
TY  - JOUR
A1  - Svanella, L. 
A1  - Gaudill&egrave;re, M. 
A1  - Gaudill&egrave;re, J. P. 
A1  - Moing, A. 
A1  - Monet, R. 
T1  - Organic acid concentration is little controlled by phospho<emph type="2">enol</emph>pyruvate carboxylase activity in peach fruit
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1999
VL  - 26
IS  - 6
SP  - 579
EP  - 585
KW  - amino acids, citric acid, 14C labelling, malic acid, Prunus persica.
UR  - https://doi.org/10.1071/PP98164 
N2  - Changes in phosphoenolpyruvate carboxylase (PEPC) activity were studied during the fruit development of two peach cultivars (Prunus persica (L.) Batsch) with normal (&#8216;Fantasia&#8217;) and low (&#8216;Jalousia&#8217;) organic acid concentration. PEPC activities were measured in fruit mesocarp at two stages of development, corresponding to malate accumulation and citrate accumulation phases in &#8216;Fantasia&#8217;, respectively. In vitro activity, measured under optimal conditions, was significantly higher in &#8216;Fantasia&#8217; than in &#8216;Jalousia&#8217; during the malate accumulation phase but lower during the citrate accumulation phase. In vivo activity was estimated using 14CO2 labelling. The total incorporated radioactivity was higher in &#8216;Fantasia&#8217; than in &#8216;Jalousia&#8217; during the malate accumulation phase but lower during the citrate accumulation phase. During the malate accumulation phase, the partitioning of incorporated 14C into malate was significantly reduced in &#8216;Jalousia&#8217; compared to &#8216;Fantasia&#8217; after 20 min labelling. During the citrate accumulation phase, 14 C partitioning into malate was not significantly different between varieties, but partitioning into citrate was significantly reduced in &#8216;Jalousia&#8217; compared to &#8216;Fantasia&#8217;. Therefore, PEPC activity does not seem to be the controlling step for the absence of organic acid accumulation in &#8216;Jalousia&#8217; fruit. The other metabolic causes of the difference in organic acid accumulation are discussed; these may be connected with vacuolar storage. 
ER  -

