ACS OMEGA, cilt.8, sa.31, ss.28207-28232, 2023 (SCI-Expanded)
Dynamic shifts in climatic patterns increase soil salinityandboron levels, which are the major abiotic factors that affect plantgrowth and secondary metabolism. The present study assessed the roleof growth regulators, including biochar (5 g kg(-1)) and gallic acid (GA, 2 mM), in altering leaf morpho-anatomicaland physiological responses of Solanum melongena L. exposed to boron (25 mg kg(-1)) and salinitystresses (150 mM NaCl). These growth regulators enhanced leaf freshweight (LFW) (70%), leaf dry weight (LDW) (20%), leaf area (LA), leafarea index (LAI) (85%), leaf moisture content (LMC) (98%), and relativewater content (RWC) (115%) under salinity and boron stresses. Physiologicalattributes were analyzed to determine the stress levels and antioxidantprotection. Photosynthetic pigments were negatively affected by salinityand boron stresses along with a nonsignificant reduction in trehalose,GA, osmoprotectant, and catalase (CAT) and ascorbate peroxidase (APX)activity. These parameters were improved by biochar application tosoil and presoaking seeds in GA (p < 0.05) inboth varieties of S. melongena L. Scanningelectron microscopy (SEM) and light microscopy revealed that applicationof biochar and GA improved the stomatal regulation, trichome density,epidermal vigor, stomata size (SS) (13 381 & mu;m), stomata index(SI) (354 mm(2)), upper epidermis thickness (UET) (123 & mu;m),lower epidermis thickness (LET) (153 & mu;m), cuticle thickness(CT) (11.4 & mu;m), trichome density (TD) (23 per mm(2)), vein islet number (VIN) (14 per mm(2)), vein terminationnumber (VTN) (19 per mm(2)), midrib thickness (MT) (5546 & mu;m), and TD (27.4 mm(2)) under salinity and boron stresses.These results indicate that the use of inexpensive and easily availablebiochar and seed priming with GA can improve morpho-anatomical andphysiological responses of S. melongena L. under oxidative stress conditions.