Effect of Bulb Size on Growth, Development and Starch and Sugar Contents of <I>Ornithogalum arabicum</I>

Abstract

Effect of bulb size on growth, development and contents of starch and sugar of   Ornithogalum arabicum were studied. In this study, there were 2 experiments. Experiments  I, effect of bulb size on growth and development of  Ornithogalum arabicum was conducted. There were 6 treatments, bulb diameter > 5 cm., 4 – 5 cm., 3 – 4 cm., 2 – 3 cm., 1 – 2 cm. and < 1 cm. The results showed that difference of bulb size had effects on growth and development of   O. arabicum. The plants grown from large bulb (more them 5 cm. in diameter) gave better growth and quality of flowers than smaller bulb (least 1 – 5 cm. in diameter) by mean of plant height, number of leaf per plant, inflorescence stalk and number of floret per plant. However, the number of day from planting to flowering of large bulb was longer than that of small bulb. Bulb size smaller than 1 – 3 cm. in diameter could develop in vegetative growth without flowering.
Experiment II, effects of bulb size on contents of starch and sugar were tested. Three bulb sizes were utilized, bulb diameter > 5 cm. (Grade J), 4 – 5 cm. (Grad A) and 3 – 4 cm. (Grade B). Plants were sampled at different stages of growth, planting stage, vegetative stage (4 weeks after planting), reproductive stage (17 weeks after planting) and dormancy stage. It was found that starch and sugar contents of  large bulb were greater than those of small bulb. The starch and sugar contents in leaf, root and inflorescence were less than those in bulb. At beginning of growth and development, sugar and starch content decreased. However, during flower development amount of sugar content increased. When plant went to dormant stage, amount of sugar content decreased whereas amount of starch content increased.