Plants are developed from seeds. The embryo in the seed is the larva of a new plant, the radicle develops into a root, the embryo develops into a stem and a leaf, and the hypocotyl develops into a part connecting the root and the stem. Buds are divided into leaf buds, flower buds and mixed buds. Buds that develop into branches and leaves are called leaf buds, buds that develop into flowers are called flower buds, and buds that can develop into leaves and flowers are called mixed buds.
The structure that will develop into branches in the future is the branch bud. In the structure of branches and buds, the growing point can make the bud axis continuously elongate, the Ye Yuan base will develop into young leaves, the young leaves will develop into leaves, the bud axis will develop into stems, and the bud primordium will develop into lateral buds in the future. In fact, the branch bud is an undeveloped branch.
Four growth stages of plants:
1. Germination stage: Plants first grow vegetative organs such as roots, stems and leaves from seed germination.
2. Leaf development stage: after the radicle germinates, it first goes deep into the soil to form the main root, and then the hypocotyl elongates, pushing the cotyledons and germs out of the soil surface to form the leaves of plants.
3. Flowering period: After a certain period of vegetative growth, some parts of plants feel the changes of external conditions such as light and temperature, and flowers begin to form through the induction of some hormones.
4. Seed-setting stage: Through various pollination, pollen reaches the stigma of stamens, which stimulates the stigma to produce pollen tubes and carries the male ovule to ovule for fertilization. After fertilization, the egg cells begin to develop, and after a certain period of time, the ovule and various parts form fruits.