%0 Journal Article
%T Influence de l\'acide salicylique sur la synth¨¨se de la ph¨¦nylalanine ammonia-lyase, des polyph¨¦noloxydases et l\'accumulation des composes ph¨¦noliques chez le manioc (Manihot esculenta Crantz)
%A DO Dogbo
%A JAM Bekro
%A YA Bekro
%A RS Sie
%A SJ Gogbeu
%A A Traore
%J Sciences & Nature
%D 2008
%I 
%X Pour ¨¦tudier la r¨¦action de d¨¦fense du manioc contre les agents pathog¨¨nes, nous avons ¨¦valu¨¦ l'activit¨¦ de la ph¨¦nylalanine ammonia-lyase (PAL) et des polyph¨¦noloxydases (PPO), et dos¨¦ les compos¨¦s ph¨¦noliques totaux ¨¦thano-solubles accumul¨¦s avant et apr¨¨s l'inoculation de l'acide salicylique (AS) dans des plants ag¨¦s de six semaines. La synth¨¨se des enzymes a ¨¦t¨¦ pr¨¦cocement induite (1-4 h). L'activit¨¦ de la PAL a ¨¦t¨¦ 4 ¨¤ 13 fois stimul¨¦e et celle des PPO, 3 ¨¤ 11 fois plus, selon les cultivars. Les taux de compos¨¦s ph¨¦noliques totaux ¨¦thano-solubles ont subi une augmentation significative d¨¨s l'inoculation des plantes. Ces taux sont rest¨¦s quasi constants malgr¨¦ la baisse de l'activit¨¦ de la PAL. La synth¨¨se de l'enzyme a ¨¦t¨¦ ¨¦galement stimul¨¦e dans les feuilles imm¨¦diatement situ¨¦es audessus (fis) et en dessous (fii) de la feuille inocul¨¦e (fi). Les compos¨¦s ph¨¦noliques ont subi aussi une augmentation dans ces feuilles. Concernant l'age de la feuille inocul¨¦e (4 et 6 semaines), la synth¨¨se de la PAL et la quantit¨¦ des compos¨¦s ph¨¦noliques ont ¨¦t¨¦ plus ¨¦lev¨¦es dans les feuilles adultes. To study the reaction of defence of cassava against pathogens, we have evaluated the activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidases (PPO) and dosed total ethano-soluble phenolic compounds accumulated before and after inoculation of salicylic acid in six weeks old seedlings. Enzymes synthesis was precociously induced (1¨C4 h). PAL activity was 4 to 13 times stimulated and those PPO, 3 to 11 fold higher, according to varieties. Dosed total phenolic compounds undergone a significant increase since the plants inoculation, and this rate has remained almost constant despite the decrease of PAL activity. The enzyme synthesis was equally stimulated in immediately situated leaves above (fis) and in under (fii) of the inoculated leaf (fi). Phenolic compounds have also undergone an increase in these leaves. Concerning the age of the inoculated leaf (4 and 6 weeks), the PAL synthesis and the phenolic compounds quantity have become more important in adult leaves.
%U http://www.ajol.info/index.php/scinat/article/view/42147