Effect of sugars and amino acids on androgenesis of Cucumis sativus

The effects of sugars (sucrose, maltose, glucose and fructose) and amino acids (glutamine, glycine, arginine, asparagine and cysteine) on embryogenesis and plantlet regeneration from cultured anthers of Cucumis sativus L. cv. Calypso and Green Long were studied. Type and concentration of sugar and amino acid influenced embryogenesis. Among the different sugars tested, sucrose was the best for embryo induction with an optimal concentration of 0.25 M. Maximum of 72 and 80 embryos per 60 anthers of Calypso and Green Long, respectively, were induced on embryo induction medium [B5 (Gamborg, Miller and Ojima (1968) Exp. Cell Res. 50: 151-158) supplemented with 2.0 muM 2,4-dichlorophenoxyacetic acid (2,4-D), 1.0 muM 6-benzyladenine (BA)] containing 0.25 M sucrose. The addition of amino acids to the embryo induction medium improved embryo yield with a combination of amino acids (glutamine, glycine, arginine, asparagine and cysteine of 1.0 mM each) giving the best response. Embryo differentiation was achieved on B5 medium supplemented with 0.25 muM of alpha-naphthaleneacetic acid (NAA), 0.25 muM kinetin (KN) and 0.09 M sucrose. Embryos were converted on B5 medium supplemented with abscisic acid (ABA) (10 muM) and 0.09 M sucrose. Embryos that developed on B5 medium supplemented with a combination of amino acids (glutamine, glycine, arginine, asparagine and cysteine of 1.0 mM each) exhibited the highest plantlet regeneration frequency.