种子生长发育的动态研究表明,如果我们把一颗种子当作一棵植物看待,成熟的种子早已分化和具备了胚根、胚茎和胚叶,它应该是老年的植物体。种子真正的幼令期是从上一代的受精卵开始的,胚胎发育初期才是幼令期。对幼令植物体的低温锻炼,应该理解为对未成熟子的锻炼,而不是老年的成熟的种子。多年来,我们对玉米未成熟种子的研究证明,玉米授粉后仅15天,把还不到乳熟期(胚部第二片胚叶刚形成)的种子取下烘干,就有了发芽力。这时的种子很干瘪,千粒重不足20克,出苗率极低。对授 Dynamic studies of seed growth and development have shown that if we treat a seed as a plant, the mature seed is already well-differentiated and has the radicle, embryo stem and embryo, which should be the aged plant. The true young seed of a seed begins with the fertilized egg of the previous generation, and is young in early embryonic development. Cryogenic exercise of young plants should be understood as the exercise of immature seeds, rather than mature seeds of old age. Over the years, our research on maize immature seeds has shown that only 15 days after pollination of corn, the seeds that have not reached the milking stage (the second embryo of the embryo is formed) are removed and dried to have germination power . At this time the seeds are very dry, less than 20 grams of grain weight, very low emergence rate. To grant