Phytotoxicity of Herbicides as Measured by Root Absorption*

Abstract

Summary. The phytotoxicity of numerous herbicides was measured on cucumber, sorghum, and wheat plants in terms of the minimum lethal concentration of herbicide in nutrient solution surrounding the roots of photosynthetizing plants. Wheat and cucumber were about equally sensitive as test plants, while, sorghum at a similar growth stage required ten to one hundred times the concentration (on a molar basis) of most chemicals for lethal effect. Only paraquat as a root‐absorbed herbicide appeared to be completely non‐selective to all three species. The triazines showed considerable selectivity to sorghum; of all the triazines tested only CP‐17029 was more toxic to wheat and sorghum than to cucumber. None of the compounds were ethal at a concentration of 10−7 molar (7.00, expressed as the negative logarithm); the triazine G‐34360 (desmetryne) showed the greatest toxicity (6.85) to the cucumber plant. Diuron on the same species had a toxicity rating of 6.69 and bromacil 6.72. Mesure de la phytotoxicité des herbicides au moyen de l'absorption radiculaire

Sensibilidade de plantas de arroz ao herbicida bispyribac-sodium em função de doses e locais de aplicação

“…A intoxi ca çã o do si st em a ra di ca l, me sm o se m reflexos visíveis na parte aérea, pode levar a perdas na produtividade de grãos (Hilton & Nomura, 1964;Blancaver et al, 2002).…”