrusion varied between 30% ～ 65 %. When there was too much water, seed germination was very slow and germination percentage was significantly decreased. Oxygen concentration mainly affected seedling growth, but not radicle protrusion. Seedling length was significantly correlated with the water contents of embryos during germination. When there was too much water during seed germination, the protease activity was very high and the α-amylase activity was significantly lower,the balance of protease and α-amylase activities was disturbed.