ISSN:
1432-2048
Keywords:
Auxin transport
;
Bisulfite
;
Cucurbita
;
N-1-Naphthylphthalamic-acid binding
;
Membrane vesicles
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The affinity of the auxin-transport inhibitor N-1-naphthylphthalamic acid (NPA) for membrane particles as well as for solubilized binding sites from Cucurbita pepo L. hypocotyls was reduced by low concentrations of bisulfite (half-maximal inhibition at 2·10-3–3·10-3 M). Two membrane fractions obtained by sedimentation aided with polyethylene glycol showed differential sensitivity to bisulfite. Other oxidizing or reducing substances tested at 1 mM had no effect, except for N-ethylmaleimide (80% inhibition) and iodine (complete inhibition), both of which reduced the number of binding sites but not their affinity. Addition of bisulfite to either the isoalloxane ring of flavoproteins or to pyridoxal phosphate or quinones is proposed as a possible mechanism of action. Sulfur dioxide, at concentrations measured in polluted air, can lead to bisulfite concentrations in plant tissue sufficient to interfere with NPA-binding sites and hence with auxin transport.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00395414
Permalink
