Vernalisation is process which improves qualitative and quantitative flowering in plants by exposure to cold conditions. It has dual functions. It allows plants to attain full maturity. It also stimulates early flowering of plants by providing desired conditions.

A sigmoid curve is a characteristic of a living organism growing in a natural environment. It is typical for all cells, tissues and organs of a plant.

The growth of a pollen tube is measured in terms of its length, an increase in surface area denotes growth in a dorsiventral leaf. Growth is, refore, measured by a variety of parameters.

Richmond Lang effect is related to delay in senescence of mature parts of plants. It is linked to cytokinin hormone. GA and NAA also help in attaining precocious maturity. ABA promotes senescence in stressful conditions.

Flowering in plants depends upon period of exposure of light to plant. Plants are able to measure duration of sunlight received through leaves. A hypotical hormone Florigen is said to be responsible for flowering.

The cells of maturation zone, attain ir maximal size in terms of wall thickening and protoplasmic modifications. From this region, some of epidermal cells form very fine and delicate, thread-like structures called root hair.

Every plant organism has an optimum temperature range best suited for its growth. Any deviation from this range could be detrimental to survival of plant.

Leaves are site for perception of light/dark duration. Florigen is responsible for flowering. Shoot apices are modified to flowering apices prior to flowering. The hormone furr migrates to stem and roots.

Dedifferentiation leads to formation of cork cambium and interfascicular cambium. Dedifferentiation is phenomenon that leads to regaining lost capacity of cells or tissues of plants to divide under special conditions. Differentiation is division and growth of cells in order to attain maturity. Redifferentiation is maturation of dedifferentiated cells reby specializing for a particular function. Development includes all changes undergone by a living plant from seed emergence to death.

Gibberellic acid is hormone which can be function similar to vernalisation treatment. IAA initiates rooting in stem cuttings. ABA is functional in unfavorable conditions. Kinetin is responsible for formation of new leaves, lateral shoot growth and adventitious shoot formation.