Effect of AMA on Synthesis and Utilization of Food Reserves in Purple Nutsedge

Abstract

Chemical analyses for carbohydrates, fats, and protein and C14O2 tracer techniques were employed to study the influence of repeated applications of amine methylarsonate (hereinafter referred to as AMA) on food reserves in purple nutsedge (Cyperus rotundus L.). Purple nutsedge plants were grown under greenhouse conditions and treated at 3-week intervals with an aqueous solution of AMA. Chemical analyses suggested that repeated applications of AMA accelerated starch hydrolysis in tubers but had little effect on the fat and protein content. The disappearance of starch was correlated with an increase in the arsenic (hereinafter referred to as As) content of tubers following repeated applications. In leaf tissue, applications of AMA significantly reduced the sugar content and increased the protein content. Tracer studies on the rate of C14O2 fixation and evolution suggested that, in general, AMA-treated plants had a higher rate of utilization of the products of photosynthesis than untreated plants. Apparently, the carbohydrate fraction of food reserves was utilized in preference to fats and protein.