Abstract
The development of leaf succulence and the content of K, Ca, Mg, P, and N were measured in
the gesneriad Codonanthe macradenia J. D. SMITH, which grows as epiphyte in open sclerophyll forests
on white sands in the Amazon basin (upper Rio Negro basin), under a wide range of light exposures.
Leaves show a multiseriate adaxial epidermis occupying 35 % - 68 % of the total leaf thickness.
Succulence and epidermis thickness are linearly correlated with the amount of K per unit leaf area,
resulting in a nearly constant K concentration per unit tissue water. Both K and P are more concentrated in the epidermis than in the underlying photosynthetic tissue. Succulence and K accumulation
appears to be associated to N deficiency during leaf development. Succulence in this species may play
an ecological role as a drought endurance mechanism.
