Salt stress severely limits global crop productivity by disrupting ionic balance, physiological processes, and cellular ultrastructure, particularly in salt-sensitive forages like alfalfa (Medicago sativa L). Addressing this issue requires environmentally feasible and innovative strategies. This study investigated the comparative potential of Nano-FeO and FeSO4 (30 mg kg-1) soil supplements with rhizobium on alfalfa salt tolerance employing morphological, physicochemical, and cellular approaches. The results demonstrated that FITC-nFeO and rhizobium significantly reduced Na+ uptake, enhanced K+ accumulation, and improved the Na+/K+ ratio in alfalfa roots and shoots relative to FeSO4. Scanning electron microscopy illustrated that FITC-nFeO ameliorated root ultracellular structure and leaf stomatal functionality, facilitating improved gaseous exchange characteristics and photosynthetic performance. Confocal laser scanning microscopy confirmed FITC-tagged nFeO adhesion to roots, supported by transmission electron microscopy findings of preserved chloroplast ultrastructure under FITC-nFeO and rhizobium application. FITC-nFeO also mitigated oxidative damage of ROS, as evidenced by reduced hydrogen peroxide, electrolyte leakage, and thiobarbituric acid reactive substances (TBARS) content, through enhanced antioxidant enzyme activities. Overall, in comparison to FeSO4, FITC-nFeO with rhizobium retrieved the salt-induced damages in alfalfa by promoting morpho-physiological and ultracellular integrity. This study highlights the role of nanotechnology in enhancing the resilience of forages on salt-contaminated soils, paving the way for eco-friendly remediation strategies.

Sudden wilt syndrome of chilli, an emerging and destructive disorder, is characterized by an abrupt appearance that has increased in Indo-Gangetic alluvial plains over the past decade. The primary cause associated with the problem is water stagnation that creates hypoxic conditions in the root zone, and the plant mortality is further aggravated by soil-borne fungi Fusarium oxysporum. The effects of sudden wilt on chilli roots were studied morphologically and histologically, using root scanning, optical microscopy and electron microscopy. Significant changes with respect to root length, projected area, number of root tips and root segments, average root diameter as well as estimated volume of roots were observed via root scanning of healthy and diseased root samples. Through optical microscopy of sections of the microtome-cut root junctions displayed normal epidermis in healthy plants, while swollen cells indicated stress in the diseased plants. Cells of laterals and root tips in healthy plants were intact and stained strongly, but because of damaged tissues, cells in diseased plants were macerated and stained weakly. Root tips of healthy plants contained mitotic zones, whereas diseased root tips lacked mitotic zones. Electron microscopy studies revealed that sudden wilt had an adverse impact on xylem diameter, stele diameter, epidermal thickness and cortex thickness as evidenced by significantly lesser values of these parameters. The present study is the first systematic attempt to examine the morphological, histological and ultrastructural changes in chilli in response to sudden wilt syndrome.