Factors Affecting Pigment Levels During Re-Greening of Valencia Orange |
| |
| Authors: | B M El-Zeftawi |
| |
| Institution: | Mildura Horticultural Research Station, P.O. Box 460, Irymple, Victoria, Australia 3498 |
| |
| Abstract: | Seasonal changes in pigment levels were found to coincide with five colouring stages: green, colouring, orange, yellowing and re-greening. The changes in pigment levels mainly causing re-greening are a result of a reduction in carotenoids and an increase in chlorophyll levels after the carotenoids reach their maximum and the chlorophylls their minimum levels during the orange stage. More chlorophyll a than b occurs while the fruit is green, but it starts to fall below the chlorophyll b level during the colouring stage and thereafter. This happens in the re-greening cultivars of Citrus sinensis such as Valencia and Lane Late Navel oranges, but not in the non-re-greening cultivars such as Leng and Washington Navels. These changes in pigment levels appear to be related to increasing-light intensities during spring and summer and to hormonal control from seeds and/or the rootstock. |
| |
| Keywords: | |
|
|
