Effects of light, carbon dioxide, and hormone levels on transformation to photoautotrophy of sugarcane shoots in micropropagation

Sugarcane (Saccharum spp.) shoots were transferred from a heterotrophic mic ropropagation environment and cultured on sugar-free Murashige and Skoog (M S) salts medium in the controlled atmosphere of a growth chamber. The purpo se was to achieve photoautotrophic shoot culture to be used for micropropag ation. Effects on the shoots were tested for three factors: Carbon dioxide concentration, light level, and the hormone concentration of the growth med ium. Factorial design was applied for the experiment such that all combinat ions of high and low factor levels were utilized, and the medium level of e ach factor level constituted the middle point of the design. All shoots wer e observed to become yellowish in color and lose vigor in the sugarless env ironment, although the successful treatments regained their color and vigor . Average dry weights of shoots per vessel were recorded at the end of two weeks as a quantitative measure of transformation of shoots to photoautotro phy. Light and CO2 levels were found to have statistically significant and positive effects. The negative effect of hormone concentration was insignif icant.