Dynamics of Starch Reserves in Some Grapevine Varieties (Vitis vinifera L.) During Dormancy

Carbohydrate reserves in grapevine are stored in form of starch and soluble sugars. The present study was conducted in order to understand the dynamics of insoluble carbohydrate reserves during dormancy season of some table and wines grapevine varieties. Six year old grapevine varieties (Muscat de Hamburg, Napoca, Cardinal, Perla de Csaba, Fetească regală, Muscat Ottonel, Pinot noir and Fetească neagră) were sampled before winter. During dormancy, starch level in canes was appreciated by iodin in potassium iodide method, wood and pith diameter measured and bud viability tested. The levels of starch in grape canes at the beginning of dormancy (November) was highest in Muscat de Hamburg (3.89), Napoca and Fetească regală (3.76) and the lowest in Cardinal (3.47). Due to climatic conditions over dormancy, starch began to resynthesize already during January and February, with significantly high levels for all varieties. Wood/pith ratio was highly correlated with starch level. Bud viability was directly influenced by the starch level in canes