Abstract
In order to promote the growth of redifferentiated carrot (Daucus carota L.) plantlets in vitro in MS medium, changes in the concentration of the medium components and in the quantity of nutrient uptake were investigated. Eight somatic embryos of carrot were placed on medium-supports (made of formed polyester wool) containing 60 ml of MS medium with 1.5% sucrose in a culture vessel (60×60×100 mm) and cultured. From 1 week after placing, growth of the plantlets and concentrations of inorganic and sugar components were measured every week. Phosphate concentration of MS medium and growth rate of the plantlets decreased in the late stage of carrot tissue culture and phosphate uptake by the plantlets also decreased with increase of the dry weight. Phosphate added into the MS medium in the late stage of cultivation increased height and dry weight of the plantlets. It was found that the standard phosphate concentration in MS medium became insufficient in the late stage of cultivation of carrot plantlets, and adding supplement of phosphate into the medium promoted growth.
