Pak. J. Bot., 38(1): 29-41, 2006. | Back to Contents | ||||
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Updated: 09-07-09 | ||||
POLLEN MORPHOLOGY AS AN AID TO THE IDENTIFICATION OF CHRYSANTHEMUM SPECIES (COMPOSITAE-ANTHEMIDEAE) FROM PAKISTAN AKBAR ALI MEO AND MIR AJAB KHAN*
Abstract: Pollen morphology of 7 species of
Chrysanthemum has been examined from Pakistan by light and scanning
electron microscopy. The pollen grains in all the species are
trizonocolporate. Pollen shape in polar view is circular,
inter-semi-angular and semi-circular to angular. Pollen is spheroidal,
sub-spheroidal, oblate-spheroidal and prolate-spheroidal in equatorial
view. Taxa of Chrysanthemum species can be distinguished by
pollen size, exine thickness, spine length and number of spine rows
between colpi. Chrysanthemum indicum has characteristic spines
having a broad flattened base with grooves. C.stoliczkai has the small
spine length (3.3 m) while C. indicum can be characterized by
long spine length (5.9 m) and C. tibeticum can be distinguished
due to lowest number of spine rows between colpi (3-4). Chrysanthemum
stoliczkai and C. parthenium are determined by long exine
thickness (7.9 m) and (9.5 m) within the genus. This study demonstrates
the potential of pollen studies in distinguishing some taxonomic groups
in Anthemideae. There is great range of variation in exine thickness
which has proved useful at specific level. On the basis of exine
thickness, 4 groups viz., Group I: C. tibeticum, Group II: C.
indicum, C. segatum, Group III: C. leucanthemum, C. murifolium
and Group IV: C. stoliczkai, C. parthenium are recognized.
Department of Biology, Govt.
College Satellite Town, Rawalpindi. (Pakistan) |
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