Salt Hypertrophy in Succulent Dune Plants

Abstract

An investigation of the type of succulence found in dune plants growing on non-saline soils near the strand. Typically these dune plants are characterized by thick, succulent leaves on the windward (ocean) side, and thin, less-succulent, often coriaceous leaves on the leeward (shore) side of the same plant. Oiled glass slides exposed in different positions on a shrub of Iva imbricata showed that the leaves on the windward side caught on the average at least four times as much salt spray as leaves on the leeward side. Correlated anatomical studies revealed that the swelling of the non-chlorenchymous parenchyma cells accounted for the succulence of the "windward" leaves; the swelling action of these cells was the result of salt accumulation in the vacuoles causing an increase in turgor pressure and a concomitant expansion of the cell walls.