Improve Plant Stress Resistance
Dora Agri devoted to research and develop materials adding to specialty fertilizers to improve plant stress resistance.
During the process of growth and development, plants often experience various abiotic and biotic stresses, including drought, high temperature, low temperature, salinity, heavy metals, and pests and diseases. Plants growing under different environmental conditions can adopt different ways to resist various stress factors in the long-term evolution and adaptation process and form the ability to adapt to certain adversities. The ability of plants to resist various stress (adversity) factors is called stress resistance.
The stress encountered by plants can be divided into two categories, namely biotic stress (bacteria, fungi, viruses, insect pests, etc.) and abiotic stress (high salinity, drought, low temperature, low oxygen, etc.)
These factors have seriously restricted the development of sustainable agriculture. Many crops suffer from multiple stresses at the same time, causing serious losses to crop production. How to enhance plant stress resistance, repair and stabilize damaged and fragile ecosystems is a question worth exploring.
Cold Stress: Includes cold damage and freezing damage. Low-temperature injury refers to the damage to plants caused by low temperatures above 0 °C, mainly those plants originating from the tropics will be damaged at lower temperatures; Freezing injury refers to the damage caused by tissue freezing when plants are subjected to low-temperature stress.
Drought Stress: When the water loss of plant cells reaches a certain level, the arrangement of phospholipid molecules in the membrane is disordered, the membrane protein is destroyed, and the selective permeability of the membrane is lost;
The chloroplast and mitochondrial structures were also destroyed. Drought reduced the number of thylakoid sheets and distorted the number of chloroplast thylakoid lamellae, reduced the number of mitochondrial inner cristae, blurred the nucleus and nuclear membrane, condensed chromosomes, decreased the activity of synthetic enzymes, and decreased photosynthesis.
Salt Stress: Too much salt in the soil can cause salt damage to plants. In general, when the soil salinity exceeds 0.20% to 0.25%, it will cause salt stress.
The harmful effects of salt stress on plants are divided into two categories: one is the toxicity of salt ions to plants, including the damage to the plasma membrane and the interference to metabolism; The other type is two secondary toxic effects caused by salt ions, osmotic stress, and nutrient deficiency stress.
Plant Diseases: Refers to the infection of plants by various pathogens and the inhibition of plant growth and development.
The pectinesterase, pectinase, cutinase, and cellulase secreted by the pathogen hydrolyze the cell wall of the host plant, resulting in the rupture of the plant protoplast; the toxin produced by the pathogen destroys the structure of the host cell and interferes with the normal physiological activity of the host.
Specialty Materials Improve Stress Resistance
1. Marine Oligosaccharide
Marine oligosaccharide is obtained by degradation of marine polysaccharides, with unique molecular structure and biological activity. As an exogenous inducer, it has a certain regulatory effect on plant growth and defense response. It is a new and natural plant growth regulator.
Marine oligosaccharides are represented by chitosan oligosaccharides and alginate oligosaccharides. After plant cells recognize marine oligosaccharide signal molecules, they induce reactive oxygen species burst, cause signal molecule transduction, stimulate the expression of related defense genes, induce the activity of plant defense enzymes to increase, synthesize plant stress-resistant substances, and improve plant stress-resistant ability.
Chitosan oligosaccharide: it has the characteristics of good water solubility, easy absorption, and small molecular weight, and plays an important role in promoting plant growth and inducing plant stress resistance. Many studies have shown that chitosan oligosaccharide, as a plant stress inducer, can improve the defense ability of crops such as wheat, rape, cabbage, cucumber, and tobacco.
Chitosan oligosaccharide can also be used to control the disease control of fruits and vegetables after picking. Chitosan oligosaccharides can improve the resistance of plants to abiotic stress (such as drought, salt stress, etc.). (Cos Product)
Alginate Oligosaccharide: It’s a constituent of the cell wall of marine brown algae, accounting for 17% to 45% of the dry weight of algal cells. Alginate Oligosaccharide is a multifunctional oligosaccharide with a degree of polymerization of 2-20 obtained from the degradation of algin.
Like oligosaccharides from other sources, alginate oligosaccharides act as plant signaling molecules, participating in plant growth regulation and inducing stress resistance. (Alginate Oligosaccharide Product)
2. Arbuscular Mycorrhizae
Arbuscular mycorrhizae are the most widespread plant symbiotic fungi in nature and can improve host resistance to biotic and abiotic stress.
Mycorrhizae can improve nutrient absorption, increase the accumulation of osmotic regulation substances, increase the activity of antioxidant enzymes, strengthen osmotic regulation and maintain the balance of plant endogenous hormones. Increase auxin synthesis, regulate carbon and nitrogen metabolism and stimulate stress-induced gene expression. Enhance plant root system and the immobilization of mycelium itself on heavy metal elements to improve plant resistance to abiotic stress (drought, high and low temperature, heavy metals, salinity);
And through the construction of the mycelial network, it can form a mechanical barrier to the root invasion of pathogenic fungi, enhance the activity of disease resistance-related enzymes, synthesize secondary metabolites related to disease resistance, enhance the expression of disease resistance-related genes, and mycelial transmission defense. The signal can improve the resistance of adjacent plants and enhance the ability of plants to resist pests and diseases.
3. Glycine Betaine
Glycine Betaine has a variety of functions in resisting stress: osmotic regulation; scavenging reactive oxygen species; maintaining the stability of biofilms; protecting photosynthetic institutions; maintaining the structure and function of macromolecular protein complexes and some enzymes, etc. External application of betaine can effectively help plants resist abiotic stress because betaine increases photosynthesis efficiency and total soluble sugar content.
External application of betaine can effectively help plants resist cold stress and freezing stress. The reason was that betaine increased the photosynthetic efficiency and the content of total soluble sugar. No matter under low-temperature stress or during the subsequent normal temperature recovery, external application of betaine maintained a higher photosynthetic efficiency of plants.
Glycine Betaine can protect maize photosystem and improve CO2 assimilation under salt stress, thereby alleviating the damage caused by salt stress. Under salt stress, betaine significantly improved the photosynthetic capacity, stomatal conductance, transpiration rate, and the activities of related antioxidant enzymes in all plants to resist the salt stress environment. (Glycine Betaine Product)
After the brassinolide enters the plant, it not only strengthens the photosynthesis, promotes growth and development, but also has a protective effect on the membrane system of the plant cell, and can stimulate the activity of some protective enzymes in the plant, which can greatly reduce the damage to normal functions caused by harmful substances (such as malondialdehyde, etc.) produced by plants under stress.
A large number of experimental studies and field experiments have proved that brassinolide can indeed enhance the stress resistance of crops, especially in the aspects of drought resistance and low-temperature resistance, the effect is more obvious.
Under cold stress, Dora team treated the seeds and seedlings of pepper with brassinolide and found that after soaking the seeds with brassinolide, the germination rate, germination potential, vigor index, and germination index of seeds were significantly improved, and the levels of antioxidant enzymes and proline were up-regulated at the same time, reducing the content of MDA. (Brassinolide Product)
5. Salicylic Acid
Under various adversity stresses, the photosynthesis of plants showed a downward trend, and the supply of assimilation products decreased. Such as drought, cold damage, high temperature, salinity, waterlogging damage can reduce the activity of photosynthate, stomatal closure, resulting in insufficient supply of CO2 and reduce photosynthesis.
SA can increase the content of chlorophyll, increase the photosynthetic pigment, and improve the photosynthetic efficiency, thereby improving the stress resistance of plants. Salicylic Acid has a variety of important physiological functions in plants, including the ability to resist pest and disease, cold, drought, salinity, and other adversity stresses.
In the process of drought resistance, plants can regulate the content or increase the activity of various antioxidant enzymes in the body. Salicylic Acid has a potentiating effect on such responses. Dora’s team tried to soak corn seeds with a low concentration of salicylic acid under drought stress, and the germination rate, germination index, and vigor index were significantly increased.
Under the salt stress, Seed soaking with SA could increase the germination rate of mung bean seeds and the content of chlorophyll in seedlings, and reduce the content of MDA and proline in seedlings, thereby maintaining the integrity of the membrane. It can effectively alleviate the inhibitory effect of salt stress on the germination and growth of mung bean seeds, and induce the improvement of its salt tolerance. (Salicylic Acid Product)
S-ABA plays an important role in plant stress responses such as drought, high salinity, low temperature, and plant diseases and insect pests. Under adversity, plants start the abscisic acid synthesis system to synthesize a large amount of abscisic acid. It Inhibits stomata opening, promotes water absorption, and reduces pathways for water transport. Induce the synthesis of drought-resistant specific proteins and improve the stress resistance of crops.
Under drought stress, S-ABA can significantly reduce leaf water evaporation. Reduce leaf cell membrane permeability. Induces the formation of the biofilm system protective enzyme SOD. Leaf stomatal opening is inhibited or stomata are closed, thus reducing water transpiration and ultimately improving the water retention capacity and drought tolerance of plants. (S-ABA Product)
7. Silicon Fertilizer
After silicon enters the plant, it forms cutin (silicon double-layer structure) in the epidermal tissue below the cuticle of the leaf, which inhibits transpiration, reduces the evaporation of water from the plant, and improves the efficiency of photosynthesis and water utilization.
At the same time, silicon is deposited between the cell wall and the cuticle, which can reduce water loss and reduce wilting caused by excessive water loss under strong light, thereby improving the utilization of water by plants, thereby increasing the drought resistance of crops.
Many parasitic fungi infiltrate their hosts through the epidermal cell wall. Solid silicon combined with plant cell walls can create a physical barrier to prevent the infiltration of fungal hyphae and insect mandibles or larvae. At the same time, the cells are not easily decomposed by enzymes, thereby preventing the invasion of fungal hyphae along with the enzymatic hydrolysis.
Our experiments show that silicon can improve the resistance of rice to rice blast, brown spot and borer. Silicon deposits on the outer epidermis of plant cell walls, forming a physical barrier. This layer of barrier plays a major role in plant disease resistance and insect resistance.
8. Jasmonic Acids
Jasmonic acids are similar to polypeptide signal molecules, which can effectively regulate the process of plant growth and development and the ability of plant dwarf to adapt to the environment. It can successfully participate in the stress response of plants when they face various adverse environments. When the plant is threatened, the substance contributes to the expression of stress resistance genes in the plant and transmits the relevant information to other parts of the plant to achieve the establishment of system stress resistance.
Under low temperature stress, jasmonic acid treatment can significantly increase the activities of antioxidant enzymes such as SOD, POD and CAT in wheat seedling cells, increase the content of soluble protein, reduce the relative conductivity and MDA content, thereby maintaining the integrity of the cytoplasmic membrane, enhancing the The ability of wheat plants to resist low temperature stress.
Plant cells accumulate a large amount of proline when they are under stress, which plays a role in protecting plants from osmotic stress. Proline plays 5 roles in plant stress resistance.
1. Cytoplasmic Osmotic Regulators: As an osmotic regulator, proline transports proline into the cytoplasm when cells are under osmotic stress, and reduces the osmotic potential by increasing the cytoplasmic concentration, thereby maintaining the osmotic balance between cells and the external environment.
2. Cell Structure Protector: Proline is the most water-soluble amino acid among all amino acids and has strong hydration ability. When plants are damaged, proline interacts with proteins to stabilize and protect biological macromolecules and cell membrane structures.
3. Free-radical Scavenger: Proline is also a scavenger of various free radicals.
4. Involved in Nitrogen Metabolism and Energy Metabolism: When plants are under drought stress, their proteins will be decomposed in large quantities to produce NH3. Excessive NH3 accumulation will cause plant poisoning. Plants can convert the excess accumulated NH3 into other forms and store them for re-use for plant recovery after the adversity is relieved.
5. Adversity Stress Signal Substances: As a signaling molecule, proline can activate various responses related to adversity adaptation, and its metabolic intermediates can induce the expression of resistance genes. (Proline Proudct)
More and more biostimulant formulations containing anti-stress materials are welcomed by the market. They can not only improve crop quality and yield but also help farmers resist unknown risks. If have any questions about plant stress resistance, please contact our team.