ABSTRACT
This chapter focuses on the physiological characteristics and metabolism of assimilate partitioning and source-sink relationships in cucurbits. It reviews carbohydrate metabolism in the cucurbit sink with emphasis on those aspects of metabolism that impact on assimilate partitioning and particularly with respect to sucrose synthesis and accumulation. Plant growth habit and plant density also greatly affect the canopy structure and subsequent light distribution in the plant canopy, and whole plant photosynthesis is greatly affected by these factors. In cucurbits, in contrast to the more well-studied sucrose-translocating plants, still relatively little is known concerning the control of carbon partitioning between storage and mobile pools of photoassimilates. In these areas, CO2 enrichment of the atmosphere is practiced on a commercial scale to enhance yield of greenhouse-grown slicer-type cucumbers and other vegetables, particularly tomatoes. The adaxial phloem of the seventh order veins has a structure and morphologic features more characteristic of phloem from most other plant species and plant parts.
