Pigment and Ultrastructural Changes in the Developing Pummelo Citrus grandis 'Goliath'

Publisher Website
Google Scholar
Abstract
Pigment changes in the flavedo and endocarp of the developing pummelo, C. grandis ''Goliath,'' were investigated at 4 ripening stages; green, color break, almost ripe and fully ripe. In the flavedo, chlorophyll of the green fruit decreased abruptly and was totally absent in the fully ripe, lemon-yellow fruit, which contained only carotenoids. However, the total colored carotenoid content decreased from 26 .mu./g in the green fruit to 5 .mu.g/g in the fully ripe fruit. The pulp of the endocarp, characterized as colorless, contained small amounts of chlorophyll and 0.4 .mu./g total colored carotenoids which remained nearly at the same level in all ripening stages. The carotenoid pattern at the green stage of both the flavedo and the endocarp was that of the chloroplast type. During ripening, the four chloroplast carotenoids decreased gradually, and typical chromoplast carotenoids.sbd.such as .zeta.-carotene, neurosporene, mutatochrome, cryptoxanthin, and its 5,8-epoxide.sbd.appeared. The most striking phenomenon was the accumulation of large amounts of the colorless carotenoid precursor phytofluene, which amounted to 20 and 67% of the total carotenoids in the endocarp and flavedo, respectively. The ultrastructural changes of the flavedo plastids showed the gradual conversion of chloroplasts into chromoplasts. Two types of chromoplasts were formed: one contained only plastoglobules; the other, which predominated, also contained unusually long achlorophyllous membranes that were arranged in concentric circles.

This publication has 2 references indexed in Scilit: