There are four points in the germination process of soybean seeds. The first point: mature seeds begin to germinate in the soil; The second point: the radicle of the seed breaks through the seed coat and grows down to become the root system; The third point: the cells of hypocotyl grow and elongate correspondingly, and the germ extends out of the soil to form branches and leaves; The fourth point: leaves leave the soil with germs, turn green after opening and carry out photosynthesis.

1, seedling stage:?

The radicle of soybean seeds first protrudes from the micropyle of the ovule, and when the radicle is elongated to the same length as the seed, it is called germination. Hypocotyl elongates, seed coat falls off, and cotyledons are exposed to the soil surface with the elongation of hypocotyl. When cotyledons unfold, they are called seedlings. Under suitable conditions, seedlings can emerge 4 ~ 6 days after sowing. More than half of cotyledons in the field were unearthed at seedling stage. ?

2. Seedling stage:?

The seedling stage of soybean is from emergence to flower bud differentiation. After emergence, the two leaves spread out, the young stem continues to elongate, and the upper two opposite single leaves spread out immediately, which is called the single leaf stage. With the elongation of young stems, the first compound leaf is called trilobal stage. In the third leaf stage, the growth rate of aboveground parts is slow, and the underground roots grow faster, forming nodules. At the end of this period, the root system was initially formed and needed more water and nutrients at first. The seedling stage is about 20 ~ 25 days, accounting for 1/5 of the whole growth period. This period is a long-rooted period, so we should pay attention to squatting seedlings, strengthen field management, achieve full, uniform and strong seedlings, and lay the foundation for high yield. ?

3. Flower bud differentiation period:?

The period from flower bud differentiation to flower bud differentiation of soybean is generally about 25 ~ 30 days. When there are 4 ~ 5 compound leaves, the lower part of the main stem begins to branch and differentiate flower buds at the same time. The process of flower bud differentiation begins with the appearance of hemispherical flower bud primordium, then an event sheet is formed in front of it, then a conduit is formed, and then a keel flap, a wing flap and a flag flap are differentiated. The ring stamen primordium differentiates one after another, the pistil in the center of the stamen begins to differentiate, and the ovule primordium appears, then the ovule and anther primordium differentiate, the flower organ grows gradually, and finally the flower bud, pollen and embryo sac are formed one after another, thus completing the flower bud differentiation. In the flower bud differentiation stage, plants enter the reproductive growth and vegetative growth stage. At this time, it is necessary to strengthen the management of fertilizer and water, and at the same time pay attention to coordinating vegetative growth and reproductive growth to meet the requirements of strong plants, many branches, many flower buds and healthy flowers.