Early germination of plants usually begins with the expiration of a period of dormancy. Dormancy period is the cessation of growth in plants due to environmental conditions that do not fit. The end of the dormancy period marked by the entry of water into the seed of a plant, called imbibition process.
The imbibition process will induce the activity of the enzyme (biokatalisator) that play a role in the metabolism) so early germination starts. When the leaves have formed, the plants are able to do photosynthesis. The process of photosynthesis to produce energy. Energy is used for growth and development.
Seeds can germinate because it constitutes a plant embryo or institution. Embryos or plant body has three parts, the roots of the institution / candidate root (radicle), leaves the institution (cotyledon), and the rod body (kaulikulus).
Roots organizations or radicle will grow and serve as root. Root end facing institutions burrow seed. At the time of seed germination, roots grow through the seed coat and out through the hole. In plants, grasses (Gramineae), the roots of the institution in the seeds root sheath enveloped by the institution (koleoriza).
Institution leaves or cotyledons are the first leaves of a plant. Leaves the institution has three functions, among others: (1) as a hoarder of food, which looks thick with a form generally convex on one side and flat on the other side, (2) as a tool to carry out photosynthesis, and (3) as a vacuum food for embryo (institution), which is a thin layer called the shield-shaped skutelum.
Trunk institution or kaulikulus divided into epikotil and hipokotil. Epikotil is on the leaf stem segments institution that will grow into stems and leaves. Hipokotil is under the leaf stem segments institution that will grow into akar.Kaulikulus along with the candidates leaves a part body called as sprout (plumula). Sprout has a cover called sheath sprout (koleoptilum).
Based on the location of germination, germination types can be grouped into two categories, namely epigeal germination and germination hipogeal.
Epigeal germination. Germination germination epigeal is marked by hipokotil raised to the ground. Cotyledons as energy reserves will make the process of division very quickly to form a leaf. This process can be seen in germination green beans (Phaseolus).
Hipogeal germination. Germination germination hipogeal is characterized by the formation would stem emerging from the ground, while the cotyledons remain in the soil. This process can be seen on the germination of peas (Pisum sativum)