Foolish seeding disease of rice was found to be caused by a fungal pathogen Gibberalla fujikori. It was reported in 1926 by Japanese scientist Eiichi Kurosawa after observing symptoms in uninfected seedlings of rice after treatment with sterile filtrates of fungus which resulted in discovery of Gibberellic acid (GA₃).

Cytokinins is used to induce morphogenesis in plant tissue culture. Auxin and cytokinin toger in varied amounts carry out root and shoot differentiation. Ethylene leads to early ripening. ABA acts as a stress hormone.

Redifferentiation leads to formation of secondary xylem and phloem. 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. Dedifferentiation is regaining lost capacity of cells or tissues of plants to divide under special conditions. Differentiation is division and growth of cells in order to mature.

Auxin is associated with different movement of plant stem including phototropic and geotropic movements. GA promotes early maturity of plants. ABA prevents death of plant in stressful conditions. Ethylene increases respiratory rate of plants.

Indole-3-acetic acid (IAA) is hormone responsible for apical dominance. ABA promotes abscission of older parts. GA delays senescence. Kinetin helps in removing apical dominance and aiding lateral growth.

The first step in process of plant growth is seed germination. The seed germinates when favourable conditions are available like presence of oxygen, water and certain enzymes. If se conditions are not available, n a seed may suspend its activities and will germinate only when se conditions become available.

Phase of maturation lies next to phase of elongation. This phase lies away from root apex and is formed last in growth of root of plant.

Growth at a cellular level is principally a consequence of increase in amount of protoplasm. Since an increase in protoplasm is difficult to measure directly, one generally measures some quantity which is more or less proportional to it.

Both durations of light and dark are equally important. The critical duration of periods is essential for proper functioning of phytochromes present in plant.

The measurement and comparison of total growth per unit time are called an absolute growth rate. The growth of given system per unit time expressed on a common basis is called a relative growth rate.