| Abstrakt: |
SummaryTo find more morphological characteristics useful for discussion on aralian or non-aralian Panaxaffinity, pollen morphological diversity was comparatively analysed in P. ginseng, Aralia elataand Oplopanax elatuscollected during their pollination periods. In the anthers of both the buds and open flowers, the pollen average diameter varied between some species-specific maximum and minimal measurement. However, the larger pollen grains were typically found in the buds whereas the smaller pollen prevailed in the open flowers, testifying to the pollen size diminution during anther maturation. Based on this finding, the subsequent examination of pollen according to size decrease was put into operation as a method of pollen modification for the study. The structural mechanisms of pollen metamorphosis were identified as not being species specific but rather universal. These mechanisms are suggested to be the shrinkage of the pollen vegetative cytoplasm, the intine enlargement, the deepening of three colporate apertures provided by exine sunken into enlarged intine areas, the aperture accretion as well as the transformation of the exine from thick/sculptured into thin/less sculptured. During ?size-reducing metamorphosis?, the pollen grains changed dramatically, going through a species-specific set of intermediate morphs to the final species-specific morphotype. In P. ginsengthis morphotype is round (diameter is about 16 ?m), in A. elatait is round with a single projection (diameter is about 15 ?m) and in O. elatusit is ovoid with a single projection (average diameter is about 18 ?m). In addition, every species is peculiar in having the unique vegetative cytoplasm inclusions and individual construction of the largest pollen exine. From a phylogenetic perspective, these findings presumably add support to the option of equal remoteness of P. ginsengfrom A. elataand O. elatus. The characteristics found seem to be suitable for examination of Panaxaffinity, by the subsequent study of more Araliaceae representatives. [ABSTRACT FROM AUTHOR] |
