optimizing callus induction and analyzing in vitro phytochemicals in san pedro cactus (echinopsis pachanoi)

Purpose: the objective of the present study was to examine the impact of explant type and varying concentrations of 2,4-dichlorophenoxyacetic acid and 6-benzyladenine growth regulators on the san pedro cactus callus morphological and biochemical characteristics. research method: four types of explants were used i.e. explants with areola, without areola, with truncated areola, and with central tissue. additionally, five combinations of ba and 2,4-d, were tested (0 mg/l ba + 2 mg/l 2,4-d, 2 mg/l ba + 2 mg/l 2,4-d, 3 mg/l ba + 3 mg/l 2,4-d, 4 mg/l ba + 4 mg/l 2,4-d, 0 mg/l ba + 0 mg/l 2,4-d). findings: the results indicated that callus formation induced in all treatments 6 days after inoculation. there were significant differences in growth parameters, including fresh weight, volume, moisture, tissue firmness, total phenols, total flavonoids and antioxidant activity of the callus (p < 0.01) and dry weight of callus (p < 0.05). explants holding a segment of central tissue, yielded the least favorable results in most of experimental treatments, and the application of 2,4-d in the absence of ba had an inhibitory and toxic effect on the san pedro cactus explants. research limitations: no limitations were found. originality/value: specifically, use of 2 mg/l ba + 2 mg/l 2,4-d and explants with areola resulted in callus with higher fresh weight, volume and total flavonoids, as well as good tissue integrity and firmness. the reported results are a valuable resource for future research related to cell tissue culture and the elicitation of secondary metabolites in echinopsis spp.