Behaviour of Herbicides in Dicotyledonous Roots Transformed byAgrobacterium rhizogenes

Mugnier, J. 1988. Behaviour of herbicides in dicotyledonous roots transformed by Agrobacterium rhizogenes. II. Transport to regenerated shoots.—J. exp. Bot. 39: 1057–1064. Regenerated plants from roots of Anagallis arvensis transformed by Agrobacterium rhizogenes were propagated in Petri dishes on Murashige and Skoog's medium. The roots were exposed to different herbicides. We report here the relationship between root uptake and translocation of the herbicides acting upon the shoots. The results show that regenerated Anagallis arvensis plants propagated in Petri dishes reflected the situation in normal plants in their responses to symplastic herbicides (aminotriazole, glyphosate, 2,4-D) which have strong bleaching or wilting effects. Sucrose seemed to be the critical driving force by which symplastic herbicides were transported from the root towards the shoot. The results applied to a limited range of environmental conditions since the transport and performance of apoplastic herbicides (S-triazines, triazinones, substituted ureas) was apparently limited by the sucrose and moisture conditions in the Petri dish. The mode of transport, in phloem versus xylem, of herbicide within a transformed root is discussed.