五、分雌的两极分化 1.分蘗的生长速度与分蘗两极分化一株小麦的各分蘗出现时间不同,在大小和生长速度等方面存在着差异,这些差异有时加大,有时缩小。我们把返青(春小麦和南方的冬小麦为起身前后)到抽穗期间,一株小麦的较大分蘗和较小分蘗之间的差距逐渐加大,最后有一部分分蘗抽穗结实,有一部分分蘗不抽穗死亡的过程叫作分蘗的两极分化。各分蘗的所有叶片中,只有—1位叶和—2位叶(见图1注)的生长速度最快。所以这两片叶的生长速度可以代表整个分蘗的生长速度。如果—1叶生长速度放慢到一定程度以后,分蘗的现有叶片数目就会少于应有的数目。有时一1叶生长过慢或停止生长,长 Fifth, the polarization of the sub-female 1. Growth rate of tillers and tiller polarization A tiller of a wheat appears at different times, there are differences in size and growth rate, these differences sometimes increase, sometimes narrow. We rejuvenate (spring wheat and southern winter wheat up and down) to heading, the gap between the larger tiller and the smaller tiller of a wheat gradually increased, and finally some of the tillering and heading were strong, and some of the tillers were not heading out to death The process is called tillering polarization. Of all the tillers, only the -1 and -2 leaves (see Note 1) grew the fastest. Therefore, the growth rate of these two leaves can represent the growth rate of the whole tiller. If the -1 leaf growth rate slows down to a certain extent, the existing number of tillers will be less than the number of leaves. Sometimes a leaf grows too slow or stops growing, long