SPATIAL CONGRUENCE BETWEEN EXINE PATTERN, MICROTUBULES AND ENDOMEMBRANES IN VIGNA POLLEN

The role of microtubules and endomembranes in pollen wall pattern form ation in Vigna vexillata L. was examined using fluorescence laser scan ning confocal microscopy. Indirect immunofluorescence using anti-beta- tubulin antibodies revealed that the arrangement of the cortical The r ole of microtubular cytoskeleton in microspores resembled the reciproc al of the reticulate ektexine ornamentations of mature V. vexillata po llen. Patches of microtubules in cortical cytoplasm corresponded in lo cation with the lumina of the exine reticulum and with apertural sites . Microtubules were absent from cytoplasm under muri (ridges) of the e xine reticulum. Labeling of microspores during the mid-tetrad stage wi th the endomembrane-specific fluorochrome DiOC(6) produced a pattern s imilar to that of the microtubules; i.e., DiOC(6) staining was localiz ed in cytoplasm underlying lumina and absent from cortical cytoplasm u nderlying sites of muri. This report represents the first observation of congruence of the pattern of occurrence of any subcellular organell es with exine pattern and, in particular, the congruence of both micro tubules and endomembranes in cortical cytoplasm with the lumina of the reticulate exine.