Plant Growth Regulators for Greenhouse Crops
(book excerpts)Plant growth regulators (PGRs) are synthetic compounds that exhibit responses similar to those caused by natural hormones in plants. They are applied for specific purposes to bring about specific plant responses. PGRs can be used to increase or retard plant height, prolong or break dormancy, prolong flower and plant shelf-life, prevent leaf yellowing, abort flowers, or promote rooting, branching, and flowering. Most of the PGRs used in the greenhouse function as growth retardants. These PGRs reduce plant height by inhibiting the production of gibberellins, which are the hormones responsible for cell elongation. Their effect is primarily on stem, petiole, and peduncle elongation. Leaf expansion may be reduced, too, resulting in smaller, thicker leaves with a darker green color, leading to reduced water requirements due to lower transpiration rates. Optimal crop performance is best achieved with a program of sound cultural practices in a carefully controlled environment. Although there is much scientific information on using PGRs in the greenhouse, it is not an exact science. Achieving the best results with PGRs is a combination of art and science—science tempered with a lot of trial and error and a good understanding of plant growth and development.
Click on the following topics for more information on plant growth regulators greenhouse crops.
Topics Within This Chapter:
- Cultural Practices for Controlling Plant Growth
- Container Size
- Plant Density
- Irrigation Practices
- Fertilization
- Mechanical Conditioning
- Pinching
- Brushing
- Light Quantity, Quality, and Photoperiod
- Light Quantity
- Light Quality
- Photoperiod
- Temperature Manipulation
- Using Plant Growth Regulators
- Regulate Shoot Growth
- Enhance Lateral Branching
- Enhance Flowering
- Removal of Flowers
- Other PGR Used in Greenhouse Production
- Active Plant Growth Regulator Ingredients
- Ancymidol
- Benzyladenine
- Chlormequat Chloride
- Daminozide
- Dikegulac Sodium
- Ethephon
- Flurprimidol
- Gibberellins
- Paclobutrazol
- Uniconazole
- Benzyladenine/Gibberellin Combination
- Plant Growth Regulators: Factors Affecting Plant Response
- Plant Factors
- Plant Species and Cultivars
- Stage of Plant Growth
- Plant Vigor
- Plant Size
- Environmental Factors
- Temperature and Light
- Growing Media
- Water Quality and Amount
- Physical and Chemical Factors
- Residual Chemical Effect
- Application Rates
- Time of Application
- Dosage
- Chemical Uptake and Translocation
- Coverage
- Spray Droplet Size
- Application Methods for Plant Growth Regulators
- Sprays
- Application Rates
- Factors Influencing the Effectiveness of PGR Sprays
- Spray Equipment
- Soil-Active PGRs
- Drenches
- Application Methods
- Watering-In
- Sprenches
- Plug and Liner Dips
- Factors that Influence the Effectiveness of Liner Dips
- Bulb Soaks
