Plant growth and development started with fertilization process. After fertilization, ovule, which consists of triploid cells and zygote, continues to develop. Triploid cells divide and develop into tissues which are rich of nutrient termed endosperm.
|The Development of Dicotyledon embryo|
Embryo development in ovule starts as zygote divides into two Cells. cell division occurs repeatedly to form bail-shaped cell mass which then develops into embryo. Then, ovule develops into seed.
|Seed Structure (a) Dicotyl and (b) monocotyl|
A seed is able to germinate when the embryo within the seed is Still alive, not in condition of dormancy, and under suitable growing Condition. Embryo in the seed is composed of root embryo (radicle), leaft embryo (plumule), bud embryo (epicotyl), and stem embryo (hipocotyl).
The process of germination begins when seed absorbs water (imbibiton). Water drives seed coat to break and activate hormone And enzyme. Enzyme starts to break down nutrient in endosperm or cotyledon then conducts the nutrient to the growth point of embryo. Next radicle grows and breaks down the seed coat, anchors into soil develops into root. Meanwhile, hipocotyl grows upward to the soil surface, carries seed coat and cotyledon (for example, nut) or hipocotyl stays underground (for example, corn). Nut cotyledon and corn endosperm provide the first nutrient for young plant until the first leaft is able to conduct photosynthesis.
Types Of Germination
There are two types of plant germinations, epigeal and hypogeal. Germination is described as epigeal when cotyledon grows above the soil surface; usually, it occurs on dicotyledon.
Germination is described as hypogeal when cotyledon remains underground, which usually on monocotyledon