Plant growth regulators that can induce crop stress resistance mainly include brassinolide, sodium nitrophenolate, indolebutyric acid, naphthylacetic acid, S-baitin, and hypersensitivity Protein etc. After use, these products can induce the stress resistance potential of plants and achieve the purposes of drought resistance, cold resistance, disease resistance, etc. In addition, plant dwarfing agents such as chlormequat, paclobutrazol, uniconazole and clofendiuron also have certain effects on improving stress resistance.
Brassinolide can stimulate plant growth and improve stress resistance, and is widely used in field crops, vegetables and fruit trees. For example, during the seedling, flowering and heading stages of wheat, spraying brassinolide with an effective concentration of 0.02-0.05 mg/kg can improve wheat's stress resistance and increase yield. During the soybean seedling stage and early flowering stage, foliar spraying of brassinolide with an effective concentration of 0.02-0.04 mg/kg can improve stress resistance. Sodium nitrophenolate promotes the flow of cell protoplasm, improves cell vitality, accelerates plant growth and development, and enhances stress resistance. It can break dormancy, promote germination, prevent flower and fruit drop, and increase yield. For example, spraying sodium nitrophenolate at an effective concentration of 6 to 9 mg/kg during the tomato seedling stage, flower bud stage, and fruit setting stage can better improve stress resistance and reduce tomato fruit drop. Indole acetic acid can effectively promote and regulate the nutritional and reproductive growth of crops, and improve plant resistance to drought, cold, disease, and barrenness. The effective concentration of indole acetic acid is 10 to 15 mg/kg, and is used for corn, wheat, and rice; or 0.75~1 mg/kg, used for seed dressing of tomatoes, cucumbers and other crops, which can significantly improve stress resistance. Indolebutyric acid? Naphthalene acetic acid has the functions of stimulating plant cell activity, breaking seed dormancy, promoting cell division and expansion, promoting root differentiation, stimulating callus formation of adventitious roots, accelerating root development, etc. It can enhance the stress resistance of plants. S-baitin induces the expression of various stress resistance genes in plants, activates the stress resistance immune system in plants, improves plant growth quality, and effectively enhances plants' ability to resist stress. It has a certain effect on improving quality and increasing yield. It can be used to spray stems and leaves of rice, cotton, tomatoes, grapes and tobacco to improve stress resistance and increase yield. Hypersensitive proteins and oligosaccharides can also induce plants to acquire resistance, thereby regulating growth and improving disease resistance. Their application on tomatoes, peppers, tobacco and other crops can effectively improve plant disease resistance.