Development of a novel protocol for enhanced tomato callus formation and growth through the use of medicinal Plant extracts

Abstract Medicinal plants and their derivatives have been used for centuries in various sectors beyond treatment and nutrition. However, the use of toxic chemicals such as pesticides, fungicides, and herbicides has led to environmental pollution, necessitating the search for eco-friendly alternatives. Medicinal plants and their compounds offer a promising solution due to their naturalness and biodegradability. An in-vitro experiment was conducted at Gorgan University in 2022 to test the impact of six medicinal plant extracts on tomato growth and callus induction. Two concentrations of 50 and 100 mg/L were added to the Murashige and Skoog (MS) medium culture. Results showed a 100% increase in germination speed and an increasing trend in stem length (SL), with the 50 mg/L Juniperus sabina treatment yielding the highest amount. The amount of callus growth (CG) and weight (CW) increased by 50% and over 200%, respectively, with the Taraxacum officinale 100 and Conocarpus erectus 50 mg/L treatments producing the best results. More than 90% callus formation was observed compared to the control. Biochemical analysis revealed that the extracts were rich in phenolic compounds (348 mg/g of total phenol), flavonoids (162 mg/g), antioxidants (61%), and auxin. Antioxidant and plant growth regulators (PGR) content and the stimulation of the plant's defense system likely contributed to the results. Plant extracts also affected the biochemical content of calluses, with the exception of total phenol. Using plant extracts to increase growth and reduce time for callus induction is recommended in tomato tissue culture. However, optimal concentration and combination of medicinal plant extracts for different plant species and growth conditions require further research.