Proteolytic response of Zea mays L. hybrids to citric acid treatment

Hybrids of Zea mays L. (Buffalo, Falcon, H360 y HV313) were treated with citric acid (2000 ppm). The grain yield, the soluble protein and the proteolytic activity were monitored in the physiological maturity stage of the crop. The citric acid was applied before the appearance of the flag leaf, induced an increase in the production of the grain from 540 to 945 kg.ha^-1, in the soluble protein from 1.39 to 4.2 mg.mg d.w^-1 and into the proteolytic activity from 2 to 12 times in the Falcon, H360 and HV313 hybrids, while the Buffalo hybrid responded with less intensity to the treatment with citric acid. In the H360 hybrid treated with citric acid, an increase in the proteolytic activity of aspartyl serine proteases was observed. The results indicate that citric acid induces differentially, the proteolytic activity and the vigor of the corn hybrids analyzed.