This work aimed at evaluating the carbohydrate content of one 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 (04/19, 05/10, 05/31, 06/21, 07/12, 08/02 and 08/23) and were treated or not with 1,440 hours of chill (4 to 7° C). The carbohydrates were analysed in buds and stem tissues close to the buds. The soluble carbohydrates (SC) were evaluated by the phenol-sulfuric acid method and the final determination was made by spectrophotometry (490 nm absorbance). The non-soluble carbohydrates (NC) were estimated by the mass of vegetal tissues non-soluble in alcohol and soluble in alcaline medium, after freeze drying. The total carbohydrate (SC + NC) content represented 13.8 to 20.2 g.100g-1 of dry matter of buds and 9.9 to 15.3 g.100g-1 of dry matter of stems. The buds presented a higher level of SC in the initial dormancy period and a higher level of NC in the more intense dormancy period. The NC accumulation in buds were anticipated by the early chill treatment and the chill treatment during endodormancy promoted the SC accumulation. The SC content in stems increased along the dormancy development while the NC content remained constant.
Malus domestica Borkh; Imperial Gala; physiology; dormancy
