Phosphorylated and nucleotide sugar metabolism in relation to cell wall production in Avena coleoptiles treated with fluroride and peroxyacetyl nitrate

Abstract

Coleoptile sections of Avena sativa L. were pretreated with sodium fluoride or peroxyacetyl nitrate at levels which inhibit auxin-induced growth but did not affect glucose uptake or CO(2) production when postincubated for 30 minutes in a (14)C-glucose medium without auxin. Labeling of metabolites involved in cell wall synthesis was measured. Peroxyacetyl nitrate decreased labeling, and it was concluded that the pool size of uridine di-phosphoglucose, sucrose, and cell wall polysaccharides decreased compared to control. The changes suggest that peroxyacetyl nitrate inactivated sucrose and cell wall synthesizing enzymes including cellulose synthetase and decreased cell growth by inhibiting production of cell wall constituents. Fluoride treatment had no effect on production of cell wall polysaccharides, with or without indoleacetic acid stimulation of growth. The only change after fluoride treatment was a decrease in uridine diphosphoglucose during incubation without indoleacetic acid, a decrease that disappeared when indoleacetic acid was present. It was concluded that some other aspect of cell wall metabolism, not determined here, was involved in fluoride-induced inhibition of growth.