Effect of Temperature and Photoperiod on Triclopyr, Picloram, and 2,4,5-T Translocation

Abstract

The effects of photoperiod and temperature on the translocation of triclopyr {[1(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid}, picloram (4-amino-3,5,6-trichloropicolinic acid) and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] were studied on tanoak [ Lithocarpus densiflorus (Hook. & Arn.) Rehd.], snowbush ceanothus ( Ceanothus velutinus Dougl.), bigleaf maple ( Acer macrophyllum Pursh), bean ( Phaseolus vulgaris L. var. ‘Red Kidney’) and barley ( Hordeum vulgare L. var. CM-67). Isolation of 14 C and analysis for the radioactive herbicides revealed little metabolism of the herbicides. Regardless of herbicide or plant species herbicide movement was greatest under warm temperature and long day conditions. Among the herbicides tested, 14 C associated with triclopyr was the most mobile in each species. Each herbicide moved readily in the symplast but root applications of each herbicide revealed limited apoplastic mobility.