Impact of Resorcinol and Biochar Application on the Growth Attributes, Metabolite Contents, and Antioxidant Systems of Tomato ( Lycopersicon esculentum Mill.).

Climate variability has been a catalytic factor in inducing both biotic and abiotic stresses, exerting detrimental impacts on crop yields. This, in turn, leads to the manifestation of biochemical and physiological impairments within plant systems. This study aimed to evaluate the effects of different concentrations of resorcinol and biochar on tomato ( Lycopersicon esculentum Mill.) growth, primary and secondary metabolites, and antioxidant enzyme content levels. Biochar was synthesized from Cedrus deodara (Roxb. ex D. Don) G. Don, sawmill shavings using pyrolysis and subjected to comprehensive characterization employing contemporary techniques including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and UV-vis spectroscopy (UV). Both resorcinol at 0.1 μM/L and biochar at 30 mg/L significantly enhanced tomato seed germination and plant growth, promoting increased shoot/root length and fresh/dry weights in tomato plants compared to controls. This supplementation also amplifies tomato chlorophyll contents, growth metabolites, and antioxidant enzyme activities, contributing to robust plant development. Resorcinol at 0.1 μM/L concentration significantly enhanced total protein (79.9 μg/g), total phenol (58.8 μg/g), total proline (0.03 μg/g), total lipid (3.8 μg/g), total soluble sugar (42.5 μg/g), and flavonoid (0.09 μg/g) as compared to control. Biochar at 30 mg/L concentration showed maximum values of total protein (92.1 μg/g), total phenol (61.3 μg/g), total proline (0.03 μg/g), total lipid (5.5 μg/g), total soluble sugar (48.9 μg/g), and flavonoid (0.08 μg/g). This research indicated that foliar application of these specific concentrations of resorcinol and biochar has the ability to improve tomato plant growth, osmolytes, and antioxidant activity.