MXene-nanoparticles foliar application improves wheat morpho-physiological and biochemical traits under cadmium (Cd2+) stress: A novel sustainable approach

Cadmium (Cd²⁺) pollution is a persistent problem in the agricultural sector. Plants can be treated with nanoparticles (NP) to reduce heavy metal stress. MXene nanoparticles (MX-NPs) were tested for wheat Cd stress relief. Comparative confocal microscopy was used to examine the morphology, physiology, yield, biochemistry, antioxidant enzyme activity, and cell viability of the wheat plants. Cd-stressed plants exhibited a decline in morphological parameters and yield attributes, including leaf area (-49 %), root length (-35 %), shoot length (-18 %), seed weight (-37 %), seeds per plant (-69 %), root and shoot fresh weight (-55 % and -64 %), carotenoid levels (-40 %), total chlorophyll (-13 %), total soluble sugar (-29 %), total soluble protein (-39 %), antioxidant enzymatic activities (APX, CAT, and SOD by -16 %, -5 %, and -14 %, respectively), and nitrate reductase activity (-65 %) compared to the control group. Stress markers, including MDA (+270 %) and proline (+201 %), increased in plants exposed to Cd. Levels of total flavonoids (+481 %) and phenols (+92 %) were greater in the Cd-treated groups. Foliar application of MX-NPs (1000 ppm) significantly alleviated Cd-induced stress, as demonstrated by increases in shoot length and root length (+41 % and +39 %, respectively), seed weight (+69 %), seeds per plant (+99 %), carotenoid concentration (+30 %), chlorophyll content (+39 %), nitrate reductase activity (+60 %), and total soluble protein (+19 %) compared with the control group. The supplementation of 1000 ppm-MX-NPs with Cd (250 μM) in exposed plants led to an enhancement in antioxidant enzymes, with APX, CAT, and SOD increasing by 76 %, 81 %, and 84 %, respectively. Confocal microscopy revealed that MX-NPs increased cell viability following Cd exposure. In conclusion, MX-NPs foliar spray effectively reduced Cd-induced stress in wheat, promoting sustainable agriculture under 500 μM Cd stress.