STEPS OF SEED GERMINATION IN INDIA

1. STEPS OF SEED GERMINATION Explanation of seed germination : Seed germination is the process by which a plant grows from a seed. The root is resulting in the break of the seed coat and emergence of the new young plant under the favorable condition of water, oxygen, temperature, and sometimes light. Botanically, germination may be defined as the emergence and development of the seed embryo of those essential structures that for the kind of seeds in questions are indicated to produce a normal plant under favourable condition. It is expressed in terms of percentage. Here let we knows steps of seed germination. Process of seed germination: The process of seed germination includes the following five changes or steps: imbibition, respiration, effect of light on seed germination, mobilization of reserves during seed germination, and role of growth regulators and development of the embryo axis into a seedling. The germination process is mainly divided into the following stages : 1 .Imbibition: Imbibition causes swelling of seeds and results in the breaking of testa. Imbibition is the initial step in seed germination. The water moves into ovules which are ripening into seeds by imbibition. Imbibition is dominant in the initial stage of water absorption by roots.

2. As seeds imbibe water, they expand and enzymes and food supplies become hydrated. Hydrated enzymes become active and the seed increase its metabolic activities to produce energy for the growth process. In addition, the water causes turgor pressure to increase in the cells and they are able to enlarge. 2. Respiration: Seeds require necessary energy to develop and grow, so germinating seeds undergo cellular respiration. Cellular respiration rates increase to accommodate the cell-building activities required to break open the seed and produce the initial root and stem structures. During aerobic respiration, seeds require oxygen as well as water and, in turn, produce carbon dioxide. Keeping seeds moist till germination will provide them with the required water content, which is necessary for the process of aerobic respiration and, in turn, causes the growth of the seed. 3. Effect of light on seed germination: Light is also an important signal for seed germination and seedling development. Many plants, such as lettuce, show photoblastic seed germination, requiring light exposure for germination.The size of a seed and its dispersal method both offer some clues as to its light preferences. Large seeds have a much larger endosperm, which means a young shoot has plenty of energy reserves to push through inches of soil and mulch before it can start photosynthesis. In contrast, small seeds have a small endosperm and need to immediately reach a light source for survival. In addition, seeds typically buried by animals may have adapted to prefer darkness when germinating. 4. Role of growth regulators: Plant growth regulators are the chemical substances which govern all the factors of development and growth within plants. Some other names used to refer to it are phytohormones and plant growth hormones.

3. Phytohormones are organic compounds which are either synthesized in laboratories or produced naturally within the plants. They profoundly control and modify the physiological processes like the growth, development, and movement of plants. Based on their actions, plant growth regulators are broadly classified into two major groups: Plant growth promoters Plant growth inhibitors. Auxins, Gibberellins, and Cytokinins are grouped into Plant growth promoters while Abscisic acid and Ethylene are grouped into Plant growth inhibitors. Ethylene can be grouped either into the promoters or into the plant inhibitors. 5. Development of the embryo axis into a seedling: The embryonic axis consists of three parts: the plumule, the radicle, and the hypocotyl. The portion of the embryo between the cotyledon attachment point and the radicle is known as the hypocotyl. The embryonic axis terminates in a radicle, which is the region from which the root will develop. Steps of seed germination is done according to the above mention points.