How to use plant growth regulators
Plant growth regulator, a kind (class) of synthetic material, has regulating and control effects on plants, which can change the process of plant growth and flowering. Currently, growth regulators have been widely applied in flower cultivation, and have the following three categories:
a. Auxin class of growth regulators
Low concentrations of these chemicals can promote growth, while high concentrations will inhibit growth. It is widely applied in the promotion of rooting cuttings in asexual reproduction of flowers. Commonly used chemicals are indole butyric acid (IBA) and naphthalene acetic acid (NAA). There are two methods of application: one is using the solution. First, dissolved the IBA in a small amount of alcohol, then diluted with water and mixed into 5000ppm, and then diluted a concentration of required in further use. Another is using dry powder. Mix the IBA and talcum powder by 0.1% to 1% of the proportion, dip the base of the cuttings in such confections before cutting.
b. Gibberellin class of growth regulators
They play a role in promoting a variety of flowers for germination, growth and prevent fruit loss and so on. As GA soluble in water, it should be used with the distribution, otherwise prone to failure. Use 30ppm ~ 100ppm concentration of GA can make many kinds of annual and biannual flowers (such as snapdragon, calendula, etc.) and perennial flowers (such as chrysanthemum, peony, etc.) stem and leaf elongation. Experiments have shown that gibberellin can effectively break dormancy law of seeds, perennial and bulbous flowers, and promote germination. It also has a budding fast, vigorous foliage growth, early flowering and other effects on ornamental flowers.
c. Growth inhibition chemicals
This kind of chemical can control synthesis or metabolism of hormones in flower-plants, change the allocation of assimilates, regulating the growth of flowers, which can chunky flower stems, leaves dark green, thick leaves. As stem growth was inhibited, the competition for nutrient it had on bud germination would be reduced as well, thus making flowers bloom earlier. Commonly used inhibitors are Chlormequat and B9. The concentration range varies is depends on flower types. Chlormequat chloride or B9 not only can significantly reduce height of flowers, but also extend the life of fresh cutting flowers or a potted plant. For example, cut flowers carnation base with 50ppm (summer) or 10ppm ~ 25ppm (winter) of chlormequat, or 500ppm B9 soak a night, you can extend the flowering time of 2 to 3 days.
Light, water and fertilizer management must be strengthened after using regulators, otherwise, it is difficult to achieve the desired effects.