Causes of withered fresh flowers and its fresh-keeping packaging technology

In the narrow sense, fresh cut flowers are cut from stems and leaves of cut flowers and used to make ornamental flowers such as bouquets, blue flowers, rosettes, vases, corsages, etc. In a broad sense, Cut ornamental wild ornamental plants, such as flower branches, fruit branches, stems and leaves, etc., cut into bottles for water conservation or for making bouquets, flower blue, garlands, wall flowers, chest ornaments and other ornamental materials are called cut flowers. Fresh cut flowers are the most delicate and most resistant to storage and transportation in economic crops. Fresh cut flowers have to undergo post-harvest handling, processing, transportation, storage, shelf placement, sales, and many other aspects, and how to minimize the loss of cut flowers and maintain the vividness of fresh cut flowers in these processes and links. It is an important issue facing flower producers, operators and researchers. Therefore, in-depth study of the causes of senescence and wilting of fresh cut flowers and various preservation techniques, especially researching and searching for new technologies for preservation packaging suitable for the current level of economic and technological development in China, will improve the quality of fresh cut flowers in China and promote the flower industry in China. Development has a great promotion effect. l. The main reasons affecting the fresh-cut flowers withered 1. The internal factors of fresh cut flowers that are senescent and withered are the internal factors of fresh-cut flowers. This is caused by a series of physiological disorders caused by squid cutting off the mother. 1.1.1 Water balance According to the principle of plant physiology, the freshness of cut flowers can only be obtained when water absorption is greater than transpiration. After the cut flowers leave the mother, the nutrient sources (including water) are cut off, and the balance between the transpiration and water supply of the leaves (including the leaves and stems and leaves) is destroyed, and the cut flowers firstly wilts due to water loss. The main reason for the wilting of cut flowers is due to the clogging of the squid conduits which interfere with the transport of water. Therefore, to maintain the fullness and color of the flowers, the most important thing is to make the flowers fully absorb water and maintain a certain degree of turgor. 1.1.2 Respiratory Metabolism After fresh flowers are cut, the nutrients stored in stems and leaves are used for metabolism. The wilting of cut flowers is caused by the lack of respiratory matrix. The rate of failure depends on the storage of nutrients in the stem. The metabolism of senescent petals is characterized by increased respiration and accelerated hydrolysis of cellular components. During the aging process, the activity of peroxidase, ribozyme, and other hydrolases is enhanced in the petals during aging, and the levels of macromolecular substances such as proteins, nucleic acids, starch, and cell wall polysaccharides are reduced, and the stability of cell membranes is changed. Before the cut flowers reach decay, the respiration will suddenly rise sharply, then suddenly drop after reaching the peak, there will be a “climbing period”, and the flowers will eventually wither. 1.1.3 Ethylene production and harm effects Ethylene gas is a ripening hormone that plays a key regulatory role in the process of flower failure. Ethylene inhibits the breakdown and redistribution of sugars in senescent organs of flowers through physiological effects. Ethylene is mainly produced by senescent tissues. When the amount of ethylene production reaches a peak (or exogenous ethylene is used to treat cut flowers), the petal will show symptoms of aging, such as degeneration, withering and curling. All flowers have a certain degree of sensitivity to ethylene, except that the degree of damage and response dose (ie, ethylene concentration) varies with the species. 1.1.4 Injury of pathogens After squid cutting, tangents and peroxidases are released from the wounded cells of the incision due to the traumatic reaction of the incision. The tannins are easily oxidized, and the viscous calcium and magnesium salts of their oxides accumulate around the cut fiber bundles. The enzymatic action causes the decomposition products of the acid acid to cause blockage of the transporting tissue, and at the same time, a large number of microorganisms are contained in the cuts of flowering branches. It reproduces rapidly, when infiltrate enters the catheter and metabolites of microorganisms will block the catheter. After flowering, the incision is contaminated. Due to the invasion of pathogens, it is also easy to cause rot in the base of the shoots, and the catheter loses its water absorption function and causes the cut flower to wither. 1.1.5 Other Plant Hormones Affecting Ethylene is the main hormone that affects cut flower senescence, but it is not unique. Cut flower senescence is regulated by the interaction of various hormones. It is also related to the flower plant genes. Abscisic acid (ABH) promotes aging, while auxin has a dual effect of delaying and accelerating aging. It has different manifestations in different types of flowers. 1.2 The main external factors of senescence and wilting external factors of fresh cut flowers and wilting of fresh cut flowers are closely related to the environment and fresh-keeping treatment of post-harvest cut flowers, and the good, bad (excellent, bad) external factors also directly affect cut flowers. Aging delays and accelerates. 1.2.1 Influence of water quality Under normal circumstances, low pH water quality can improve the balance of water in the plant. When the pH of the water is equal to or less than 4, the cell proliferation can be inhibited, the activity of the enzyme can be reduced, and the clogging of the catheter can be reduced. Phenomenon, but also for some fresh cut flowers can play a role in extending life. Naturally uncontaminated water, such as clean mountain springs, rivers, rivers, lakes, and rainwater, is superior to tap water. Chloride ions contained in tap water are harmful to cut flowers and accelerate aging. The warm water contains less cold air and less surface stress. It is easy to be absorbed. Inserting the cut flowers into warm water of 30-40°C can also clear the air bubbles in the catheter and make the water delivery in the cut flowers smooth. The life span of some cut flowers is related to the salt content in water. Generally, the life span is shortened as the hardness of water increases. The low salt content and the appropriate sugar amount in water can extend the cut flower life. 1.2.2 Influence of Temperature The ambient temperature is high, the respiratory frequency of cut flowers is increased, metabolic activity is accelerated, and energy consumption is increased, thereby shortening the life of cut flowers. Cooling can delay the aging process of cut flowers. At the same time, it can also inhibit the production of large amounts of ethylene at low temperatures. In the 0.5°C environment, cut flowers will not be harmed by ethylene. Therefore, cut flowers should be formed as far as possible after the post-harvest cold chain, which has positive significance for the preservation of fresh cut flowers.