Translocacion de fotosintatos en sarmientos de la vid durante el periodo vegetativo

Abstract

Translocation of photosynthate in grapevine shoots during the growth period

During 4 years, translocation of photosynthate was studied in shoots of three grape varieties supported with 3-wire trellis (2 m) andin five growth stages: pre-flowering, fruit set, prior to ripening, ripening and post-harvest. ¹⁴CO₂ was applied on the middle leaf of the basal, middle or apical third of the shoot, respectively (volume 200 ml under a plastic bag, 300 ppm of ¹⁴CO₂ of 3.7 x 106 Bq, 30 min, four shoots per variant). After 5 d, the radioactivity of the triturated tissues of the leaves of each third (excluding the treated leaf), of the clusters and of the growing tip was assayed in cpm/g in a Geiger Müller counter and dpm/mg of dry matter in a liquid scintillation counter. The maximum value of radioactivity within each shoot was taken as 100 % and all other data were related to it.
Photosynthate produced in the basal third of the shoot is always translocated to the cluster. The apical third does not export photosynthate. The cluster becomes the principal sink for photosynthate produced in the middle third of the shoot after fruit set, during its most intensive growth.