PLANT GROWTH REGULATORS (PGRS)

 

PLANT GROWTH REGULATORS (PGRS)

Plant growth regulators (PGRs) are naturally occurring chemicals that govern several aspects of plant growth and development. They are sometimes referred to as phytohormones or plant hormones. They are essential to several activities, including the germination of seeds, the development of roots, blooming, ripening of fruit, and reactions to external stimuli. The following describes several important regulators of plant growth:

1. Auxins:

Ø Function: Promote fruit growth, apical dominance, root initiation, and cell elongation.

Ø Natural Sources: The main natural auxin is indole-3-acetic acid (IAA).

Ø Auxins from synthetic sources, such as naphthalene acetic acid (NAA) and indole-3-butyric acid (IBA), are extensively utilized in agriculture.

2. Gibberellins (GAs):

Ø Encourage blooming, seed germination, and stem elongation as its functions.

Ø Natural Sources: One frequent naturally occurring gibberellin is gibberellic acid (GA3).

Ø Application: For some crops, used to increase fruit size and stimulate blooming in long-day plants.

3. Cytokinins:

Ø Function: Initiate cell division, stimulate the creation of chloroplasts, postpone senescence (aging), and encourage the production of shoots.

Ø Natural Sources: Plants naturally contain zeatin, a cytokinin.

Ø Utilized in tissue culture methods to encourage the growth of new shoots.

4. Abscisic Acid (ABA):

Ø Function: Promotes stomatal closure during water stress, inhibits development, and causes seeds and buds to go dormant.

Ø Natural Sources: Created in reaction to environmental stressors like drought.

Ø Application: Used to manage stomatal aperture and seeds' dormancy.

5. Ethylene:

Ø Function: Encourages senescence, fruit ripening, and leaf abscission.

Ø Natural Sources: Generated in reaction to cues from the environment, such stress and the ripening of fruit.

Ø Application: Helps regulate fruit storage and accelerate the maturity of climacteric fruits (such as tomatoes and bananas).

6. Brassinosteroids:

Ø Function: Promote cell elongation and division, enhance stress tolerance, and promote xylem differentiation.

Ø Natural Sources: Naturally occurring in plants.

Ø Application: Used to improve crop yield and stress tolerance.

7. Jasmonates:

Ø Function: Regulate plant responses to biotic stress (e.g., insect attacks) and induce defense mechanisms.

Ø Natural Sources: Jasmonic acid is a key molecule in this group.

Ø Application: Used in agriculture for pest management and to induce plant defense responses.

 

In horticulture and agriculture, plant growth regulators are used to manage plant growth and development for a variety of goals, including increasing crop output, regulating plant responses to environmental stresses, encouraging blooming, and controlling fruit ripening. To obtain desired results without generating unexpected repercussions, careful consideration of concentration, time, and manner must be made while applying them.