- Jul 30, 2017 -
Plant growth regulators have been widely used in horticultural crop production. It is small in size, fast, high efficiency, less residual, with a broad development and application prospects, is China's modern agriculture one of the most potential areas.
By understanding the types of plant growth regulators, physiological effects and mechanism of action, we need to learn and master the commonly used plant growth regulator preparation methods and application areas for the horticultural production services.
(A) the concept of plant growth regulators
Plant growth regulators are chemical substances that are studied and produced by chemical synthesis and microbial fermentation, and have some similar physiological and biological effects to natural plant hormones. To facilitate the distinction, natural plant hormones known as plant endogenous hormones, plant growth regulator is called exogenous hormones. Both in the chemical structure can be the same, it may be very different, but its physiological and biological effects are basically the same. Some plant growth regulators are themselves plant hormones.
(B) the type of plant growth regulator
Currently recognized plant hormones are auxin, gibberellin, ethylene, cytokinin and abscisic acid five categories. Brassinolide, polyamines, salicylic acid and jasmonic acid are also hormone-like, so it is divided into nine categories. And the types of plant growth regulators only in the horticultural crops on the application of more than 40 kinds. Such as gibberellin, naphthylacetic acid, indole acetic acid, indole butyric acid, 2,4-D, anti-retinoid, 6-benzylaminopurine, kinetin, ethephon, brassin Ester growth inhibitors are abscisic acid, cyanine, triiodobenzoic acid, etc .; plant growth retardants are paclobutrazol, chlormequat, uniconazole Wait.
(C) the mechanism of action of plant growth regulators
1. Activation of gene expression, alteration of cell wall properties to make it loose to induce cell growth; induction of enzyme activity, promotion or inhibition of nucleic acid and protein formation; alteration of certain metabolic pathways, promotion or inhibition of cell division and elongation; induction of disease resistance gene expression.
2. Promote the formation of buds and adventitious roots; induce flower bud formation, promote fruit hypertrophy, promote callus differentiation; promote top edge, inhibit lateral bud growth.
3. Break the dormancy, promote germination; inhibit lateral growth, promote vertical growth, promote flower bud formation; induced one-piece strong.
4. Prevent stem growth; increase respiratory enzyme and cell wall decomposition enzyme activity; promote fruit ripening, falling leaves, fruit drop and aging; break dormancy, promote flower bud formation and hair root.
(D) the preparation of plant growth regulators
1. Preparation method
Different plant growth regulators require different solvents to dissolve, and most plant growth regulators are insoluble in water and soluble in organic solvents.
(5) Application of plant growth regulators in horticultural crops
1. Break seed dormancy, promote germination
Gibberellin can break the seeds of citrus, peach, grapes, sweet orange, hazel, papaya and so on. Ethylene treatment can break the dormancy of strawberry and apple seeds. Cucumber seeded with BR treatment can improve the germination rate; potato chips with 0.5-1mg of gibberellin solution soak 10-15min, the fishing of potato seeds into the 1000mg / L gibberellin aqueous solution soaking 24h, can improve the germination rate; Out of the dry, in the wet sand germination or 10-20mg / L of gibberellin liquid spray tubers can promote potato germination. Lettuce seeds with 100mg / L gibberellin solution soaking 2-4h can increase the germination rate.
2. Promote rooting
Grape cuttings with 50mg / L IBA soaking base 8h, or with 50-100ml / L NAA soaking base 8-12h, or 50-100mg / L ABT root powder 1 soaked base 2-3h can promote cuttings Rooting; α-NAA can promote tomato, eggplant, pepper, cucumber and other branches rooting, with 50mg / L α-NAA liquid immersion tomato base 10min; or 2000mg / L α-NAA liquid speed dip eggplant, Cucumber cutting base can promote rooting.
3. Improve fruit set to prevent fruit drop
In the apple, pear, hawthorn flowering began to spray 25-50mg / L GA, or peach shoots in the growth of 10-30cm spray 1000mg / L of paclobutrazol can increase the fruit set rate. Tomato, eggplant, pepper and watermelon spray at the flowering time of 20mg / L 2,4-D or 20-40mg / L of the anti-falling factors can improve fruit set, to prevent falling fruit.
4. Induce or promote female flower formation
Cucumber seedlings 1-3 leaf leaves of the leaves of 100-200mg / L of ethephon, or 1-3 leaf foliage spray 10mg / L α-NAA, or 3-4 leaf foliage spray 500mg / L IAA can induce or promote female flower formation; pumpkin 3-5 slices of true leaf stage spray 150-300mg / L of ethylene can induce female flower formation.
5. Induced unisexed, forming seedless fruit
In the hawthorn flower spray 50mg / L GA can induce sexual strength; grape before flowering with 200mg / L GA plus a small amount of berry powder dip dipped in buds, a week after dipping flowers can induce the formation of seedless fruit; in the tomato protection Production, in the flowering with 10mg / L 2,4-D dipped in flowers can greatly improve the seed setting rate, the formation of seedless fruit; also in the tomato flowering spray 50mg / LGA induced single-seeded.
6. Increase fruit, increase production, improve varieties
Apple spray flowering 20mg / L BA can increase the fruit weight; pear and peach in the young fruit enlargement period spray 50mg / L of the cucumber can promote fruit hypertrophy. (10mg / L, 4-5 leaf stage), triacontanol (0.5), carbohydrate and carrot at the seedling stage, (100-1500mg / L, fleshy root formation period) can promote the growth and fleshy root hypertrophy. Celery in the 2-3 leaf stage and the next two weeks spray 2 times 10mg / L of gibberellin, or the heart of the period, 10 days before harvest spray 0.01mg / L BR can promote growth, increase yield and improve quality.
7. Promote fruit ripening
Apple ripening 3-4 weeks before spraying 800-1000 times the ethephon or mature 2 weeks before spraying 1mg / L of BA can be ripened in the peach flowering 70-80 days after spraying 400 times the ethylene can ripen; Tomato fruit white ripening period and the coloring stage before spraying and spraying of ethephon 300-500 times, 1000mg / L and 3000mg / L can promote the coloring and early maturation, and postharvest ethephon or diene di Ripening effect.
8. Sparse flowers
Apple flowering 10-15 days after spraying 5-20mg / L NAA or 10-25 days after blooming flowers spray 600-1000mg / L of civeton or flowering after 14-20 days spray 25-150mg / L of 6 -BA can be sprayed fruit; pear flowering 1 week after spraying 1500mg / L of civeton or pear, peach flowering 1-2 weeks after spraying 20-40mg / L α-NAA can be thinning.
9. Inhibit the growth of stems and leaves and shoots, and promote flower bud differentiation
Kiwi in May spray 2000mg / L of paclobutrazol can control the growth of shoots, internode shortening; spring when the new shoots long 10-30cm when spraying 1000mg / L of paclobutrazol can control the new shoots long, improve the fruit set; soil application 500mg / L CCC can prevent tomato leggy; tomato 2-4 slices of true leaf spray 300mg / L CCC can prevent stems and leggy, 5-8 slices of true leaf spray 10-20mg / L of paclobutrazol can prevent miao long; When the seedling with 10-100mg / L CCC soaking, can prevent leggy, increase the number of knot and yield.
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