(a) IAA Indole acetic acid is the chemical name of auxin. It is synthesised at the growing apices of the plant, e.g., shoot tip, leaf primordia and developing seeds.

(b) Gibberellins It plays an important role in seed germination of plants and is synthesised in the apical shoot buds, young leaves, root tips and developing seeds.

(c) Cytokinins This plays an important role in actively dividing cells and are synthesised mainly in roots, but syntheses also occurs in endosperm of seeds growing embryo and seeds etc.

The apical buds present in tea and other plants prevents the growth of lateral buds in them, by releasing auxin hormone. This phenomenon is called apical dominance, Trimming of tea garden and botanical garden removes the apical bud and allowing the lateral buds to grow laterally and give plants a dense bushy appearance. The scientific explanation for this trimming method is that apical bud is removed thus results in the removal of auxin and phenomenon an of apical dominance is overcomed.

(i) Photosynthesis It is a totally light dependent process. Both quality and quantity affect the rate of the process resulting into total biomass accumulation by plants.

(ii) Transpiration It is loss of water by plant surface. Presence of light increases the temperature, thus affecting the rate of transpiration in plants.

(iii) Flowering The duration of light on plants effects the growth and development of plants, e.g., particularly flowering and this phenomenon is known as photo periodism. On the basis of photoperiodic response day flowering plants are categorised as long day, shert day and day neutral plants.

1. Lag phase-Growth is slow in this phase.

2. Exponential phase-shows rapid growth and maintains maximum growth for sometime.

3. Stationany phase-Growth diminishes and ultimately stops in this phase.

Growth is the main character which distinguish living organisms from non-living. All living organism grow in number and then accumulate biomass and grow in size as well. The growth is exhibited by all living organisms in terms of increase in number of cells as well as increase in size and length of each cell. In unicelluar organism, show growth and the growth is synchronous with reproduction. Unicellular organism when divide they produce offsprings (reproduction) i.e., each cell accumulate (synthesise) protoplasm and increase in size but up to a limit and divide to from two cells.