Effect of humidity on somatic embryogenesis in cotyledon explant culture of carrot

Abstract

In order to clarify the influence of low humidity culture on the structure and function of somatic embryo the cotyledon expiants ofDaucus carrota L. cv. Hongshim were cultured in the petridish whose lids had holes sealed with millipore filters. In the low humidity culture, the production of somatic embryos was enhanced and their maturation promoted but the cotyledon structure of somatic embryos were nearly similar to control. In addition, the low humidity culture improved the germination of somatic embryos. Especially, the germination frequency of jar-shaped embryos was much improved (68%) in comparison with that of jarshaped embryos formed in constant humidity culture (23%). But low humidity culture at its extreme became an obstacle to normal plant regeneration in that precocious embryos were generated and the primary embryos turned into callus and formed secondary embryos. Therefore it is suggested that moderately low humidity culture (80–90% R.H.) is important to the higher production and better-quality of somatic embryos.