The plant hormones are synthesised by the plant cells individually accordingly and when needed. Few hormones are specifically synthesised at a particular plant part, like auxin synthesised in growing shoot apices.

Ethylene is emitted by ripened fruits. Cytokinin is found in dividing cells. Unlike plants animal being more advanced, and organised they have proper hormone secreting glands and organs.

In both plant and animals these are transported through the transport system of their body. In plants, hormones are translocated via xylem and phloem to the site of activity.

Discovery of plant hormone gibberellins was made by chance. It happened by chance in rice fields. A few plants of rice were observed, which were unusually taller than the normal ones. Scientific investigation revealed, that these were infected with a fungus, known as Gibberella fufikuroi. This fungus releases a plant hormone gibberellic acid in excess concentrations which made the plant to grow unusually tall. This compound was later known as gibberellin is hormones present in all plants.

The term used for accidental finding is Serendipity which means fortunate happenstance. It was coined by Horace Walpole in 1754. He explained it as making discoveries, by accident and sagacity, of things, which were hot in quest of.

Regular mowing (cutting at apex) of lawn grass removes the apical portion of the plant which causes the lateral branches to grow faster. As the apical buds inhibits growth of lateral buds by releasing auxin, the phenomenon called apical dominance. Because of mowing of the grass, it becomes bushy and growth is faster. So, as to make evenness of the grass (carpet-like) in the lawn this practice is followed regularly to overcome the problem of apical dominance.

The meristematic cells can be identified of the basis of the following characteristics

(i) Cell have thin cellulose wall and dense cytoplasm with large nucleus.

(ii) Plasmodesmal connections are more numerous among meristematic cells.

(iii) Cell division, i.e., mitosis and its various stages are distinctly visible.

(iv) Chromosomes of cells replicate and divide into two homologous chromatids.

All these features contribute to open ended growth where structure is never complete in meristematic regions.

Whereas, cells incapable of divinding show features such as

(i) attains particular shape, size and thickening.

(ii) Undergoes structural and physiological differentiation.

(iii) Different types of cell are formed such as epidermis, cortex, vascular tissues.

Elasticity	Plasticity
The elasticity is stretchability of the plant cells or products, e.g., rubber/latex etc. The elastic substances can revert back to its original form in relaxed state. e.g., stretching of rubber.	Different pathways in response to environment or phases of life to form different kinds of structure is called plasticity. The plastic substances and phenomenon of plasticity are not reversible, i.e., irreversible. e.g., difference in shapes of leaves produced in air and those produced in water in buttercup. This is also known as heterophylly.