Chitosan nanomaterials: A prelim of next-generation fertilizers; existing and future prospects.

Global agriculture is urgently seeking ways to mitigate the detrimental effects of conventional chemical fertilizers on the environment. Biodegradable, eco-friendly, renewable energy-sourced next-generation fertilizers could be an answer, allowing for improved nutrient use efficiency and a lower environmental footprint. During the last decade, agricultural research on chitosan nanomaterials (NMs) has expanded, demonstrating their usefulness in enhancing agricultural output not only as plant immune boosters but also via slow, controlled and target delivery of nutrients to plants. Chitosan NMs natively act as an abundant nutrient source of C (54.4-47.9 wt%), O (42.3-30.19 wt%), N (7.6-5.8 wt%), and P (6.1-3.4 wt%) to plants. Moreover, chitosan NMs can further functionalized by more nutrients payloads through its functional groups. The current review investigates the technical features of chitosan NMs as prospective next-generation fertilizers based on rationales. The review offers crucial insights into future directions, sources, production capacity of chitosan-based next-generation nanofertilizers for industrial-scale manufacturing.

Slow-release Zn application through Zn-chitosan nanoparticles in wheat to intensify source activity and sink strength.

Source activity and sink strength are important aspects to measure growth and yield in wheat. Despite zinc's extended functions in the amendment of plant metabolic activities, critical research findings are missing on mapping the elusive interplays of slow-release zinc (Zn) application from nanoparticles (NPs) in crop plants. The present study reports that slow-releasing Zn application through Zn-chitosan NPs bestows myriad effects on source activity and sink strength in wheat plants. Herein, effects of foliar application of Zn-chitosan NPs (0.04-0.16%; w/v) at booting stage of wheat crop were evaluated to quantify the source sink potential compared to ZnSO4. Zn-chitosan NPs endowed elevated source activity by up-regulating cellular redox homeostasis by improving the antioxidant status, cellular stability and higher photosynthesis. Cognately, in the field experiment, NPs (0.08-0.16%, w/v) significantly spurred sink strength by up-regulating starch biosynthesis enzymes viz. sucrose synthase (SUS), invertase (INV), ADP-glucose pyrophosphorylase (AGPase), soluble starch synthase (SSS) and accumulated more starch in developing wheat grains. Concomitantly, higher spike lengths without awns, significantly higher number of grains/spike, test weight (24% more than ZnSO4 treatment), yield (21% more than ZnSO4 treatment), biological yield and harvest index quantified the higher sink size to further validate the better sink strength in slow-release Zn application via chitosan NPs.