NMR imaging as a tool for noninvasive taxonomy:: comparison of female cones of two Podocarpaceae

Nuclear magnetic resonance (NMR) imaging was investigated as a tool for the detailed morphological comparison of two species of Podocarpaceae of taxonomic interest; these were difficult to investigate by conventional methods. Two- and three-dimensional NMR images of female cones of Afrocarpus falcatus and Prumnopitys ferruginea were acquired using a range of protocols. Conventional sectioning and microscopic techniques and low-temperature scanning electron microscopy were used where possible, to corroborate the assignments of the NMR images. A three-dimensional network of resin canals in Prumnopitys ferruginea was revealed and the presence of resin confirmed by chemical shift imaging. Similar canals in cones of Afrocarpus falcatus did not contain resin but the presence of spoke-like vascular traces passing through the sclerotesta was demonstrated. marked differences in the structure of the sarcotesta of the two species were readily discernible. NMR imaging allowed noninvasive retrieval of both internal morphological and histochemical information from single specimens in their natural state in a much shorter time than conventional methods would allow and provides useful data for taxonomic purposes in the Podocarpaceae.