Arsenic Toxicity Induced Changes in Growth, Photosynthetic Pigments, Antioxidant Machinery, Essential Oil, Menthol and Other Active Constituents of Menthol Mint (Mentha arvensis L.)

Oligochitosan fortifies antioxidative and photosynthetic metabolism and enhances secondary metabolite accumulation in arsenic-stressed peppermint

“…The deleterious effects of differential As concentrations were considerably mitigated by the application of ICn ( Table 1 ). Application of oligosaccharides manipulates vital plant metabolic events, improving their performance under normal and perturbed environmental circumstances (Ahmad et al, 2017 ; Sadiq et al, 2017 ; Singh et al, 2017 ; Nabi et al, 2019 ; Naeem et al, 2020 ). ICn enhances the growth in peppermint by recuperating plant metabolism through improved nutrient assimilation, photosynthesis, and enzyme activities (Ahmad et al, 2017 ; Jaleel et al, 2017 ; Ahmed et al, 2020 ).…”

“…Diminution in the total leaf chlorophyll content due to As toxicity can be accredited to the impaired chlorophyll biosynthesis due to As-mediated impairment of a vital chlorophyll biosynthesis enzyme (α-aminolevulinic acid dehydratase) and/or due to ROS-induced breakdown of chlorophyll pigments and chloroplast membrane lipids (Kumar et al, 2014 ; Pandey and Gupta, 2015 ; Asgher et al, 2021 ; Zhang et al, 2021 ). As toxicity reportedly hinders the light harvesting apparatus, impairing the photosystem II activity, and in turn impedes the photosynthetic electron flow across the chloroplast thylakoids, thereby diminishing the assimilatory power (ATP and NADPH) producing potential which is fundamentally indispensable to fuel up the carbon fixation reactions (Duman et al, 2010 ; Nabi et al, 2019 ; Asgher et al, 2021 ; Lukacova et al, 2021 ). The potential energy deficit uncouples electron transport in the thylakoids, discontinuing the ATP synthesis possibly due to the exchange of inorganic phosphate by As in photophosphorylation (Singh et al, 2006 ; Duman et al, 2010 ; Nabi et al, 2021 ).…”

“…Improved NR activity in the existing study finds correlation with the ICn-mediated enhancement in the photosynthetic activity. Carbon input into metabolism is essentially significant for the plant, and As toxicity is known to impair the same, inhibiting the net photosynthesis (Nabi et al, 2019 ). Thus, improved values of photosynthetic parameters in As-treated plants are undoubtedly indicative of the role of ICn in improved fixation and assimilation of CO 2 , which increases the carbohydrate content in the plant and in turn alleviates the deleterious effects of As ( Figure 3F ).…”

“…ICn increases the content of menthol probably by upregulating the reductase enzyme involved in its biosynthesis (Ahmad et al, 2017(Ahmad et al, , 2019b. As-induced reduction in the menthol content is endorsed to decreased photosynthesis and downregulation of imperative reductase enzyme involved in menthol biosynthesis (Nabi et al, 2019). As revealed from the biosynthetic pathway of terpenes in peppermint, the content of menthol increases at the cost of menthyl acetate, and vice versa (Ahmad et al, 2017).…”

Alterations in photosynthetic pigments, antioxidant machinery, essential oil constituents and growth of menthol mint (Mentha arvensis L.) upon nickel exposure

“…Exposure of HMs to aromatic plants causes a greater reduction in their physiology, metabolic and developmental processes, ultimately affecting the production of essential oil (EO) (Chand et al 2015;Nabi et al 2019;Choudhary et al 2020). Nickel affects the content and yield of EO in the case of various aromatic plants by causing an imbalance between the ROS scavenging and generation (da Silva et al 2012).…”