Influence of the Post-Harvest Treatment with Calcium Salts upon the Quality of Apricot Fruit A. Chira and L. Chira U.S.A.M.V.Bd. Marasti, N° 59 Bucharest Romania V. Balan Research Station for Fruit Tree Growing Baneasa, Bd. Ion Ionescu de la Brad, N° 4 Bucharest Romania Keywords: Prunus armeniaca, immersion, tissue, permeability, firmness, respiration, ethylene synthesis Abstract Calcium plays an important role in maintaining the integrity of the cell wall and thus it influences the quality and the preservation of fruit. Staring from this aspect the present experiment was designed to assess the influence of some calcium salts treatments on the keeping of 3 Romanian cultivars: 'Comandor', 'Dacia' and 'Olimp'. Results revealed that the immersion in 2% Puracal had an inhibitory effect on respiration rate and ethylene synthesis and that it diminished the permeability of tissues. In the same time the calcium content and the firmness were higher than in untreated fruit. INTRODUCTION Being not very mobile in plant, calcium is an element of fruit quality and preservation. It is also present in the cellular wall and plays an essential part in maintaining its integrity. It reduces the risk of microclefts on the fruit epidermis and of internal browning which determines the main preservation defects (Labavitch et al., 1993). The calcium level in fruit depends on other minerals such as nitrogen, potassium and magnesium (Minamide et al., 1987). Due to its importance in maintaining the firmness of the pulp, an essential physical characteristic for the marketing of apricot, this research aimed at determining the influence of post-harvest calcium salts treatment on the preservation of the apricot. MATERIALS AND METHODS Fruit of the 'Dacia', 'Comandor' and 'Olimp' varieties were harvested at late ripening stade. Two calcium salts were used : calcium chloride (2% and 4%) and Puracal (1%, 2% and 3%). The later is the calcium salt of lactic acid produced by the fermentation of carbohydrates After harvesting fruit where dipped in the treatment solution for 30 minutes at 25°C. After drying they were kept at 4°C for 10 days and then at 20°C for 2 days so that maturation was complete. After few hours fruit treated with 2% or 4% calcium chloride and 3% Puracal showed phytotoxicity symptoms (brown necroses). Thus, experimental conditions selected were : V1 = 1% Puracal; V2 = 2% Puracal ; V3 = untreated control. At harvesting and at the end of the preservation period a series of physiological and biochemical analyses were performed in order to test the metabolic activity and some quality attributes of apricots. RESULTS AND DISCUSSION For the 'Comandor' variety (Table 1), produced by fruit. The treatment with 2% Puracal blocked the biosynthesis of this hormone. Ethylene was produced at a relatively high rate in fruit treated with 1% Puracal (36 ppm.h -1 ) and the highest rate was observed in the control (104 ppm.h -1 ). The ratio between the soluble dry matter and titratable acidity (an indicator of Proc. XII th Symposium on Apricot Ed.: J.M. Audergon Acta Hort. 701, ISHS 2006 571