Succulent Photosynthetic Organs

Abstract

A succulent photosynthetic organ typically maintains positive daily carbon balance by having its own water reserve and accompanying high organ water potential. The organ possesses anatomical and physiological adaptations that yield very high WUE, even when it is severed from the root system (Nobel 1985,1988; Gibson and Nobel 1986). Succulence grades into “fleshiness,” which describes leaves having high water capacitance but wilting rapidly when a shoot is severed (Gibson 1982); fleshy organs lack many mechanisms of drought resistance and in warm deserts tend to be drought deciduous structures or occur on short-lived annuals. Therefore, succulence cannot be judged only by measuring the amount of stored water or thickness of the organ (von Willert et al. 1992).