Agar--Widely used in agriculture

Agar—Widely used in agriculture

Agar (also known as agar-agar) is a natural seaweed polysaccharide. In the agricultural field, it has been extended from basic research to production applications due to its gelling properties, sustained release, and biocompatibility, especially in plant tissue culture, seed treatment, bioremediation, and other aspects. It has shown unique value. The following are its specific application scenarios and technical principles:

________________________________________

A. Core support materials for plant tissue culture

1. Culture medium solidifier

o Mechanism of action: Agar is usually added to the culture medium at a concentration of 0.6%-1.0% and forms a stable solid matrix through the thermoreversible gel property (solidification at 40℃, melting at 85℃), providing physical support for plant in vitro tissues (such as stem tips, embryos, callus tissues)

o Application example: In blueberry anther culture, agar-based culture medium induces callus differentiation, and with the environmental regulation of pH 5.8-6.0, the success rate is more than 70%; in the reproduction of rare orchid plants (such as Dendrobium officinale), agar fixes the protocorm and promotes its development into a complete plant

2. Technical advantages

o Aseptic environment guarantee: The chemical inertness of agar avoids interfering with the activity of plant hormones (such as auxin and cytokinin), ensuring that the tissue differentiation process is controllable

o Convenience of operation: Compared with liquid culture, solid culture medium reduces the risk of contamination and facilitates observation of growth status and subculture transfer

________________________________________

B. Seed treatment and coating technology innovation

1. Seed coating carrier

o Formula design: Mix agar powder (concentration 1%-3%) with plant growth regulators (such as gibberellins), nutrients (such as potassium dihydrogen phosphate), and fungicides (such as clothianidin) to make a coating solution, which wraps the surface of the seeds to form a degradable film

o Functional realisation:

▪ Slow release effect: The coating film slowly releases nutrients and pesticides in the soil, extending the protection period (such as increasing the germination rate of corn seeds by 25%)

▪ Physical protection: Reduce mechanical damage during sowing and block soil-borne pathogens (such as Fusarium) infection

2. Economic benefits

o Reduce repeated application of pesticides by 30%-50%, reduce production costs, and are especially suitable for field crops such as corn and rice

________________________________________

C. Agricultural seedling cultivation: degradable nutrient pots

1. Structural design and function

o Mix agar (5%–10%) with humus, vermiculite, and slow-release fertilizer, and mold it into columnar or cup-shaped nutrient pots

o Core features:

▪ Water retention and fertilization: The gel network locks in moisture, reduces watering frequency by 50%, and slowly releases nutrients to the seedling roots

▪ Environmentally friendly and degradable: After transplanting, the nutrient pots naturally decompose into organic matter in the soil, without plastic pollution

2. Application cases

In tomato seedling cultivation, agar nutrient pots increase the survival rate of seedlings by 18% compared with traditional plastic pots and shorten the seedling recovery period by 3–5 days

________________________________________

D. Bioremediation and environmental governance

1. Pollutant degradation carrier

o Agar is mixed with specific microorganisms (such as petroleum-degrading bacteria Pseudomonas putida) and carbon sources to make bioremediation particles, which are then placed in contaminated soil or water

o Mechanism of action: The three-dimensional structure of the gel provides a habitat for microorganisms, promotes the expansion of the bacterial community, and accelerates the degradation of petroleum hydrocarbons (efficiency of 90%) or heavy metals (such as cadmium ion adsorption rate of 85%)

2. Ecological compatibility

o Compared with chemical remediation agents, agar-based preparations have no toxic residues and are suitable for in-situ remediation of farmland soil

________________________________________

E Pesticide slow release and green plant protection

1. Preparation of slow-release particles

o Agar (concentration 2%-5%) encapsulates the active ingredients of pesticides (such as imidacloprid) and controls the release rate through the gel network so that the drug effect lasts for 15-30 days and reduces the frequency of application

o Synergistic enhancement: Adding plant extracts (such as tea polyphenols) to enhance antibacterial properties, used for fruit and vegetable disease prevention (such as strawberry gray mold prevention and control)

________________________________________

F. Agricultural product preservation and post-harvest processing

1. Development of preservation pads

o Agar gel is compounded with natural antibacterial agents (such as rosmarinic acid) to make fresh-keeping pads that can be placed in fruit and vegetable packaging boxes, absorb ethylene and inhibit mold, and extend the shelf life of strawberries and blueberries by 7-10 days

Summary and Prospects

Agar has become a key material for upgrading modern agricultural technology due to its natural origin, biodegradability, and multifunctional properties:

• Current value: Extending from laboratory scenarios of tissue culture to field applications (such as seed coating and nutrient pots), significantly improving production efficiency and resource utilization

• Technical challenges: Gel strength needs to be optimized (such as nanocellulose enhancement) to cope with mechanical sowing pressure and reduce the cost of high-purity agar

• Future direction: Customized production of seedling pots combined with 3D printing technology, or development of biosensor-integrated coatings to monitor seed germination environment in real time

With the deepening of the concept of green agriculture, the innovative application of agar in sustainable agriculture will continue to expand, promoting the transformation of agricultural production towards high efficiency and environmental protection.