
%0 Journal Article
%A P&eacute;rez, Francisco J. 
%A Morales, Ver&oacute;nica 
%T A basic peroxidase isoenzyme from the grape pedicel is induced by gibberellic acid
%J Functional Plant Biology
%D 1999/07/29
%V 26
%N 4
%P 387-390
%K 
%R https://doi.org/10.1071/PP98127
%U https://www.publish.csiro.au/paper/PP98127 
%X Soluble peroxidase activity from pedicels of seedless table grape cv. Sultana was highly stimulated by post-bloom applications of gibberellic acid (GA3) to vines. The increase in peroxidase activity was mainly due to the induction of a basic peroxidase isoenzyme (pI &#62; 9; BPrx-HpI). The activity of two other peroxidase isoenzymes of pI 6.5 and 3.2 was not altered by the hormone treatment. BPrx-HpI was induced by GA3 in pedicels and rachis but not in berries, although in berries peroxidase activity was also stimulated by post-bloom GA3 applications. BPrx-HpI oxidised guaiacol and ortho-phenylenediamine (o-PDA), while the others peroxidases found in the pedicel and in the berry oxidised only o-PDA. Hence, BPrx-HpI was characterised as a guaiacol-peroxidase showing no activity towards ascorbic acid (ASC). The possible role of BPrx-HpI in pedicel lignification and berry-drop caused by GA3 applications to cv. Sultana vines is discussed. 
