The overall goal of this research is to understand the structure and function of plant salt glands. These studies will use transmission electron microscopy, freeze-fracture electron microscopy, X-ray microprobe studies, and morphometric procedures, as correlated with physiological experiments to assess the mechanisms involved in secretion and the structural and organizational features of the glands apparently requisite for glandular function. Assuming that membrane transport is the fundamental physiological process underlying salt secretion, the goal is to characterize, as well as is presently possible, the pertinent membranes of salt gland cells, particularly as to flux capacities, selective transport properties, effects of selective inhibitors, and their macromolecular organization as related to secretion. Since comparative ultrastructural studies of the different gland types have continued to advance our insight into the structural and functional relationships basic to the secretory processes in different types of plant glands, these comparative studies will be continued. Further, studies will be expanded to examine the organization of cells, organelles, cell compartments, and membranes in regard to absorptive processes. The proposed research is designed to clarify the structural and functional relationships in plant glands relative to the processes of secretion and absorption and to determine the macromolecular organization of the cell membranes of plant secretory cells. Salt glands occur in the leaves of a wide variety of higher plants and are believed to be important in the regulation of the ionic balance of leaves. The results of this research will contribute to our understanding of the structure and function of these important plant organs.
