Biostimulants are natural substances proven to have a positive impact on plant growth
Biostimulants are natural and eco-friendly substances known for their positive impact on plant growth by enhancing plant metabolism and physiology when applied in minimal quantities. In this article, we delve into the detailed categories of the most common biostimulants, shedding light on their mechanisms and applications.
Seaweeds, constituting a vital component of marine coastal ecosystems with approximately 9000 species, play a key role in agriculture. Notable seaweed species such as ascophylum nodosum, Fucus spp, Laminaria spp, Sargassum spp, and Turbinaria spp are commonly employed. The biostimulant properties of seaweed extracts stem from the presence of plant hormones, including auxins, cytokinins, gibberellins, abscisic acid, and ethylene. The market offers a variety of seaweed extract products, ranging from simply crushed seaweed to extractions of active molecules, available in solid or liquid forms tailored for specific applications.
Peptides and Amino Acids
Peptides and amino acids, fundamental molecules in plant mechanisms as the building blocks of proteins, exert influence on crucial physiological functions. Bioactive peptides can modulate plant processes by binding to cell receptors regulating specific metabolic functions. Obtained from animal sources through collagen hydrolysis at high temperatures or from vegetal hydrolysates through enzymatic hydrolysis at low temperatures, these substances play a pivotal role in plant health. Organic regulations may limit the use of animal-derived peptides to the non-edible parts of crops.
Derived from the decomposition of plant, animal, and microbial residues, humic substances are integral constituents of soil organic matter. Categorized into humins, humic acids, and fulvic acids based on molecular weights and solubility, these substances significantly contribute to soil fertility. Their biostimulant effects primarily enhance root nutrition through diverse mechanisms, impacting physical, physico-chemical, chemical, and biological soil properties.
Plants themselves harbor numerous beneficial substances that can act as biostimulants. The uniqueness of each plant extract, determined by the plant's origin and extraction process, makes it challenging to pinpoint specifics. Nevertheless, plant extracts have a direct impact on crops without demanding excessive energy inputs.
Two major categories of beneficial microorganisms, namely beneficial fungi and beneficial bacteria, play crucial roles in plant health. Mycorrhizal fungi, representing the fungal category, form mutualistic symbiotic relationships with plant roots, enhancing nutrient and water absorption by increasing root surface area dramatically. Techniques for mycorrhizae production, whether in vivo or in vitro, impact their resilience to soil conditions. Additionally, certain fungi strains like Trichoderma stimulate plant development and productivity while promoting the colonization of the rhizosphere by other beneficial microorganisms.
Beneficial bacteria, on the other hand, settle within the rhizosphere, primarily influencing plant nutrition functions. Products available in the market, such as rhizobium and plant growth-promoting rhizobacteria, contribute to increased mineral absorption and enhanced resistance to abiotic stress.
In summary, a comprehensive understanding of these biostimulant categories provides valuable insights into the diverse and intricate ways in which natural substances can positively impact plant growth and overall crop health.