Toxicity and Translocation of Herbicides Supplied to Grape Rootings Through Solution Culture

Abstract

Grape rootings were allowed to absorb solutions of monuron, diuron, simazine, atrazine, amitrole, and 2,4-D for 3 days and then planted in pots to observe the development of injury. Other rootings were similarly exposed to solutions of carbon-14-labeled monuron, simazine, amitrole, and 2,4-D. Zinfandel grapes growing in barrels received soil applications of simazine, amitrole, and 2,4-D.

Monuron and diuron were more injurious to grape rootings than were simazine and atrazine. Amitrole was non-injurious. 2,4-D killed the roots when sufficiently concentrated, and the rootings died if new roots were not formed.

Monuron, simazine, and amitrole were readily absorbed by the roots and translocated to the leaves. The concentration of these compounds either did not change or increased in the culture solutions. These results suggest that there was no selective absorption of these compounds. 2,4-D was absorbed by the roots, but there was no movement to the shoots.

There was no evidence of appreciable retranslocation of monuron, simazine, or amitrole from the leaves of treated grape rootings. Little if any retranslocation of monuron occurred. Limited retranslocation occurred from the leaves of the simazine-treated rootings. It is suggested that the retranslocated materials were not simazine, but were breakdown products of simazine. The retranslocation of amitrole appeared to be limited in the grape; the carbon-14 becoming incorporated in the xylem.

The fruit from 3-year-old Zinfandel vines grown in treated soil in greenhouse containers showed no positive evidence for 2,4-D, amitrole, or simazine. There was a small amount of carbon-14-labeled material in the fruit of the simazine-treated vine. This was evidently decomposition products of simazine.