Sugar import and metabolism during seed development

• Published in: Trends in plant science Vol. 2; no. 5; pp. 169 - 174
• Main Authors: Weber, Hans, Borisjuk, Ljudmilla, Wobus, Ulrich
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.1997; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; cell differentiation; cell division; cell growth; developmental stages; Economic plant physiology; Fabaceae; Fructification and ripening; Fructification, ripening. Postharvest physiology; Fundamental and applied biological sciences. Psychology; Growth and development; metabolism; nutrient transport; plant anatomy; Plant physiology and development; Poaceae; seed development; sugars; Vegetative and sexual reproduction, floral biology, fructification; Translocation; Leguminosae; Dicotyledones; Seed; Angiospermae; Spermatophyta; Carbohydrate; Developmental stage; Review; Metabolism; Source sink relationship
• ISSN: 1360-1385; 1878-4372
• DOI: 10.1016/S1360-1385(97)85222-3

During seed development, cell division is followed by elongation, differentiation and storage. In legumes, this sequence of events has been found to spread in a wave-like manner, creating a developmental gradient across the cotyledons. All these processes, including storage activities, appear to be subject to metabolic control. Sucrose is imported during seed development, and a sucrose breakdown pathway mediated by cell wall invertase operates in the seed coat during early development. The resulting high hexose state is associated with growth and mitotic activity. The storage/maturation phase is initiated following the developmentally controlled loss of invertase, and is accompanied by the formation of an active sucrose transport system. Invertases are therefore regarded as a control element in the changing carbohydrate status of seeds, and the invertase control hypothesis for seed development has emerged. Cotyledonary sucrose metabolism is controlled by a cycle of synthesis and breakdown involving sucrose-phosphate synthase and sucrose synthase, respectively; net breakdown for storage product synthesis involves sucrose synthase. The complex framework of interactions involved in these pathways is now being elucidated via a combination of biochemical, physiological and molecular methods.