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Isotopen-Markierungen and Raster-elektronenmikroskopische Untersuchungen des Velameya radicum der Orchideen

1975; Elsevier BV; Volume: 75; Issue: 5 Linguagem: Inglês

10.1016/s0044-328x(75)80138-3

0044-328X

Ingrid Capesius, Wilhelm Barthlott,

Photosynthetic Processes and Mechanisms

Radioactive labelling with tritiated water and 32P-orthophosphate is used to demonstrate that the velamen radicum of the aerial roots of the orchids Angraecum, Cattleya, Epidendrum, Oncidium and Rodriguezia transports absorbed water quickly to the living tissue. In Vanilla planifolia the aerial root cannot absorb water. Here only the modified rhizodermis in contact with an underlying substrate takes up water. Scanning electron microscope studies show that the velamen of Vanilla is morphologically different from velamen found in the other genera. A relationship between structure and function can be demonstrated. The rather complex fine structures of the cell walls are studied in detail for the first time. In different genera the velamen can take over thoroughly different biological functions.