The effects of different plant growth regulators and culture durations on vascular bundles and rooting of lentil (lens culinaris medik ssp. culinaris) under in vitro conditions

This experiment was conducted at Usak University, UBATAM central laboratory, between the years of 2018 and 2020. The effects of cytokinin and auxins on plant development and vascular bundles were investigated on the lentil in vitro conditions. Lentil cultivar of "Çiftçi" was used as plant material. 2 cm long shoots obtained from robust lentil seedlings were used as explants which germinated under in vitro conditions. The explants were treated with different concentrations of BAP (1 mg/L) and NAA (0,3, 0,6, 0,9, 1,2 mg/L) along with control and their development at 7, 14, 21, 28 and 35 days of culture was examined. The experiment was established in completely randomized factorial experiment design in 3 replications. Shoot length, number of shoots per explant, rooting, width of phloem and xylem regions and stem radius were measured. Using 7 and 14 day culture periods, plants showed healthy growth at all BAP and NAA concentrations. While the highest phloem region width (89.13 µm) was observed in the control group, the highest xylem region width (196.99 µm) was obtained from 1 mg / L BAP treatment. Prolonged day treatments and high doses of BAP and NAA treatments induced deformation and narrowing in phloem and xylem regions and stem radius. This narrowing in the vascular bundles effectively prevented rooting in the root zone. Rooting was observed only in the control groups at 21, 28 and 35 days of culture These results reveal negative effects of plant growth regulators treatments on prolonged days of culture and conclude that the time period of treatment must be optimized precisely to avoid damages to vascular and other tissues and promote desirable growth and development of tissues.