Effect of fruit load on maturity and carotenoid content of clementine (Citrus clementina Hort. ex Tan.) fruits

Abstract

Taken together, the results do not support the common view that carbohydrate availability directly determines carotenoid synthesis by influencing precursor availability.

Biochemical bases and molecular regulation of pigmentation in the peel of Citrus fruit

“…However, manipulation of the sugar status in the peel of Clementine mandarins by shading or defoliation produced an enhancement of carotenoid content in the peel but did not affect or reduce carbohydrate concentration (Poiroux-Gonord et al, 2012). These authors suggest that carbohydrates supply is not a limitation for carotenoids biosynthesis, rather their availability at the end of the cell enlargement phase or early maturation may provide a signal for carotenoid regulation and that carbohydrate starvation promotes carotenoid accumulation (Poiroux-Gonord et al, 2012). Whether these assumptions based on stress-induced (shading or defoliation) carbohydrate changes would reflect the natural occurring interaction between sugars and carotenoid in the peel of Citrus fruits remains to be determined.…”

“…Sucrose-induced colour changes have been observed to be mediated by the action of ethylene and the effect of gibberellins delaying colour changes may be due by altering the sugar-ethylene interaction. However, manipulation of the sugar status in the peel of Clementine mandarins by shading or defoliation produced an enhancement of carotenoid content in the peel but did not affect or reduce carbohydrate concentration (Poiroux-Gonord et al, 2012). These authors suggest that carbohydrates supply is not a limitation for carotenoids biosynthesis, rather their availability at the end of the cell enlargement phase or early maturation may provide a signal for carotenoid regulation and that carbohydrate starvation promotes carotenoid accumulation (Poiroux-Gonord et al, 2012).…”

Short‐ and long‐term effects of carbohydrate limitation on sugar and organic acid accumulation during mandarin fruit growth

“…All girdled fruiting shoots had only one fruit and 30 leaves at the beginning of the trial. The 30 leaf‐to‐fruit ratio corresponds to conditions of non‐limiting carbon availability and was considered as the control condition . We checked that no phloem connection formed again after girdling.…”

Carotenoid responses to environmental stimuli: integrating redox and carbon controls into a fruit model

“…Similarly, low carbohydrate availability during fruit development irreversibly promotes carotenoid accumulation (Poiroux‐Gonord et al . ). In the latter study, all fruits had reached the same final stage of maturity, and thus the measurements were not biased by the process of fruit development.…”