Ultrastructural effects of formulated picloram on leaflets of velvet mesquite and catclaw acacia*

Abstract

Summary: The effects of picloram formulated with a nonionic surfactant (X‐77) and of the surfactant alone on the ultrastructure of leaf cells of velvet mesquite (Prosopis velutina Woot.) and catclaw [Acacia greggii var. ariznica (Gray) Isely] were examined The surfactant induced temporary protrusions from chloroplasts in both species. A proliferation of rough endoplasmic reticulum (RER) was noted in velvet mesquite within 8h of application of the herbicide and in catclaw with in 27 h. By 72h after treatment. both species exhibited distortions of organelles with more severe symptoms in catclaw. the species more sensitive to the herbicide Leaf abscission occurred subsequently and was more pronounced in catclaw than in mesquitel It is known that RER proliferation is induced by ethylene and that ethylene evolution is stimulated by picloram. The present study suggests that the interaction between these two chemicals was similar in the two plant species studied.

Physiological and ultrastructural changes in Stellaria media following treatment with fluroxypyr

“…Bretherton & Hallam (1979) associated a similar sequence of ultrastructural changes in 2,4,5-T treated Rubus procerus with an acceleration of the normal structural changes associated with senescence (Butler & Simon, 1971). Increases in the levels of rough endoplasmic reticulum have been reported in auxin herbicide-treated leaves (Bleckman, Hull & Morton, 1979) but were not detected in fluroxypyr-treated S . media leaves.…”