Photocontrol of bud burst involves gibberellin biosynthesis in Rosa sp.

Light is a critical determinant of plant shape by controlling branching patterns and bud burst in many species. To gain insight into how light induces bud burst, we investigated whether its inductive effect in rose was related to gibberellin (GA) biosynthesis. In axillary buds of beheaded plants subject to light, the expression of two GA biosynthesis genes (RoGA20ox and RoGA3ox) was promptly and strongly induced, while that of a GA-catabolism genes (RoGA2ox) was reduced.

Insight into the role of sugars in bud burst under light in the rose.

Bud burst is a decisive process in plant architecture that requires light in Rosa sp. This light effect was correlated with stimulation of sugar transport and metabolism in favor of bud outgrowth. We investigated whether sugars could act as signaling entities in the light-mediated regulation of vacuolar invertases and bud burst.

Regulation of RhSUC2, a sucrose transporter, is correlated with the light control of bud burst in Rosa sp.

In roses, light is a central environmental factor controlling bud break and involves a stimulation of sugar metabolism. Very little is known about the role of sucrose transporters in the bud break process and its regulation by light. In this study, we show that sugar promotes rose bud break and that bud break is accompanied by an import of sucrose.

Sugars are under light control during bud burst in Rosa sp.

Bud burst in certain species is conditioned by the luminous environment. With roses, the requirement for light is absolute, and darkness totally inhibits bud burst. Few studies have looked into understanding the action of light on the physiological bud burst processes.

Evidence for apoplasmic phloem unloading in developing apple fruit.

The phloem unloading pathway remains unclear in fleshy fruits accumulating a high level of soluble sugars. A structural investigation in apple fruit (Malus domestica Borkh. cv Golden Delicious) showed that the sieve element-companion cell complex of the sepal bundles feeding the fruit flesh is symplasmically isolated over fruit development.