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Chlorfenprop-methyl (the herbicidal component of BIDISIN®), and to a lesser extent the free acid, chlorfenprop, inhibit auxin mediated cell responses in coleoptiles of Avena sativa L. and Zea mays L., such as cell elongation, auxin-uptake, -transport and -metabolism, acidification of growth media, and binding of naphthyl-1-acetic acid to auxin-specific binding sites in homogenates of corn coleoptiles. Within a very narrow concentration range (1 to 2μM) chlorfenprop-methyl arrests growth from 0 to 100% in sensitive cultivars. The compound displays neither auxin- nor anti-auxin-activity, and only the L(-)-enantiomer is active. The interaction of the herbicide with auxin at the level of membranes is proposed. [ABSTRACT FROM AUTHOR]

During the early development of mungbean seedlings, treatment with L-α-aminooxy-β-phenylpropionic acid (AOPP), a potent specific inhibitor of phenylalanine ammonia-lyase, results in an inhibition of anthocyanin and lignin synthesis. The xylem vessels of the hypocotyl and root of AOPP treated seedlings collapse, and the cellulose microfibrils of the unlignified secondary wall are separated from one another and lie disorganized in the lumen of the mature xylem cell. The differentiation of the secondary cell wall appears unaffected by AOPP treatment, as does the ultrastructure of the wall of the mature phloem fibers of the root which is also lignified in untreated tissue. The results are discussed in the light of current thinking on the role and development of lignification in the xylem vessel. [ABSTRACT FROM AUTHOR]