Chitosan Oligosaccharide is composed of 2-10 glucosamine connected by β-1,4-glucosidic bonds. Its regulation of plant growth is different from traditional biological pesticides and chemical pesticides. It can not only improve plant growth adversity resistance (including disease resistance, cold resistance and drought resistance, etc.), can also promote the growth of crops and improve crop quality. The following is an overview of the application in agriculture from the aspects of its function, mechanism and method of use.
1. The role of Chitosan Oligosaccharide in agriculture
1. Promote plant growth.
This mainly includes promoting seed germination, promoting root growth, promoting stem leaves, fruit growth, accelerating plant growth, improving crop quality, and increasing production and income.
A. To promote seed germination
Oligochitosan can promote the seed germination of crops. After the ryegrass seeds were treated with oligochitosan, the germination index and vigor index increased by 32.64% and 60.47% respectively compared with the control. Its promoting effect is related to promoting the activity of α-amylase in seed endosperm.
B. Chitosan Oligosaccharide can promote root growth
After using chitosan oligosaccharides, the roots of the plants are developed, and the hair roots and fibrous roots increase. This is not only beneficial to the growth of the above-ground parts of plants, but also can improve the tolerance of crops to some short-term adverse environments such as drought, low temperature, and early frost. And it can also enhance the resistance to soil-borne diseases including nematodes.
C. Chitosan Oligosaccharide can promote the growth of stems, leaves and fruits
After using chitosan oligosaccharide, the photosynthesis of plants can be enhanced, and photosynthetic rate and efficiency can be improved. Therefore, plants generally show: strong stem nodes, hypertrophy of leaves, bright color, vigorous growth, and strong plants.
After using chitosan oligosaccharides, the fruit setting rate of solanaceous vegetables and fruit trees generally increases, and the single fruit increases in weight.
D. Accelerate plant growth and development, improve quality, increase production and income
Oligochitosan treatment can accelerate the process of plant growth and development. It also can promote early flowering and maturity of crops.
Chitooligosaccharides were used to treat cucumber plants. When the cucumber seedlings grew to 3 to 4 true leaves, sprayed once every other week, repeated three times. The growth of the treated plants was significantly better than the blank control, the fruit harvest period could be 3-5 days earlier than blank control. And the yield was also significantly higher than the control. Rapeseed yield increased by 4.33%-9.67% after treatment.
2. Disease prevention and disease resistance.
Mainly including induction of disease resistance, broad-spectrum antibacterial, antiviral.
3. Insecticidal effect. Can be used as insecticide and pesticide carrier.
Transfer bacteria or plant chitinase to plants such as tobacco, tomato, lettuce, soybean, potato and sugar beet to obtain transgenic plants that can express chitinase activity. Compared with wild-type plants, transgenic plants are not only resistant to fungi, but also have certain resistance to insects and nematodes. However, the insecticidal activity of chitosan oligosaccharides is not as good as chemical pesticides, so it is not suitable to be used directly as conventional insecticide. It can be used as a partial substitute for insecticides or as a synergist of insecticides.
At the same time, the research on the bonding of pesticide molecules to natural polymer polysaccharides has opened up a new way for the production of low-toxicity and high-efficiency pesticides. Oligochitosan is used as a pesticide carrier, and some acidic pesticides can be easily bonded to its amino groups. For example, dichlorophenoxyacetic acid, dichloromethoxybenzoic acid, and 2-methyl-4-chlorophenoxyacetic acid can all be adsorbed on chitosan oligosaccharide molecular chains through the equilibrium effect in aqueous solution.
4. Improve the soil.
There are a large number of insects on the grassland, including a variety of beetles. Their carapaces and wings are rich in chitin. The acetylation process produces chitooligosaccharides of different molecular weights. Using chitosan oligosaccharide as a soil improver is beneficial to the germination, emergence, rooting and growth of plant seeds. Oligochitosan can also promote the growth of actinomycetes in the soil, which is beneficial to absorb nitrogen in the air and convert it into nitrogen available to plants, increasing nutrients.
Utilizing the antibacterial ability of chitosan and the function of improving soil, chitosan can be combined with soluble protein (such as collagen) to synthesize liquid soil conditioner. This soil conditioner has proper stability and degradability, and after degradation, it becomes a high-quality organic fertilizer. And this improver can inhibit the growth and reproduction of pathogenic bacteria in soil, and can effectively improve the particle structure of the soil at the same time, so it is an ideal liquid soil improver.
Obviously, oligochitosan plays a very important role in lushness or degradation of the grassland. It is an important tool and means for insects and microorganisms to contribute to the grassland. It is an important link in the ecological balance of the grassland.
2. The role and characteristics of Chitosan Oligosaccharide in agriculture
1. Good environmental compatibility
low toxicity to non-target organisms, little impact, easy to decompose in the environment, no residual impact, and no adverse effects on the environment and ecological balance
2. Ultra-high efficiency
Very little dosage, 1 gram of powder/mu, use concentration of 5-50ppm
3. Good safety
It only has an inhibitory effect on target harmful organisms, and has a high degree of safety on non-target organisms
4. Avoid drug resistance
By activating plant systemic acquired resistance (SAR) response, unique mechanism
5. Chitosan Oligosaccharide has a wide range of functions
Promoting plant growth, broad-spectrum antibacterial
3. Mechanism of action of Chitosan Oligosaccharide in agricultural application
Oligochitosan can effectively prevent and control crop diseases, mainly through two ways. One is that oligochitosan can inhibit the growth of plant pathogenic bacteria and weaken the infection ability of pathogens. The second is that chitosan oligosaccharides bind to receptors on plant cells to stimulate the production of resistance signal molecules such as NO, H2O2, Ca2+, jasmonic acid, etc. After signal transduction, the expression of resistance genes is stimulated to produce resistance substances such as β-1.3 Glucanase, chitinase, phytoalexin, phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, catalase, superoxide dismutase, etc., so as to achieve the purpose of disease prevention and treatment.
The promotion of plant growth by chitosan oligosaccharides is mainly due to the induction of the synthesis of auxin IAA. The auxin signal is transmitted to the plant to regulate growth, activate the expression of various growth and development genes in plants, and synthesize biologically active substances that are beneficial to plant growth. plant growth and development.
4. How to use Chitosan Oligosaccharide in agriculture
1. Seed soaking.
The function is to promote the germination of seeds; realize the normal growth of crops; improve the self-defense of plants.
2. Perfusion.
The function is to prevent the damage of continuous planting; to promote the activation of soil actinomycetes and fermentation bacteria, thereby improving the fertilizer effect; to activate rhizosphere microorganisms, which is conducive to the growth of plants; to prevent plants from withering and freezing to death.
3. Foliar spraying.
The role is to improve the self-defense of plants; resist drought, pests and diseases.
Action time:
can be used from seedling stage, transplanting stage, initial flowering stage, young fruit stage to harvest
Concentration of action:
50ppm/L, spray on the liquid surface once every 15-20 days, spray 3-5 times in total.
