Bulb growth and carbohydrate metabolism in nerine sarniensis cultured in vitro

The effects of temperature, different levels of sucrose, sorbitol and phosphate in the medium on the development and carbohydrate composition of bulbs were studied. Bulbs grew faster under 25/22°C day/night temperature and 16/8 hours light/dark period in liquid medium as compared to 17/14°C day/night temperature under the same photoperiod in semi-solid medium. The carbohydrate content was higher in bulbs grown in semi-solid medium. In medium that contained 9 % sucrose bulb growth and leaf elongation were inhibited, and 6% sucrose in the medium gave the best effect on the bulb growth. Since the utilization of sucrose from the medium, even after 6 weeks was incomplete, P was elevated to allow optimal conversion of sugars to storage carbohydrates. Increasing the level of phosphates in the medium up to twice the MS concentration of P, intensified the utilization of carbohydrates by the bulbs.