HPLC-analysis of the concentrations of free asparagine and glutamine in potato tubers grown with varying amounts of nitrogen

Summary The paper describes the rapid determination by HPLC of free asparagine and glutamine in potato tubers. The method has been applied to tubers from experiments in pots to which differing amounts of nitrogen had been added. Increasing levels of N-fertilizer, applied in inorganic or organic form, increased the concentrations of asparagine and glutamine in the tuber dry matter as well as their amounts per pot. amide concentrations are significantly correlated to those of crude protein (P<-0.001) and nitrate (P<-0.01).