Plant biostimulants: A Novel Strategy to Boost Crop Production

Saptaparna Dasgupta, Bennett University

Plant biostimulants are novel products used to boost cultivation and becoming widespread in sectors such as agriculture and the chemical industry. Contrary to typical crop inputs, such as fertilizers or pesticides, biostimulants are distinctive. In this, a single substance may have several routes that affect crop growth and development. The influence of the biostimulants of the crops depends on the timing and location of the application. This article is focused on the major row crops grown in the US, such as maize (Zea mays), soybean (Glycine max), wheat (Triticum aestivum), etc. 

What are Biostimulants? 

Plant Biostimulants are substances or microorganisms that when applied to the seeds, plants, or the rhizosphere it enhances nutrient uptake and efficiency, abiotic stress tolerance, crop quality, and production. To put it in simple words, bio stimulators work analogously to biofertilizers, plant probiotics, and plant metabolic enhancers. Biostimulants have been used for several years in commercial farming. However, the number of these compounds accessible to farmers and utilized by farmers has risen dramatically in recent years. Other items commonly included are seaweed extracts, organic acids, good microorganisms (like bacteria and fungus), protein hydrolysates or amino acids, and chitosan. Also, it comprises the categories which are less common but more frequent include microbe extracts, biochar, and concentrated enzymes. Apart from concentrated enzymes, plant biostimulants differ widely in their composition. This is due to the biological origin of the several constituents, which results from synergy between components rather than individual components. This further indicates that the action of the biostimulant should be based on applicational efficiency.  

Seaweed Extract is a Plant Biostimulant 

The category of seaweed extracts comprises a broad variety of plant biostimulants. It is produced from the processing of various algae species, most commonly from macroalgae (seaweeds). Microalgae stand to be a renewable source of biostimulants and are stringently monitored for continuous production and supply. Brown algae contain, in abundance, a specific group of carbohydrates, such as alginate, fucoidan, and laminin. Whereas, on the other hand, carrageen is vastly found in red algae and ulvan in green algae. Research shows that fucoidan, carrageen, and ulvan are highly sulfated compounds. Thus, the ease of its extraction stands to be the key to reducing the build-up of sulfhydryl compounds that hinder the growth of crops. Application of seaweed extract biostimulant provides antioxidant effects and is known for stress relief. Antioxidant effects have proven their potential in the reduction of cell damage from reactive oxygen species (ROS). ROS poses a threat to the crops when the plant is under abiotic or biotic stress. Along with carbohydrates, it also contains certain crucial plant hormones, such as brassinosteroids, polyamines, and betaines. These help in enhanced plant responses expressed as enhanced quality of crops and high yield. 

Humic and Fulvic Acid as Biostimulants 

Soil is a rich source of organic matter, which can produce a variety of stable chemical compounds, known as humic acid and fulvic acid. These acids are soluble in alkaline solvents but are insoluble in acidic solvents. On the other hand, fulvic acids are soluble in both acidic, as well as alkaline solvents. Ancient research proves that these acids are stable and undergo irreversible reactions. This makes these acids potent in the stimulation and induction of the soil microbiome. These acids have high carbon content, which serves as a direct source of energy for various microbes in the soil. The reaction thus serves as an inducing activity, which leads to improved quality of the soil. Humic acid also has auxin-like effects on plants, which helps in root elongation and initiation of root hairs, leading to enhanced nutrient uptake. 

Nitrogen-Fixing Bacteria as Biostimulants 

As crops cannot utilize the nitrogen directly from the atmosphere, they require nitrogen-fixing bacteria, which converts nitrogen to ammonia. The conversion takes place via the nitrogenase enzyme. The activity of nitrogenase could irreversibly be inhibited by the presence of oxygen. To overcome this issue, nitrogen-fixing bacteria have developed various mechanisms to protect the enzyme under aerobic conditions. Elevations in the supply of nitrogen, through a furrow in the soil, near to the roots have turned out to be a great fertilizer, and thus, act as a biostimulant. 

Significance of the study

Biostimulants, such as extracts of seaweed, can provide unlimited uses. All components in a product are typically unknown to their entire makeup. This is particularly the case with seaweed extract, humic acid, and fulvic acid. However, it is most commonly employed for supplying the nutrients needed to promote a culture at a specified yield level independent of its source and manner of administration. The versatility of particular items with relation to the desired response is where bio-stimulants initially diverge from other agricultural inputs. Though not strictly novel biostimulants, the number of products available has increased during the previous two decades. Biostimulants can thus influence the crop and soil system for improved productivity and yield. Present scenario highlights, the approach for the usage of biostimulants in a row crop system. Although numerous biostimulants are used to boost production, many products do this through influences on soils and root biology. A better assessment of soil quality impacts might uncover previously undiscovered benefits for use of biostimulants.

Also read:Approaching Migraine via arterial spin labelling technique

Source:

1. Sible, C. N., Seebauer, J. R., & Below, F. E. (2021). Plant biostimulants: A categorical review, their implications for row crop production, and relation to soil health indicators. Agronomy, 11(7), 1297. https://doi.org/10.3390/agronomy11071297
2. Quinn, L., & Urbana-Champaign, U. of I. at. (n.d.). Kelp for corn growth? Scientists demystify natural products for crops. Retrieved 16 July 2021, from https://phys.org/news/2021-07-kelp-corn-growth-scientists-demystify.html

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About the author: Saptaparna Dasgupta, currently a B. Tech 3^rd year student, pursuing Biotechnology, is a diligent student and determined in terms of her career goals. Being a budding biotechnologist, she is open to all research fields of her course and passionate about knowledge. She is focused and constantly tries to improve her writing skills, also a project enthusiast and is fond of gaining hands-on experience in laboratories. She believes that all hard works and effort pays off eventually and follows this as the motto of her life.