The potassium requirement for growth and embryogenesis in wild carrot suspension cultures

Artículo

A requirement for potassium for growth and forembryogenesis in suspension cultures of wild carrot (Daucus carota L.) was demonstrated. The concentration of K+ required for maximal growth (1 mM) was less than that required for maximal embryogenesis (20 mM). Neither Na+ nor NH4+ could replace K+. Ammonium ion enhanced embryogenesis when K+ was present at suboptimal levels greater than 1 mM. Nitrogen sources strongly influenced growth and embryogenesis, but the effects of nitrogen were separable from those of K+. Subline differences were noted. Subline CSC-29 produced nearly half the maximum embryo number in 1 mM K+ while CSC-31 produced no embryos at that K+ concentration. Growth of CSC-29 was slightly repressed by Na+, but no more than by similarconcentrations of K+. Growth of CSC-31 in 1 mM K+ was strongly repressed by Na+. Embryogenesis in CSC-29 was unaffected by Na+. In CSC-31, Na+ repressed embryogenesis at lower concentrations of K+.