Growth regulators for chloroplast development in Jucarito-104 rice callus under light and dark culture

Abstract

In this study we identify appropriate conditions for early induction of chloroplast in rice callus. It were analyzed different combinations of 2,4-D and kinetin, and effect of light and dark on the quality of callus formation and plant regeneration. We found that1.0mg.l-1 of 2,4-D and 2.5mg.l-1 of kinetin were the best combination for the major average and quality of embryogenic callus obtained 21 day after culture, without significant effects respect to control without kinetin. Kinetin is a cytokinin that induces the development of plastids during callus formation. Callus formation under light was low efficient than at the dark one. In order to detect chlorophyll we used fluorescent microscopy for analysis of calli samples immediately before transferred them to regeneration media, and 12, 24, 48 and 72 hours after. Only 24 hours of incubation on regeneration media were sufficient to detect chlorophyll by fluorescent microscopy. Uncountable fluorescent clusters were observed at 72 hours. In callus formed without kinetin chlorophyll were detected four days after culture as small fluorescent spots. Key words: chlorophyll, cytokinin, regeneration