ULTRASTRUCTURAL OBSERVATIONS ON THE CUTICULAR ENVELOPE IN SALT-GLANDS OF FRANKENIA-PAUCIFLORA

During five developmental stages in differentiation of salt glands in leaves of Frankenia pauciflora, details of the deposition of incrusting material in the cuticular envelope, i.e., hydrophobic suberin and/or cutin, have been observed by means of transmission electron microscopy. Around each transfusion area in the cuticular envelope a conspicuous lamellate ring structure is found. Thin 3.5 nm lamellae associated with the plasmalemma around each ring structure appear to participate in the formation of tripartite structures showing a reversed contrast compared to the plasmalemma. Below the ring structure the cuticular envelope is divided into an outer fibrillar and an inner amorphous zone. A gradual transition between the tripartite lamellae of the ring structure and the amorphous material of the envelope is evident. Very dense material present between the lamellae appear to accumulate in the transition zone. The results are discussed in relation to basic structural features of various incrustations of lipid nature. © 1979 Springer-Verlag.