Plant metabolic studies of the growth regulator maleic hydrazide

Abstract

The metabolism of maleic hydrazide has been studied in cell suspension cultures of soybean, wheat, and maize under standardized conditions (40 mL flasks, 1 ppm, 48 h). Maleic hydrazide was converted to its beta-D-glucoside as the predominant soluble metabolite in yields of between 2 and 15%. The latter was completely cleaved under simulated stomach conditions (pH 1, 37 degrees C, 24 h). In addition, up to 18% of the applied maleic hydrazide became associated with the nonextractable residue. The residue from soybean cells was solubilized only to a low degree (approximately 3%) under simulated stomach conditions. The lignin and hemicellulose components appeared to contain most of the radioactivity in the nonextractable residue from soybean cells. It is concluded that metabolism in cultured plant cells resembled that in whole plants and that the beta-D-glucoside of maleic hydrazide belongs to the small group of acid-labile pesticidal conjugates.