Color is the core indicator of the appearance quality of the fruit, which has an important impact on the commodity value of the fruit and its processed products.
In general, the most intuitive way to evaluate the quality of a variety is to see whether it shows a typical color, and varieties with excellent color tend to be more attractive to the market.
Therefore, whether the fruit is good or not is often a common concern of farmers in production, and this time we will talk about it.
<h1>The mechanism of fruit color formation</h1>
Fruit color includes the base color and surface color of the fruit surface, fruit coloring usually refers to the development of surface color, it is mainly related to chlorophyll, phenolic pigments (mainly anthocyanins, flavonoids and flavonols) and carotenoid accumulation or decomposition.
Yellow or orange fruits: the highest contribution rate to typical color is carotenoids, such as citrus color change is that after entering the ripening stage, the decomposition rate of chlorophyll is accelerated, the synthesis rate is reduced, the peel green gradually fades, and the carotenoid synthesis of the peel increases.
Purple or red fruit: its color is closely related to the type, content and distribution of anthocyanin accumulation, and the synthesis time and quantity of anthocyanins play a decisive role in the period and depth of red fruit.
From the above, it is not difficult to see that most of the young fruits are green, the reason is that the proportion of chlorophyll in the exposed part (generally the peel) is relatively high at this time, and the accumulation of carotenoids or anthocyanins increases after entering the mature stage, which eventually leads to changes in color, so their smooth synthesis is the core element of fruit color transformation.
<h1>Factors influencing fruit color change</h1>
fruit
As we mentioned before, due to the difference in the typical color of the fruit, the pigment species affecting the yellow fruit are mainly carotenoids, while the pigment species affecting purple fruit or red fruit are mainly anthocyanins.
(1) Carotenoids
External factors: including light, temperature, moisture, etc., such as good light can promote the synthesis of carotenoids; low temperature conditions are conducive to the decomposition of peel chlorophyll, the emergence of carotenoids; moderate water stress can promote the accumulation of fruit sugar, and accelerate the transformation of chlorophyll to colored bodies.
Intrinsic factors: the greater influence is sugar, endogenous hormones, mineral elements, etc., such as sufficient sugar can promote the production of carotenoids; when the level of ethylene and abscisic acid is high, it can promote the synthesis of carotenoids in advance; the high level of nitrogen in mineral elements is not conducive to chlorophyll decomposition, while potassium, phosphorus, calcium, magnesium, boron, zinc, molybdenum and other anabolic effects on the anabolic metabolism of carotenoids.
(2) Anthocyanins
External factors: mainly light, temperature, etc. Light is crucial to the synthesis of anthocyanins, and plays a role as a signal source in its synthesis, such as slow coloring of the fruit of the bagging, less anthocyanin accumulation, but the anthocyanin content can rise rapidly after bagging; temperature affects the synthesis mechanism of anthocyanins on the one hand at the level of gene transcription, on the other hand, by affecting the activity of enzymes in the anthocyanin synthesis pathway and the structural stability of the synthetic products. In general, when the temperature difference between day and night is large, it is conducive to its synthesis.
Intrinsic factors: sugars, organic acids, endogenous hormones, mineral elements, etc. For example, sugar can be used as a metabolic energy substance to provide energy for plant growth and development, it can be seen from the structure of anthocyanins that sugars are components of the anthocyanin structure, in addition, sugars are also signaling molecules, activating or inhibiting the expression of related genes; the composition and content of organic acids affect the hydrogen ion pH of cell fluid and vacuoles, while anthocyanins are located in the vacuoles of cells, and their stability is affected by the content of organic acids; the influence of endogenous hormones and mineral elements on the synthesis of anthocyanins is more similar to that of carotenoids. I will not repeat it here.
<h1>How to promote fruit discoloration? </h1>
After talking so much, in fact, we finally have to settle down on how to help the fruit change color. Although the above content is more theoretical, it corresponds to the production of color promotion measures, which is slightly refined here.
Environmental regulation: facility cultivation in the control of temperature and humidity, moderate water control at the maturity stage, improve light conditions such as pruning, de-occlusion, laying reflective mulch film, etc.
Reasonable fertilization: after the start of color change, nitrogen is controlled to increase the application of phosphorus and potassium and medium trace elements, and phosphorus and potassium foliar fertilizer can be sprayed, which promotes color change and is also conducive to the accumulation of sugar.
Leaf protection: sugar is a product of photosynthesis, can be used as a component of the structure of anthocyanins, while at a high level can promote the decomposition of chlorophyll and the synthesis of pigments, so protect the functional leaves, improve photosynthetic efficiency, greatly beneficial to fruit color change; roots are the basis of fertilizer water absorption and the synthesis of endogenous hormones, when the root system is weak, the upper part of the plant aboveground will be affected, so appropriate supplementation of humic acid biostimulants can be conducive to root repair and strength.
Use regulators with caution: Although hormones such as ethylene and abscisic acid can promote fruit color, attention should be paid to ways and methods, because the functions of hormones are often diverse, such as these two at the same time have the effect of accelerating aging and promoting the production of dissociation, and abuse may aggravate the later fruit fall.
This article is written and sorted by the agricultural assistant team, please be sure to indicate the source of the agricultural assistant, and do not modify the content of the article, the modification must be investigated!