Author(s):
Elias, Elsa 
; Silva, Anabela Bernardes da ; Antunes, Rosário ; Silva, Jorge Marques da
Date: 2010
Persistent ID: http://hdl.handle.net/10400.1/2904
Origin: Sapientia - Universidade do Algarve
Subject(s): Chlorophyll fluorescence; Fruit ripening; Orchard irrigation regime; Shelf-life
Description
Proceedings of the International Conference “Environmentally friendly and safe technologies for quality of fruit and vegetables”, held in Universidade do Algarve, Faro,Portugal, on January 14-16, 2009. This Conference was a join activity with COST Action 924 The effect of the orchard irrigation regime on the on-shelf ripening of Pyrus communis L. var. ‘Rocha’
fruit was studied and the use of chlorophyll a fluorescence as a tool to assess the maturation of fruit was
evaluated. Minimal (Fo) and maximal (Fm) fluorescence and maximal photochemical efficiency of PSII
reaction centers (Fv/Fm) were measured in pear grown in irrigated (Ir) and non-irrigated (NIr) orchards and
stored for two months in cold under normal atmospheric conditions, after which fruits were removed from
the refrigerated chambers and held at room temperature (approx. 20 ºC) for 14 days (d). Measurements
were made on the day of removal from refrigerated storage (t=0) and after 4, 7, 10 and 14 d at 20 ºC. Total
chlorophyll content (Chl a+b) of pears skin was measured as well as the pulp firmness and the total content
of soluble solids (SSC). At 0 d at room temperature, Ir fruit, although with a lower chlorophyll content, was
firmer than NIr fruit but after 14 d at room temperature no differences were observed between them. No
significant differences were generally observed in SSC either between Ir and NIr fruit or during ripening.
All fluorescence parameters decreased in Ir and NIr fruit, with Fo and Fv/Fm lower in Ir fruit after 2 months
of cold storage while in Fm no significant differences were observed between the irrigation treatments.
The correlation of firmness and chlorophyll content with SSC was always weak in both irrigation regimes.
In contrast, the correlation between firmness and chlorophyll content was always strong as well as the
relationship between firmness and the fluorescence parameters. The maximal fluorescence (Fm) was the
parameter that had the best correlation with fruit firmness. The irrigation regimes applied to ‘Rocha’ pear
orchards seems to influence the ripening of ‘Rocha’ pear fruit with a more steeply ripening of the fruit
grown in irrigated orchards characterized by a greater loss of firmness and chlorophyll fluorescence.
