Effects of Canavanine on Arginine Utilization in Plants with Special Reference to Mitotic Activity

Publisher Website
Google Scholar
Abstract
Excised primary roots ofPhaseolus vulgarisL. were treated with canavanine and the effect on arginine utilization was studied. Arginine utilization was observed to be depressed to a low level by canavanine (1.8 × 10−4M) in rapidly dividing and growing tissues. In addition, canavanine inhibited arginine utilization to a lesser degree in root sections composed of mature and non‐dividing tissues. This demonstrated that canavanine inhibition is not limited to those tissues where active DNA synthesis occurs.Canavanine was observed to inhibit the onset of mitosis in primary roots as evidenced by a significant reduction of the frequency of mitotic figures. In addition, this amino acid was found to affect the course of mitosis once it was initiated by altering the relative frequency of mitotic stages, decreasing the percentage of prophase figures and increasing the percentage observed in the telophase. An influence on the rate of spiralization and despiralization of the chromosomes is suggested. The effects on mitosis are probably related to growth‐inhibitory and toxic effects of canavanine. The possible function of canavine as an allelopathic substance is hypothesized.