Comparative Volatility of Various Forms of 2,4-D

Publisher Website
Google Scholar
Abstract
Young, rapidly growing bean and tomato plants were enclosed in bell jars and cellophane cases together with 2,4-dichlorophenoxyacetic acid (2,4-D) and various salts and esters of this acid in a study of the relative volatility of these herbicides. Pure forms of the chemicals were used, and none of them was permitted to come in direct contact with the test plants. Any plant growth-regulating effects, such as epinasty, bud inhibition, or formative effects, that subsequently developed were accordingly the result of vaporization of the chemicals and movement of the vapors through rather static air onto the test plants. On the basis of this rather sensitive biological test the acid, Na salt, triethanolamine salt, and amide forms of 2,4-D were nonvolatile. All esters that were tested (the methyl, ethyl, butyl, isobutyl, amyl, isoamyl, isopropyl, allyl, phenyl, beta-chloroethyl, n-octyl, andoctadecyl) volatilized and produced growth effects on the test plants. Certain esters, namely, the methyl, ethyl, butyl, and isopropyl, appeared to be more volatile than the others tested; but, when present in high concns. and in close proximity to the plants, very little difference in relative volatility could be detected among the various esters. When dissolved in certain oils, such as diesel, corn, or cottonseed, the colatilization of the esters was greatly reduced. Other oils, such as Varsol, kerosene, motor oil (S.A.E. 20 or 50), and castor oil, had very little effect, if any, in reducing volatilization. Young test plants that were inclosed for a period of 1 week with the octa-decyl ester dissolved in diesel oil and then grown to flowering failed to show any growth effects, while comparable plants subjected to vapors of the ester alone developed severe formative effects on leaves and stems.

This publication has 0 references indexed in Scilit: