From the analysis of the physiology of falling flowers, we have initially realized the influence characteristics of various internal and external factors in the process of falling flowers. Therefore, the measures to control flowering can only play the same role by creating suitable environmental conditions to prolong flowering period or using some growth regulators to control it.
1. Suitable cultivation and management techniques
Flowering plants need sufficient light, trees are shaded, and poor lighting conditions not only reduce the amount of flower bud differentiation, but also accelerate flowering. Especially for woody plants, the flowers in the inner layer of the crown often fall off first.
Therefore, when planting seedlings, appropriate space should be left between plants, and sunny areas should be selected for planting. The branches in the crown are too dense, so they need to be pruned and pruned in time to create suitable lighting conditions and reduce falling flowers.
In order to avoid freezing injury, it is necessary to choose suitable cold-resistant varieties for some plants that are prone to freezing injury in flowering period to reduce the degree of cold injury. For example, for tree species with early spring flowering, try to choose late flowering varieties to avoid the harm of late frost; For varieties with flowering period in late autumn, varieties with early flowering period should be selected to avoid the harm of early frost. In addition, for those plants that bloom in late autumn, the supply of fertilizer and water should be stopped as early as possible in cultivation, so that the plant growth can be stopped early and the flowering period can be advanced accordingly, which can also alleviate the cold damage.
Plants need sufficient fertilizer and water supply at flowering stage, usually nitrogen, and flowers and fruits are often not easy to fall off. When there is insufficient nitrogen, too much rain, or drought, flowering can be accelerated. Because nitrogen and various mineral nutrients participate in the synthesis of various hormones.
In addition, the application of boric acid outside the roots at flowering stage can also prevent flowering, because boron can promote the germination and elongation of pollen tubes.
In the flowering period of plants, special attention should be paid to the prevention and control of pests and diseases to ensure the soundness of leaves and flowers, so that the flowering period can be carried out normally and premature death can be avoided.
2. Control the coordination between vegetative growth and flowering.
At flowering stage, although plants should be under the conditions of abundant sunshine, suitable temperature and good management of fertilizer and water, if the growth rate of plant vegetative body is too strong, a large number of new branches will sprout continuously at flowering stage, which will often accelerate flowering. This situation is particularly obvious in young trees and some adult trees. For this kind of plants, the growth of their branches and leaves should be properly controlled. For example, before or during flowering, reduce the supply of fertilizer and water as much as possible, and control it by combining pruning, coring and thinning some branches and leaves.
On the contrary, if there are too many flowering plants, slender trees and few branches and leaves, it will not only accelerate flowering, but also promote the senescence of trees or be susceptible to pests and diseases. For this kind of plants, it is necessary to strengthen the management of soil fertilizer and water to make the trees grow healthily, and combine pruning to remove excessive branches or flowers, so as to make the leaf/flower ratio in the crown appropriate, prevent the trees from aging prematurely and delaying flowering, and at the same time overcome the phenomenon of bearing fruit in different years.
In addition, during the flowering period, cutting off some withered flowers at any time and concentrating nutrition on the blooming flowers can also prolong the flowering period. It is very effective in some herbal flowers, such as snapdragon, zinnia, violet and marigold.
3. Application of hormones
Because of the existence of some hormones, some parts of plant organs will delaminate, causing shedding. At present, some synthetic growth regulators have been used to control the shedding of plant organs, especially in the aspects of rapid defoliation, thinning flowers and fruits, etc., which are very effective.
(1) delay and prevent falling flowers
Carpenter (1956) sprayed 6ppm of 2,4,5-trichlorophenoxyacetamide at the flowering stage of poinsettia, which reduced the shedding of buds and leaves. West (1950) et al. sprayed NAA with the concentration of 10ppm during the blooming period of Japanese cherry blossoms or other ornamental cherry blossoms, which can prolong the flowering period. After treatment, a certain variety can keep 35-80% more flowers for 3-7 days than untreated plants.
Someone sprayed Cornus officinalis with 4-CPA(4- chlorophenoxyacetic acid) of 10ppm, so that the petal-shaped flower buds were attached for 4-6 days longer than the untreated plants.
2M-4x (dimethyl -4-chlorophenoxyacetic acid), BNOA(β- naphthoxyacetic acid) and 4-CPA are widely used in the production of solanaceous vegetables to control flower drop.
The concentration of tomato to prevent flowering is BNOA 25-50 ppm, 2M-4x 15-20 ppm and 4-CPA 25-50 ppm. Among them, 4-CPA has the best effect of preventing falling flowers. The method can be spraying, smearing or dipping.
(2) flower protection and fruit protection
On some woody plants, in order to prevent premature flowering and fruit dropping, 50ppm GA3 is usually used on citrus. 5- 10 ppm NAA also has an effect on the protection of apple flowers and fruits.
(3) flower thinning
Excessive flowering of plants can accelerate flowering, and flowering and fruiting will occur. Some growth regulators can be used for thinning flowers and have been widely used in fruit tree production.
Peach trees can be interplanted with phosphocresol dinitrate, plastic, p-chlorophenoxyacetic acid, ethephon and naphthylacetic acid. Applying carbaryl and NAA to apples.
(4) Frost prevention in flowering period
Some growth regulators can be used to reduce frost damage. If pear trees are sprayed with 50ppm GA3 before flowering, the freezing injury of flowers can be reduced. Another example is some ornamental plants, such as citrus fruits, bergamot, citrus and so on. In order to prevent fruit falling in winter, young fruits can be treated with a certain concentration of GA.
Using higher concentration of auxin can inhibit growth, and auxin is usually used to inhibit the germination of lateral buds, so that plants can stop growing ahead of time before winter comes. In addition, chlormequat chloride can also be used, which has the same inhibitory effect.
In order to avoid the harm of late frost, the use of growth regulators can delay the flowering of plants in early spring. Here, the role of hormones is actually to extend the dormancy period.
Because some kinds of hormones are only suitable for certain plant species, they cannot be widely used. In addition, different plants need different concentrations. If used improperly, it will cause drug harm or adverse consequences.
4. Extend the life of flower arrangement
Since Laurie (1936) found that putting a copper wire in a vase with flower arrangement can prolong the flowering period of flower arrangement by 1-2.7 days, which is effective for the flowers of plants such as snapdragon, aster, violet and marigold. Since then, people have noticed the role of chemicals in prolonging the life of flower arrangement.
Effect of (1) chemicals on prolonging the life of flower arrangement
Hundreds of chemicals have been tried to prolong the life of flower arrangement, but as a result, most chemicals are ineffective.
At present, it is generally proved that the drugs used include preservatives, growth regulators and some sugar nutrition. The function of preservative is to inhibit the growth of microorganisms, so as to prevent the vascular bundle tissue at the lower end of the flower branch from being blocked by excrement and dirt. The role of hormones may be to delay the aging process. The function of sugar is to provide energy for maintaining the metabolism of flowers. Some chemicals are added to some formulas, which may improve water metabolism. After treatment, these drugs can prolong the life of flower arrangement by 4-6 days. (2) Using chemicals or some hormones can keep the flower arrangement fresh, thus prolonging its life. This method has practical significance in some factories. However, different plant species should adopt different drug formulations and different concentration ratios because of their differences in structure and genetic characteristics. Even the same drug and concentration will cause different reactions in similar plants.
Regarding the examples listed below, in order to prolong the life of flower arrangement, some plants or varieties that are not included should be carefully tested and not used blindly.
(1) Larsen (1966) It was proved by experiments that the flower branches of different varieties of snapdragon can prolong the life of flower arrangement by 2.7 times by putting them into the solution containing 300 ppm QC(8- hydroxyquinoline citrate), 10-50 ppm SADH and 1.5% sucrose.
Larsen believes that the main function of sucrose in the above solution is to solve the energy of metabolic process, and QC is mainly used to control the growth of microorganisms; SADH may reduce the water demand of flower arrangement, slow down the process of metabolic activity, and also control some microorganisms.
Larsen and Wittwer( 1966) marked the spikelets of snapdragon soaked in SADH with C 14. Less than 30 minutes later, the drug has spread to the whole peak, indicating that the passive transport speed of the drug through blood vessels is also very fast.
(2) ②Larsen et al. (1965) proved that putting some varieties of carnation in nutrient solution or in the mixed solution of 500ppm SADH, 3-5% sucrose and 300-500 ppm QC in nutrient solution and preserving at room temperature can double the flowering period.
They believe that in this solution, sucrose is the energy source to delay aging, QC can prevent vascular tissue from being blocked, and SADH can promote the transportation of water flow.
(3) ③Halery et al. (1966) Soaked the flower branches of 5 species of carnation and 4 species of snapdragon in CCC and SADH overnight, which could prolong the flower life by 2-3 days. CCC concentration is 50ppm in summer and 10-25 ppm in winter.
McLean (1962) can also delay senescence by treating chrysanthemum with the above methods. It was also found that the respiration rate of chrysanthemum stems decreased by 22.2%.
(4) Norwegian Hyde et al. (1969) found that soaking carnation branches in 10-3M BA solution for 2 minutes can prolong the life of flower arrangement by 3-5 days.
Another method is to treat the cuttlefish in the above solution, then put it in clean water or 5% sucrose solution with pH value of 3.5, and store the treated cuttlefish at 0.5℃ for 4 weeks. After these treatments, the flower branches can have the same life as the newly picked flowers.
The flower branches of narcissus can keep fresh when they are placed in the mixed solution of 5× 10-4 mbaa and 10-4 m2, 4-d.
It is estimated that the function of this mixture is to prevent dehydration and withering of flowers during senescence.
⑤Vota and Harris( 1964) sprayed plants with 25ppm or 50ppm BA solution 2 hours before picking flowers of a certain variety of lilac, then stored them at 10℃ for 5 days, then cut off their flower branches and stored them in water bottles for 3 days at 2 1℃. After such treatment, leaves and flowers can keep their original bright colors.
⑥Hardenbarg et al. (1970) put six carnation varieties into Cornell solution, which had the effect of prolonging the flowering period.
Cornell solution, including 5% sucrose, 200ppm 8- hydroxyquinoline sulfate and 50ppm silver acetate.
In addition, putting the flower branches of orchids in 350ppm aspirin solution or 250ppm potassium permanganate solution can prolong the flowering period by 3-5 days.
Shanghai Institute of Plant Physiology and Hangzhou University (Liu Yu, Shen Zhende, Jin Yimin, 1987) used preservatives to treat cut flowers, which prolonged the flower arrangement life of carnation and rose by 5-7 days.
There are many traditional measures to preserve the life of flower arrangement in China, and the results are good, such as:
Heat treatment method: put the ends of flower branches of herbal flowers in hot water at 80℃ for a few minutes and then take them out. Or burn the ends of some wooden flowers on a small fire, then soak them in alcohol solution for one minute, and then rinse them with clear water. Such as poinsettia, honeysuckle, chrysanthemum, Babylonia, peony, hydrangea, clove, radix aucklandiae and so on. You can extend your life by applying the above methods.
Branch-breaking method: For some plants with fragile flower branches, scissors should not be used to cut off the flower branches, so as to avoid the fracture of vascular bundle tissue due to excessive cutting. Usually break it carefully with your fingers to avoid the broken surface being too large, and the flowering period can be extended.
Terminal pressing method: some woody flowers, such as magnolia, hydrangea, clove, peony, wisteria, etc. , the lower end cut before inserting the vase can be crushed about 3cm long to expand the water absorption area. It can also prolong the life of flower arrangement.
Deep-water first aid: When the flowers, branches and leaves in the vase are found to be slightly wilted, the original cut at the end of the flower branch should be immediately cut off by 3-6 cm, and then the whole flower branch should be immersed in water, leaving only the flowers exposed on the water. After soaking in this cold water for 65,438+0-2 hours, the flowers will be fresh again.
It is also meaningful to prolong the life of potted flowers. Specific measures can also refer to the above methods to extend the life of open-field flowers.