Author:

Abstract:

In plants with crassulacean acid metabolism (CAM), carbohydrate availability is a major limiting factor for nocturnal CO2 uptake. In several model CAM species, starch is degraded at night to provide phosphoenolpyruvate as substrate for PEPC. The nocturnal requirement for PEP represents an additional sink for carbohydrate that must be reconciled alongside the carbohydrate demands imposed by growth and maintenance processes. This presentation considers whether or not the specialized requirement for carbohydrate in CAM plants is reflected by a‘re-engineering’ of carbohydrate processing compared to that in C3 plants, both in terms of regulation and the engagement of alternative metabolic pathways for carbohydrate breakdown. Data will be presented which indicates that leaf starch is degraded via a different route in Kalanchoë fedschenkoi compared to that in Arabidopsis. Findings will be discussed in line with the specialized metabolic requirements of CAM and the implications for carbon and water balance will be considered. Future areas of research allied to this topic will be highlighted.