Boron is an essential element for plants. Boron is not a component of various organic substances in crops, but it can enhance some important physiological functions of crops. Boron supply is sufficient, plants grow luxuriantly, seeds are full, roots are good, and harvest is guaranteed; On the contrary, the supply of boron is insufficient, the plant growth is poor, and the quality and yield of products are reduced; When there is a serious lack of boron, there is even no harvest. Boric acid is easily soluble in water and can be used in various soils. The most widely used application method is topdressing outside the root. According to the boron demand characteristics of crops, a certain proportion of boric acid aqueous solution is sprayed on the leaves during the growth period when crops need more boron. Soil fertilization is to fully mix boric acid with an appropriate amount of fine soil, or with manure, compost and other farm manure, and apply it into the soil before planting crops as base fertilizer or seed fertilizer. When making seed fertilizer, the seeds shall not be in direct contact with the fertilizer to avoid local toxicity. Lack of boron in soil will make crops suffer from “rotten heart disease” or “only flowering but no fruit”. The boron content in standard soil is 8 × 106. The physiological function of boron in crops is very complex, which is called trace regulatory element. Once crops lack boron, it will cause abnormal physiological metabolism and show special pathological changes in morphology. Boron is involved in the components of crop cells. Lack of boron will make the formation of crop cells incomplete and reduce their vitality, resulting in poor development of pollen cells; Boron has a good effect on the formation and stability of plant chlorophyll, and can promote the synthesis of amino acids and proteins in plants; Boron can promote the transformation and movement of carbohydrates in plants, improve the viscosity of cell protoplasm, and enhance the ability of crops to resist drought, cold, heat and disease.
The effects of Boron on crop growth and development can be summarized as follows:
1.Cell elongation and tissue differentiation
There is an obvious interaction between auxin (indoleacetic acid) and boron. Boron inhibited indoleacetic acid oxidase activity in roots. Under the stimulation of indoleacetic acid, root elongation was normal. Indole acetic acid in green plants is formed only in vascular plants, and it participates in the differentiation of xylem ducts. Therefore, the general demand for boron is also limited to vascular plants. But boron weakens the woody part of plants. The division of stem cambium cells was strengthened and the cambium cells proliferated.
2. Enzyme metabolism and wood formation
The accumulation of phenolic compounds inhibited the activity of indoleacetic acid oxidase. Boron can complex with phenolic compounds to overcome the inhibitory effect of phenolic compounds on indoleacetic acid oxidase. In the process of lignin formation and xylem vessel differentiation, boron inhibited the activity of hydroxylase phenolic enzyme.
3. Carbohydrate transport and protein metabolism
The protein content of new leaves of boron deficient plants is low, which is limited to cytoplasm, while the protein content of chloroplast is not affected. Therefore, the chlorosis of boron deficient plants is not common. Boron can enhance crop photosynthesis and promote the formation of carbohydrates. When crop boron is insufficient, it will cause a large accumulation of carbohydrates such as sugar and starch in leaves, which can not be transported to seeds and other parts, thus affecting crop yield.
4. Root growth and development
Boron and alcohols, sugars and other compounds can form peroxides to improve the supply of oxygen to crop roots. Especially in the case of hypoxia, the application of boron fertilizer can promote the development of crop roots. Therefore, for root and tuber crops such as beet, potato and radish, the effect of boron fertilizer is better.
5.Crop stress resistance
Boron can enhance the drought resistance and disease resistance of crops. Boron has the function of controlling water in the crop, which can improve the viscosity of crop protoplasts such as sunflower and buckwheat and enhance the ability of colloidal bound water. The application of boron can promote the formation of vitamin C, and the increase of vitamin C can increase the stress resistance of crops.
Post time: Dec-03-2021