SHST - Horticulture and Forestry Society from Transylvania, 40 Years of Horticulture Education in Cluj-Napoca

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Daily Dynamics of Sugar and Phenol Contents in Apple Fruitlets (Malus domestica Borkh.) during June Drop

Last modified: 2017-04-15


Apple tree (Malus domestica) is a good model plant to study the occurrence of the abscission signal in young developing fruits.  It has a natural system of fruitlet shedding, so called June drop. Although, the physiological fruit drop is not able to guarantee production of marketable apples and avoid alternate bearing, knowledge of this is a key background for successful fruit thinning. A two year study was carried out on apple trees cv. ‘Golden Delicious’ during June drop. In three dates (beginning, middle and after June drop) a daily dynamics of HPLC detected individual sugar and spectrophotometrically detected total phenolic contents was investigated in central (K) and lateral (L) fruitlets. Results of daily dynamic showed the highest sugar contents at 2 p.m. On the final sampling date, on the 2nd of July 2015, we observed a significant difference among sugar contents at 2 p.m. and the morning and afternoon measurements. Contents of sugars in K and L fruitlets were not significantly different. Total phenolic content at the beginning of June drop was higher than at the end. Between K and L in a specific time period there was no statistically significant difference, while among the sampling dates were statistically significant differences in total phenolic content. Although sugar and phenolic contents in K and L fruitlets were rarely statistically different, their contents changes during of June drop. In general, sugar contents increased and phenolic contents decreased during the process, while daily dynamic depended on weather conditions.



This abstract was accepted to be presented at the conference entitled “40 Years of Horticulture Education in Cluj-Napoca” Cluj-Napoca, September 27, 2017, being included in ‘Book of Abstracts’ of this special-anniversary event ( All accepted papers will be published in a special issue of Notulae Botanicae Horti Agrobotanici Cluj-Napoca journal.