This work aimed to quantify the variation of carbohydrate content in two year old buds and stems of apple trees cv. 'Imperial Gala' with or without supplementary chill during autumn and winter, cultivated in a region of low chill occurence. The stems were collected in Porto Amazonas, Parana State, Brazil, at intervals of 21 days from April to August (April 19th, May 10th, May 31st, June 21st, July 12th, August 2nd and August 23rd) and were either treated or not with 1,440 hours of chill (4 to 7° C). The carbohydrates were analysed in buds and stem tissues adjacent to the buds. The soluble carbohydrates (SC) were evaluated by the phenol-sulfuric acid method and the final determination was achieved by spectrophotometry (490 nm absorbency). The non-soluble carbohydrates (NC) were estimated by the mass of vegetal tissues insoluble in alcohol and soluble in alcaline medium, after freeze drying. Significant variations of carbohydrate content were observed in the two year old buds and stems during the dormancy. The increase of dormancy intensity in autumn is associated with the reduction of SC content in buds. The treatment with 1,440 hours of chill modify the variations of SC content in stems and NC content in buds.
Malus domestica Borkh.; 'Imperial Gala'; physiology; dormancy
