ABSTRACT
Among alkaloid-enriched cells, the fluorescence from the root of Ruta graveolens L is very bright (Roshchina, 2005b) which is demonstrated in Colour Fig* 19 Appendix 2. The root tip shows the yellow-orange fluorescing excretions with high maximum 595-600 nm, while other smaller maximum 465470 nm is in blue. Unlike secreting tip meristem, root hairs demonstrate small fluorescent components with maximum 590600 nm, and higher peak at 465-470 nm. Single secretory cells, called idioblasts, are also seen in the root of the species and fluoresce as crystals, mainly, in the yellow-orange spectral region with the highest maximum 595600 and smaller - at 465470 nm. Non-secretory cells emit in blue-green with only one maximum 475 nm. The fluorescence of secreting root cells depends on the chemical composition of their secretions and may be changed among various rue cultures. For instance, cells of pRi-transformed roots of Ruta graveolens L cultivated in vitro contain acridone alkaloids, whose location is seen due to their orange fluorescence (Kuzovkina et al., 1999). In non-differentiated cells of callus and roots, acridone alkaloids are accumulated in idioblasts or excreted on the cellular surface and into the nutritional medium, and fluoresce as seen in Fig. 2.33. The fluorescence spectra are similar with those of the root secretory cells: high maximum 595-600 nm in the orange spectral region and smaller (if any) maximum in blue at 460465 nm. A similar composition of the fluorescent secretions is proposed. Non-secretory cells fluoresce mainly in blue with peak 460465 nm, and smaller maximum is seen in orange 595-600 nm.
