Anatomical and physico-chemical characteristics of fruits of apple trees (Malus domestica Borkh.) and their relations to lenticel breakdown / Características anatômicas e físico-químicas de frutos de macieira (Malus domestica Borkh.) e sua relação com a lenticelose




The aim of this study was to describe anatomical and physico-chemical characteristics of apple fruits (Malus domestica Borkh.) Gala and Galaxy grown in three different altitudes, seeking to correlate them to the physiological disorder known as lenticelose (lenticel breakdown), characterized by the darkening of lenticels and the occurrence of brownish depressions around them. Mature fruits were harvested in 2008-09, from commercial orchards located in each of three producing areas: Vacaria (RS), Fraiburgo (SC) and São Joaquim (SC), located at 971, 3.088 and 1.353 m altitude, respectively. The evaluations were realized in the mature, freshly harvested fruits and during the storage, when the fruits were subjected to two distinct conditions: refrigeration (0ºC and 90% HU) and controlled atmosphere (1.5% O2; CO2; 2.5%, 0ºC and 90% HU). The fruits were evaluated anatomically at the harvest moment and during storage, when any physiological disorder related to lenticels was detected. The surface of the mature fruit of apple Gala and Galaxy freshly harvested from the three localities and at the end of the storage period in the studied conditions were examined under scanning electron microscope to compare the deposition of epicuticular waxes. Additionally, the fruits were evaluated at every 30 days, during storage, in relation to lenticels dyeing test (number) and to the following qualitative attributes: color, firmness, index of ripening, soluble solids content, titratable acidity and physiological disorders. In order to characterize the formation of different types of lenticels, the anatomical structure of fruits, collected in Vacaria (RS), it was also analyzed in different stages of development. There were no differences in the pattern of formation of lenticels between Galaand Galaxyand the producing areas. Fruits with lenticel breakdownsymptoms had a surface depression as a result of the obliteration of the epidermal and sub epidermal cells, and the underlying parenchyma exhibited large spaces formed by cell lyses. The symptomatic area was not always associated to the presence of lenticels. The results showed that the altitude did not affect the cuticular thickness or the pattern of deposition of epicuticular waxes in apple fruits of Galaand Galaxy. In freshly harvested fruits it was observed the deposition of wax platelets and the mechanism named Tear and Repair or Rip and Stitch". After four months of storage, we observed changes in the shape of the waxes from platelets to spherical or amorphous clusters in fruits of Galaand Galaxy from all producing areas. The changes were most evident in controlled atmosphere storage condition. There were no significant differences between the two storage conditions and the onset of symptoms in fruits from the three producing areas in relation to the physico-chemical parameters. The highest incidence of symptoms occurred in fruit Galafrom São Joaquim (SC) at the end of the storage period.


galaxy. distúrbios fisiológicos de plantas anatomia vegetal gala waxy anatomy lenticels maça - armazenagem.

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