The effect of boron on calcium uptake and growth in micropropagated potatoplantlets

Boron (B) requirements differ widely among plant species and the concentrat ion range between toxicity and deficiency is less for B than for any other nutrient. Excess B can adversely affect calcium (Ca) uptake and plant growt h. Potato cvs Bintje and Norland plantlets were micropropagated on Murashig e & Skoog (MS) nutrient medium, supplemented with 3 (MS control level) or 9 mM Ca, and a range of H3BO3 levels (0.025 to 0.300 mM B). Medium B levels of 0.100 and 0.300 mM decreased Ca content in leaves and shoots of cv. Norl and, but not Bintje. Medium B level of 0.025 mM, which is 25 % of the contr ol MS level, enhanced Ca uptake in cv. Norland and did not compromise norma l plantlet growth in either cultivar. This lower H3BO3 level (0.25 mM B), a nd a B-free gelling agent such as Gelrite, could be used for micropropagati on of potato and possibly other species susceptible to Ca deficiency disord ers.