Pak. J. Bot., 36(4): 701-710, 2004. | Back to Contents | ||||
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Updated: 09-07-09 | ||||
POLLEN MORPHOLOGY AS AN AID TO THE IDENTIFICATION OF SCORZONERA (CICHORIEAE-COMPOSITAE) FROM PAKISTAN AKBAR ALI MEO AND MIR AJAB KHAN
Abstract: Pollen morphological characters of 5 species of Scorzonera have
been investigated from Pakistan by light microscopy. Pollen grains are
usually radially symmetrical, isopolar, prolate-spheroidal in equatorial
view, semi-angular to inter-semi-angular in polar view, trizonocolporate,
non-lacunate and echinate. Pollen characters such as size, shape, colpi
and exine thickness, and aperture type are found considerably important.
Scorzonera hondae can be distinguished due to its sub-prolate
shape whereas S. picridioides has oblate-spheroidal subprolate
P/E ratio (0.95). The pollen spine character is a diagnostic character
in this genus. S. hondae has the highest spine length (4.8 µm)
and S. laciniata can be distinguished due to lowest spine length
2.5 µm. There is a great range of variation in exine thickness
which has proved useful at specific level. On the basis of exine thickness
3 groups viz. Group 1: S. virgata, S. laciniata, Group
II: S. picridioides, Group III: S. ammophila, S. hondae
are recognized.
Department of Biological Sciences,
Quaid-i-Azam University Islamabad (Pakistan). |
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