The uptake and translocation of 2,4,5-T in gorse (Ulex emopaeus L.)

The uptake of 2,4,5-T by spines of gorse (Ulex europaeus L.) was limited and not enhanced when picloram was added to the application solution. Translocation of 2,4,5-T in 6-month-old cuttings after treatment of a single spine or lateral branch was poor. The most significant accumulation of translocated herbicide occurred in stem tissue, with lesser amounts detected in root tissues, root nodules, stem apices and flowers. Untreated lateral branches or spines accumulated minimal amounts of herbicide. The pattern and extent of distribution of 2,4,5-T was not increased by addition of picloram. The lack of efficient control of gorse by 2,4,5-T can largely be attributed to its inadequate uptake and lack of true systemic translocation.     

The preferential accumulation of picloram at sites of active growth in gorse (Ulex europaeus L.)

Application of ¹⁴C-picloram to single spines of 6 month old, soil grown, vegetative plants of gorse (Ulex europaeus L.) resulted in its translocation to regions of meristematic and metabolic activity, with significant accumulation in the stem apex and root nodules. Dissection of the root system of plants grown in nutrient solution revealed a greater mass of picloram in differentiated root tissue than in root apices, although the concentration of chemical in the latter fraction was greater than in the former. Loss of picloram to the nutrient solution was interpreted as preferential leakage from the root nodules because of the lack of picloram accumulation in this fraction. In reproductive plants bearing flowers and floral buds the picloram was diverted from the root tissue fractions to the floral organs, which constituted the primary sink.