The present research was aimed at evaluating the growth of brazilian ginseng (Pfaffia glomerata (Spreng.) Pedersen) in vitro cultured plantlets under two levels of nitrogen and sucrose, during six successive subcultures and acclimatization. Two nutritional treatments were tested: nitrogen at 100% strength of the MS medium + 30g L-1 sucrose; and nitrogen at 50% strength + 45g L-1 sucrose. During six successive subcultures, the explants of 30-day-old plantlets grown under both treatments were transferred, respectively to the next subculture on the same treatment conditions. At 6th subculture, plantlets were transferred to substrate Plantmax® Hortaliças and submitted to acclimatization in a growth chamber. Throughout the subcultures, fluctuations in growth response due to nutritional conditions tested were observed. The height of the higher sprout, the average height of sprouts, and the total number of nodal segments per plantlet, respectively for four, four and three subcultures were greater in 100% strength of the MS medium + 30g L-1 sucrose than in 50% strength + 45g L-1 sucrose. On the other hand, dry matter of roots, of shoots and of the whole plant, respectively for two, two and three subcultures, were greater in 50% strength + 45g L-1 sucrose. In conclusion, the increase of sucrose associated with reduction of N level in the culture medium enhanced the biomass production, while the MS at full strength enhanced the growth based in sprout length and number of nodal segments. These differences concerning the biomass production observed during in vitro culture did not persisted in the acclimatization process ex vitro, where MS at full strength give rise greater growth in sprout length and number of leaves per plant.
Brazilian ginseng; micropropagation; seedling production; organogenic potential
