Variation of Transhexadecenoic Acid Content in Two Triazine Resistant Mutants of Chenopodium album and Their Susceptible Progenitor.

Two atrazine resistant nutants of Chenopodium album L. and their susceptible progenitor were analyzed for lipid composition. In the phosphatidyldiacylglycerol the Delta3-trans-hexadecenoic acid (C16:1 trans) percentage was higher in the two resistant phenotypes. However, this difference appears later in the development of the leaves and is not clearly observed in young leaves and seedlings. Thus, the increase of the C16:1 trans during the leaf development of the resistant phenotypes is probably a secondary effect of the psbA mutation that arises in compensation for some photosynthesis deficiency. The significance of the lipid differences shown between the two resistant mutants is discussed in terms of whether they are responsible of the two different levels of herbicide resistance observed in the field.