Nucleotide synthesis capability as a marker of the petiole elongation of strawberry plants (Fragaria 3 ananassa Duch.)

Vegetative growth of strawberry plants, estimated by leaf blade and petiole sizes, influences fruit development notably through carbohydrate synthesis . Improvement in fruit production requires the control of internal and exte rnal vegetative growth factors. For a better knowledge of the internal caus es of vegetative growth, we evaluated cell elongation, cell size and cell n umber in petioles of 'Elsanta' strawberry plants observed under natural con ditions. Nucleotide synthesis potentialities of these petioles were also me asured as well as adenosine kinase activity, an enzyme of the nucleotide me tabolism. A growth area near the leaf blade was identified by these measure ments. At the cellular level, elongation of petioles was a concomitant effe ct of size increase and multiplication of cells which primarily took place in the upper part of the petiole. Synthesis capabilities of nucleotide and adenosine kinase activity were high at the beginning of petiole growth, whe n cell development was important. The correlation established between these morphological and biochemical measurements suggest that the measurement of nucleotide synthesis potentialities and adenosine kinase activity could be used as markers for vegetative growth of strawberry plants.