What is PGR?
The full form of PGR is Plant Growth Regulators. These are natural or synthetic chemical substances that influence plant growth and development by regulating processes like germination, flowering, fruiting, and root growth. Common types of PGRs include auxins, gibberellins, cytokinins, ethylene, and abscisic acid.
PGRs play a crucial role in enhancing crop yield, improving stress tolerance, and controlling plant responses to environmental conditions. They are widely used in agriculture, horticulture, and plant tissue culture to optimize plant growth and productivity.
Characteristics of PGR
Plant Growth Regulators (PGRs) are chemical substances that control and modify plant growth processes. They can be natural (phytohormones) or synthetic, influencing various physiological activities like germination, flowering, and stress responses.
Regulate Growth and Development – PGRs control seed germination, root formation, stem elongation, and fruit ripening. Their effects vary based on concentration and plant type.
Can Be Growth-Promoting or Inhibiting – Some PGRs, like auxins and gibberellins, promote growth, while others, like abscisic acid, inhibit growth to manage stress conditions.
Work in Low Concentrations – PGRs are highly effective even in minute amounts, influencing various biochemical pathways without being directly involved in plant metabolism.
Influence Environmental Responses – They help plants adapt to environmental stresses like drought, salinity, and temperature changes by regulating water balance and other physiological activities.
The Five Groups of Plant Growth Regulators
Auxins – These are essential for cell elongation and differentiation, mainly found in shoot tips and young leaves. Auxins regulate apical dominance, root development, and fruit formation. One key function is stimulating root growth in cuttings and tissue culture.
Gibberellins – These hormones promote stem elongation, seed germination, and flowering. They help break seed dormancy and support fruit enlargement. One important function is inducing seed germination in dormant seeds.
Cytokinins – These regulate cell division, shoot growth, and delay leaf senescence. Found in actively growing tissues, they balance auxin effects. A key function is promoting cell division in plant tissue culture.
Abscisic Acid (ABA) – Known as the stress hormone, ABA helps plants survive drought by closing stomata and inhibiting unnecessary growth. Its main function is regulating water loss by controlling stomatal closure.
Ethylene – A gaseous hormone that influences fruit ripening, leaf abscission, and stress responses. It speeds up aging and plays a role in plant defense. One major function is promoting fruit ripening in climacteric fruits like bananas and tomatoes.
Differentiate between Plant Hormones and Plant Growth Regulators:
Conclusion:
Plant Growth Regulators (PGRs) play a vital role in controlling and enhancing plant growth, development, and stress responses. Whether natural or synthetic, they are widely used in agriculture and horticulture to improve crop yield, regulate flowering, and enhance plant adaptability. Their precise application helps in optimizing plant growth for better productivity and sustainability.
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