Plant growth regulators are artificially synthesized (or natural) chemical substances extracted from microorganisms, which have chemical properties similar to those of plant hormones and can accurately regulate the growth and development process of plants.
1. Basic definition
Plant growth regulators (PGRs) refer to natural active substances that are artificially synthesized or extracted from microorganisms. Their chemical properties are similar to those of plant hormones and can bidirectionally regulate (promote or inhibit) the growth, development, reproduction and other physiological processes of plants at extremely low concentrations. Its core features include:
Artificial synthesis property: Different from endogenous hormones, it emphasizes the chemical synthesis or extraction process of human intervention;
Similarity of physiological effects: Simulate the functions of natural hormones, such as gibberellins promoting stem and leaf elongation, ethephon ripening fruits, etc.;
Micro-high efficiency: Usually ppm-level concentrations can be effective, and the action is highly targeted (such as flower and fruit preservation or inhibition of vigorous growth).
2. Difference from plant hormones
Source difference: Plant hormones are endogenous substances secreted by plants themselves (such as auxin and abscisic acid), while regulators are exogenously applied;
Regulation method: Regulators can achieve more controllable agronomic goals (such as breaking seed dormancy or delaying aging) by interfering with the synthesis, transportation or metabolism of endogenous hormones.
3. Main functional classification
According to the direction of action, it can be divided into:
Growth promoters (such as aminoethyl esters and brassinolide) - enhance photosynthesis and break apical dominance;
Growth inhibitors (such as paclobutrazol and chlormequat) - control leggy growth and improve stress resistance;
Maturation regulators (such as ethephon) - ripen or preserve fruits.
Summary: This concept covers both the chemical nature (artificially synthesized hormone analogues) and emphasizes the agronomic application value (stable yield, increased yield, quality improvement, etc.).
