Physico-Chemical and Physiological Changes during Fruit Development and Ripening of Five Loquat (Eriobotrya Japonica Lindl.) Cultivars

Abstract

Physico-chemical and physiological changes during development and ripening of five loquat cultivars ( Eriobotrya japonica Lindl., cv. Algerie, Cardona, Golden, Magdall and Peluche) were determined. Fruit growth showed a sigmoid curve in all loquat cultivars. A good relationship between duration of fast growth phase and fruit size was found. In addition, a positive correlation was also established between seed number and fruit size, and between seed weight and both fruit and flesh weight. Colour changes, sugar content increase and the decrease in fruit firmness and organic acids started simultaneously when loquat fruits were in the phase of fast growth, and at about 70-80% of their final weight. These physico-chemical changes related to fruit ripening coincided with an increase in both ethylene production rate and free and total 1-aminocyclopropane-1 -carboxylic acid (ACC) content in the flesh. In addition, a small respiration peak associated with ripening was also detected. These results indicated that loquat fruits of all five studied cultivars showed a pattern of ripening in the tree that could be classified as climacteric, with relatively low ethylene production evolving at an early phase of fruit development.

Ethylene, Enzymatic and Respiratory Pattern Evolution in Loquat (Eriobotrya japonica (Thunb.) Lindl.) cv. Golden Nugget in the Last four Sequential Stages of Maturation

“…These results are contrary to those of Hirai (1980;1982); ; Amorós et al (2003), who found a significant, though slight, increase in the respiratory rate at color break. The situation with ethylene is quite different, as here a significant increase in concentration was observed as the fruit changed color from green to color break, which continues until yellow, before finally falling.…”

“…The maturity stages of color break (BBCH 805) and yellow (BBCH 807) present similar characteristics in terms of fruit quality (Table1), which may be because color development is primarily initiated by chlorophyll degradation, which in turn leads to an increase in the luminosity of the fruit without increasing color intensity (Amorós et al, 2003) or sugar and acid content. Only the subsequent formation of β-carotene and cryptoxanthin gives the fruit its final orange color (BBCH 809) .…”

“…This result is in agreement with Gariglio et al (2002), who reported that fructose represents 15 to 33% of the total sugar in the initial stages of fruit growth, and during color change it increases three times. Similarly, Amorós et al (2003) found that in the color break stage of cv. Golden Nugget, sucrose increases sharply, before the initiation of the increase in glucose and fructose.…”

“…Another important acid is citric, which remains constant throughout fruit development (Uchino et al, 1994;Ding et al, 1998a;Lin et al, 1999;Amorós et al, 2003).…”

“…However, some authors have found a rise in respiration and in ethylene generation during the last period of fruit growth and development, thus assigning climacteric behavior and at the same time causing controversy with regards to its true respiratory pattern (Hirai, 1980;1982;Amorós et al, 2003;Cortés 2003). Christoffersen et al (1982) studying avocado (Persea americana Mill.)…”