What is yellowing in plants? Which pigment is involved in its regulation?

Chloroplasts and yellowing.

The pattern of growth characteristics of plants that grow in the dark or in conditions of very low light intensity. Yellowing seedlings of typical dicots, with small but not stretched leaves, lack of chlorophyll, and appear pale yellow; The internodes of the stem are long, the mechanical organization is not developed, and the stem is weak and cannot stand upright; The end of the stem is curved in a "hook" shape. In dark or low-light conditions, the differentiation of plant tissues is inhibited, so it is tender and juicy.

In the cultivation of vegetables, using this characteristic, leeks, garlic and bean sprouts can be cultivated, and onions can also be cultivated by soil cultivation methods to improve economic value. In wheat cultivation, if the planting is too dense, the canopy between the plants is closed, and the light is weak, so that the plant stem is slender, the internodes are too long, and the mechanical organization is not developed, resulting in lodging and reduced yield. The growth characteristics of plants in the dark are also conducive to exposing the soil surface as soon as possible after seed germination.

After planting, trees grow for a period of time, and often do not grow vigorously and the leaves appear yellowing. If not properly maintained, the tree will gradually decline and even die. How to maintain it to avoid this phenomenon?

1. After planting, water the roots in time with rooting agent (happy forest rooting liquid, happy forest rooting powder) to promote new roots, so that the root system can recover quickly, and absorb comprehensive nutrients from the soil as soon as possible.

2. Prevent root diseases, such as rot disease, root cancer, rhizobia, underground pests, so that the root system can grow healthily. (Commonly used agents include Fushengling, Zhongwei Soil Disinfectant, Hit Lujian, Jihe, Oxazole, Pentachloronitrobenzene, etc.) ）

3. After the trees survive, follow the "thin fertilizer and diligent application", spray some foliar fertilizer through the method of root topdressing and foliar spray, and make up for the shortcomings of the lack of nutrients absorbed by the root system in time to supplement the nutrients required for tree growth. (Commonly used foliar nutrient spraying techniques are: Chunyu No. 1 + ferrous sulfate; Chunyu No. 1 + urea; Chunyu No. 1 + compound fertilizer; Chunyu No. 1 + potassium dihydrogen phosphate, etc.

4. Reasonable pruning, pruning diseased and insect branches, canopy closed branches and vigorous branches if necessary, so as to reduce nutrient loss, ventilation and light transmission, promote photosynthesis, and increase the synthesis of chlorophyll.

5. Reasonable irrigation and drainage.

6. Condition the soil and increase soil permeability.

7. Saline-alkali soil improvement.

8. Choose adaptable tree species and local tree species.

Yellowing is generally caused by iron deficiency. It is mainly found in plants planted on alkaline soils. Because the soil is alkaline, the iron element of the plant cannot be absorbed! Causes the production of chlorophyll.

Common plants such as: rhododendron, gardenia, camphor tree, etc.