二、根系的生长发育稻根既是支持器官,又是水份、养份的吸收和运输器官。根系的生长好坏对于水稻产量的高低有着特殊的作用。(一)根系的生育过程:水稻种子发芽时,胚根突破根鞘,形成种子根。永久根(冠根)长出后,种子根渐渐枯死,永久根发生于茎秆基部靠近地面的茎节上,在稻根的增根期中不断发生,形成一个须根系。秧苗初期茎 Second, the root system of growth and development Rice root is both supportive organs, but also water, nutrient absorption and transport organs. The growth of the root system is good for the level of rice yield has a special role. (A) the root of the fertility process: rice germination, radicle root sheath break through the formation of seed roots. After the permanent root (crown) grows, the seed root is gradually withering. The permanent root occurs at the stem node near the ground at the base of the stalk and continuously occurs during the rooting phase of the rice root, forming a fibrous root system. Stem early seedling