Impact of Chlorella vulgaris, Nannochloropsis salina, and Arthrospira platensis as bio-stimulants on common bean plant growth, yield and antioxidant capacity

Abstract

The use of bio-stimulants in agriculture has emerged as a promising strategy to improve crop growth and yield. One type of bio-stimulant that has gained attention is microalgae extracts, which are known for their high metabolic activity, bioactive compounds, and ability to enhance plant growth and development. To investigate their effectiveness, a pot experiment was conducted at the Experimental Farm of Helwan University in Egypt during the 2022 season. The experiment aimed to evaluate the efficacy of Chlorella vulgaris, Nannochloropsis salina, and Arthrospira platensis (Spirulina platensis) extracts as bio-stimulants, applied through foliar spray at concentrations ranging from 0.25 to 2.0%, on common bean plants. Analysis of algal extract showed that . N. salina had the highest content of promotive growth hormones gibberellins (GA3) (74.85 ± 2.7mg100 g−1 d.wt). and auxins (IAA) (34.57 ± 2.7µg 100 g−1 d.wt.) compared to Chlorella and Arthrospira..The results revealed that the application of C. vulgaris, N. salina, and A. platensis extracts at concentrations up to 1.0% significantly improved various growth parameters, such as root, and shoot length, number of leaves and flowers per plant, leaf area, and total fresh and dry weight per plant. These extracts also positively affected yield attributes, including the number and fresh weight of pods per plant, seed index, seed yield per plant, and per feddan [a unit of land area]. Furthermore, the application of these extracts increased the chlorophyll content index with the maximum values of CCI (17.95. and 17.81%) was obtained at 0.50% N. salina, followed by 0.50% C.vulgaris. In addition to increase in the capacity of both non-enzymatic antioxidants [such as total antioxidant capacity, phenolics, and flavonoids] and enzymatic antioxidants [including catalase and ascorbic oxidase]. The most promising results were observed with the application of N. salina, and C. vulgaris extracts at a concentration of 0.5%. Additionally, the extracts significantly reduced the content of oxidative stress markers, such as malondialdehyde, percentage of electrolyte leakage, and hydrogen peroxide, in common bean plants compared to the control group. Contrarily, the measured parameters were reduced, while the levels of oxidative stress markers and some antioxidants including peroxidase, ascorbic peroxidase, superoxide dismutase, glutathione peroxidase, and glutathione transferase were increased by three algal extracts at a concentration of 2.0%, compared to control plants. Additionally, the application of these microalgae extracts improved the quality parameters, proximate composition, seed energy, and mineral contents of the harvested seeds, with the most significant positive impact was observed at 0.5% concentration of algal extract. These findings demonstrate the successful and safe utilization of extracts from C. vulgaris, N. salina, and A. platensis at concentrations up to 1.0% as bio-stimulants to enhance common bean yields and improve the nutritional quality of dried beans for consumers.

Mitigating drought stress in wheat plants (Triticum Aestivum L.) through grain priming in aqueous extract of spirulina platensis

“…A significant enhancement in flag leaf agronomic features upon the administration of S. platensis aqueous extract (SPAE) for both unstressed (SPAE-Cont treatment) and stressed (SPAE + DS) plants was noted in both cultivars. This enhancement is consistent with previous studies showing that S. platensis can act as a biostimulant to enhance plant growth [ 68 ] and ameliorate stress [ 69 ]. The multifaceted benefits of the SPAE, even amidst water stress scenarios, can be ascribed to many intrinsic properties and external interactions.…”

The Roles of Plant-Growth-Promoting Rhizobacteria (PGPR)-Based Biostimulants for Agricultural Production Systems

“…Also, microalgae contain a large group of photosynthetic microorganisms that can produce diverse antioxidant components and colonize harsh environments, and several species of microalgae are known as important biostimulants due to their rich composition in phenolics, polysaccharides, phytohormones, fatty acids, chlorophyll, vitamins, and carotenoids [ 371 ]. Microalgal metabolites have been found to impact resistance to plants against abiotic stress, improve soil fertility, improve nutrient uptake from soil, and increase defense response against infection and pathogens [ 372 ]. It is also important to consider the important of Azotobacter due to its high plant growth promotion activities, nitrogen fixation, heavy metal tolerance, growth hormone production, and pesticide degradation [ 373 , 374 ].…”

An Evaluation of the Effectivity of the Green Leaves Biostimulant on Lettuce Growth, Nutritional Quality, and Mineral Element Efficiencies under Optimal Growth Conditions

“…Numerous compounds, such as phenolics and ascorbate, have antioxidant activity that, in addition to increasing tolerance to stress, enhance the nutritional quality of crops [44]. Various studies have found that the application of biostimulants derived from algae can increase the accumulation of these types of compounds and the global antioxidant capacity [45][46][47]. The results of the present experiment suggest that it was mainly the application of the 3 mL L −1 dose of the Green Leaves product that produced a higher foliar concentration of total phenols and anthocyanins, followed by the application of Green Leaves at the 5 mL L −1 dose, with an increase in their levels when both doses were applied compared with the control plants.…”