02514nam a2200361 a 450000100080000000500110000800800410001910000230006024501660008326000390024930000090028850000230029752015320032065000220185265000210187465000230189565000140191865000230193265000160195565000170197165000150198865000100200365000140201365000100202765000290203765000130206665300140207965300110209365300090210465300100211365300140212365300150213714744152019-11-25       1997    bl uuuu  m   00u1 u    #d1 aSOUZA, I. R. P. de  aGibberellic acid and dwarfism effects on peroxidase activity and secretion of anionic isoenzymes into the cell wall of expanding maize (Zea mays L.) leaf blades.  aLogan: Utah State Universityc1997  a89p.  aDoctor Sc. Thesis.  aMany studies have related changes in plant growth with peroxidase activity, but few of these have correlated changes in growth with changes in a specific isoenzyme, although many isoenzymes have been shown to be organ-specific with developmental expression. We used the developmental gradient presented by the maize (Zea mays L.) leaf blade to study the spatial distribution of growth and peroxidase activity. All experimentation used the second expanding true leaf blade in which the ligule ahd not been displaced from the leaf base by growth of the leaf sheath. Quantitative and qualitative analyses of total soluble (soluble plus ionically bound to the cell wall) and apoplastic peroxidase activity were conducted along the leaf blade of the B73 maize inbred line. For apoplastic fluid extraction, a vacuum-infiltration procedure was used followed by low-speed centrifugation. No cytoplasmic contamination occurred because no glucuose-6-phosphate dehydrogenase activity could be detected in apoplastic extracts. Total soluble peroxidase activity presented was high near the leaf base in the region of cell division, and relatively low through the rest of the elongation zone. In contrast, a transient peak in apoplastic peroxidase activity occurred in the middle of the elongation zone, ans poceded a arpid decrease in cell elongation rate. Zymograms of total and apoplastic extraction showed that two anionic peroxidase isoenzymes, pI 5.6 and 5.7 began to increase in activity where epidermal cell elongation stopped. (...)  amolecular biology  aplant physiology  aÁcido Giberélico  aAlumínio  aBiologia Molecular  aCrescimento  aEletroforese  aFisiologia  aFolha  aIsoenzima  aMilho  aRegulador de Crescimento  aZea Mays  aAluminium  aGrowth  aLeaf  aMaize  aTolerance  aTolerancia