Everyone knows that humic acid is good for plants and can promote plant growth. But in addition to promoting plant growth and improving the soil, it also has the effect of improving the stress resistance of plants. Simply put, it allows plants to still grow normally in various harsh environments. Today we will talk in detail about the effect of humic acid on plant stress resistance.
1. Plant drought stress
Under drought conditions, the application of humic acid-containing fertilizers can promote the increase of proline content in plant leaves, promote the water-holding capacity of cells, and at the same time increase the activity of plant cell protection enzymes (nitrate reductase, superoxide dismutase, superoxide dismutase, oxidase, etc.), reduce cytoplasmic membrane permeability, etc. to comprehensively improve the drought resistance of crops.
2. Plant salt-alkali stress
Humic acid substances can indirectly improve the stress tolerance and resistance of plants by improving the physical and chemical properties of soil. In addition, humic acid can also regulate changes in fructose concentration to alleviate crop membrane damage under salt stress and enhance its salt resistance.
3. Plant temperature stress
Under low temperature stress, humic acid can increase the proline content and abscisic acid content of crops, enhance the activity of polyphenol oxidase, and attenuate the decrease in transpiration rate, stomatal conductance, and net photosynthetic rate of plants after low temperature stress. Cold resistance.
Humic acid also performs well under high temperature stress. The activities of crop superoxide dismutase and peroxidase are increased, which reduces the production rate of superoxide anions and the content of hydrogen peroxide, thereby enhancing the heat resistance of crops.
4. Plant heavy metal stress
Humic acid contains a variety of functional groups, which can fix heavy metals on the surface of soil particles through complexation, chelation, and reduction, thereby affecting their migration and reducing the water-soluble state of heavy metals, reducing their toxicity.
At the same time, humic acid can also alleviate the toxic effects of heavy metal cadmium on seedlings. The main mechanism is to inhibit its absorption of cadmium and promote its absorption and accumulation of nutrients such as copper, zinc, iron, and manganese.
5. Plant disease resistance
Humic acid can promote growth by increasing the sugar content and chlorophyll content of leaves, which indirectly improves the disease resistance of crops. At the same time, studies have shown that sodium humate can inhibit the germination of downy mildew sporangia, and its combination with other pesticides can significantly reduce the occurrence of downy mildew. At the same time, humic acid substances can also enhance the control effect against root-knot nematodes.
Phytic acid is widely used as a pesticide auxiliary due to its special structure and function. It has also been proven that humic acid has a good effect on plant disease resistance.
The above is an introduction to the stress resistance effect of humic acid on plants. I hope this can help everyone better understand humic acid.