Algal-Mediated Nanoparticles, Phycochar, and Biofertilizers for Mitigating Abiotic Stresses in Plants: A Review

Abstract

The excessive use of agrochemicals to ensure food security under the conditions of a growing population, global climate change, weather extremes, droughts, wasteful use of freshwater resources, and land degradation has created severe challenges for sustainable crop production. Since the frequent and abrupt environmental changes are outcompeting the existing agricultural technologies of crop production systems to meet food security, the development and use of modern technologies and nature-based solutions are urgently needed. Nanotechnology has shown potential for revolutionizing agri-production and agri-business in terms of nanofertilizers and nanoparticles for crop protection. Furthermore, in the recent past, biochar has been identified as a negative emission technology for carbon sequestration and soil fertility improvement. However, supply chain issues for biochar, due to feedstock availability, challenges its worldwide use and acceptability. Meanwhile progress in algae research has indicated that, algae can be utilized for various agro-ecosystem services. Algae are considered an efficient biological species for producing biomass and phytochemicals because of their high photosynthetic efficiency and growth rate compared to terrestrial plants. In this context, various options for using algae as a nature-based solution have been investigated in this review; for instance, the possibilities of producing bulk algal biomass and algal-based biofertilizers and their role in nutrient availability and abiotic stress resistance in plants. The potential of algae for biochar production (hereafter “phycochar” because of algal feedstock), its elemental composition, and role in bioremediation is discussed. The potential role of agal nanoparticles’ in mitigating abiotic stress in crop plants was thoroughly investigated. This review has effectively investigated the existing literature and improved our understanding that, algae-based agro-solutions have huge potential for mitigating abiotic stresses and improving overall agricultural sustainability. However, a few challenges, such as microalgae production on a large scale and the green synthesis of nanoparticle methodologies, still need further mechanistic investigation.

Biochar-Mediated Control of Metabolites and Other Physiological Responses in Water-Stressed Leptocohloa fusca

“…A plethora of studies have confirmed our current findings where MDA, H 2 O 2 , O 2 − , and OH − increased with an increase in drought severity [7][8][9]17,19,28,70]. In contrast, BC application substantially reduced ROS-mediated stress in L. fusca, which was also confirmed by the earlier studies [15,32,35,68,[81][82][83]. As well as ROS, recent studies revealed that, as a result of excessive lipid peroxidation, some reactive carbonyl species (RCS) are also produced, which cause oxidative injury to plant cells [11,84].…”

“…BC-2 also exhibited similar stimulation in the activities of antioxidants for both drought levels. Additionally in shoots, the amino acid content including Ala, Gly, Leu, Pro, Val, Trp, Tyr, Lys, Ser, Thr, Cys, Met, Asn, Gln, His, Arg, Glu, and Asp declined by 37,42,31,17,31,43,41,40,18,30,24,27,27,35,28,53,39, and 43% by 70% FC, and this reduction was 64,77,71,76,81,84,72,73,79,62,53,78,76,86,53,77,82, and 70% after the employment of 30% FC, respectively (Figure 6). Similar to the up-regulation of amino acids in roots, The shoots of L. fusca plants experienced 17, 25, 17, 39, 29, 26, 32, 55, 32, and 19% inhibition in organic acid content after 70% FC, and a 58, 75, 65, 68, 58, 71, 63, 85, 67, and 67% decline in CA, FA, LA, SA, BA, MA, PA, OA, GA I, and GA II following 30% FC, respectively.…”

Recent progress in bio-mediated synthesis and applications of engineered nanomaterials for sustainable agriculture

“…Algae are readily available and eco-friendly, with rich source of metabolites and optimum metal uptake capacity for use as reducing agents for nanoparticle synthesis ( Abideen et al., 2022 ; Hasnain et al., 2022 ). In addition, algae accumulate higher lipids and potential source of biodiesel using saline lands and brackish water.…”

Preparation of Seaweed Nanopowder Particles Using Planetary Ball Milling and Their Effects on Some Secondary Metabolites in Date Palm (Phoenix dactylifera L.) Seedlings

“…One of the most recent technologies that has attracted interest across several fields is nanoparticles (NPs). It is thought that the biological synthesis of NPs (using, for example, microorganisms such as bacteria, fungi and yeast, microalgae or plant extracts including macroalgae) is a secure, easy and environmentally friendly method that uses straightforward reducing agents rather than dangerous chemicals [ 14 ]. Numerous uses for nanoparticles (NPs) exist for preserving sustainable agriculture and healthy ecosystems as well as for resolving environmental and agricultural issues.…”