INTRODUCTION
Verbascum includes 300 species worldwide (Huber-Morath, 1978) and 46
species (including hybrids) (Ghahreman and Attar, 1999) and is the largest genus
in scprophulariaceae, subfamily Verbascoideae, tribe Verbaceae (Valdes, 1987).
Hybrides are frequent in Verbascum. It is a southwestern Asian genus
centered in Turkey, Iran and Pakistan (Zohary, 1973). It is the endemic of Turkey.
Morphology and anatomy of fruits and seeds have shown similarities among the species of Verbascum in southern Spain (Juan et al., 1997). Foliar idioblasts have been reported in the anatomy of leaves in some of the species and there is a report about Verbascum’s affinity with Scrophularia (Lersten and Curtis, 1997). Molecular data shows relationship for Scrophularia and Verbascum according to ndhf, rps2, rbcl genes (Olmstead et al., 2001). Pollen morphology of some species of the genus has been examined by many researchers (Dane and Yilmaz, 2002; Moor and Webb, 1978. However there are almost no reports on the pollen morphology of the species found in Urmia.
MATERIALS AND METHODS
Materials used for this study was collected from wild populations around Urmia. Mature pollen grains of seven species were obtained from dried herbarium specimens. Pollen grains were acetolized using the technique presented by Erdtman (1960). Morphological observations were made in a Philips LX30 Autoscan SEM and LM BX40 Olympus.
RESULTS
The structure of pollen wall was found to be rather uniform in all investigated taxa. The tectum surface is reticulate-microreticulate and all the pollen grains are tricolporate and have the polar diam that range from 25.08 to 41.38 μm and the equatorial diam that range from 15.04 to 35.11 μm.
The polar equatorial diam ratios (P/E) of pollen grains show that shapes are prolate, prolate sphroidal to perprolate.
The colpi are distinct, the colpus membranes are covered sparsely. The shape of the colpi are fusiform. The pollen grains are isopolar.
Apocolpium is present on all pollen grains where colpi are three at the poles.
Verbascum szovitsianum Boiss.: Pollen grains prolate to prolate
spheroidal, polar axis 25.08-36.36 μm and the equatorial diam 16.30-30.09
μm (P/E ratio 1.04-1.93) outline at the polar view mostly circular to subtriangular
with convex sides, outline at the equatorial view prolate to elliptic. Tectum
reticulate (Fig. 1A-C).
Verbascum agrimonifolium (C. Koch)Hub-Mor.: Pollen grains prolate
to prolate spheroidal, polar axis 25.08- 37.62 μm and the equatorial diam
15.048-30.96 μm (P/E ratio 1.08-2).
Outline at the polar view mostly circular to subtriangular, outline at the
Equatorial view mostly prolate. Tectum microreticulate, reticulate supragemmate
(Fig. 1D and E).
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| Fig. 1: |
A-C: Verbascum szovitsianum; (A) equtorial view scale bar 10 mm; (B and C) polar view (B) scale bar 2 μm (C) scale bar 10 μm, D-E: V.mucronatum; (F) details of ornamentation scale bar 2 μm (I)polar View scale 10 μm, J-K: V.mucronatum (J) polar view scale bar: 5 μm; (K) details of ornamentation scale bar 2 μm; (L) V. oriphilum equatorial view scale bar 5 μm |
Verbascum mucronatum Lam.: Pollen grains prolate to prolate spheroidal,
polar axis 25.08-40.12 μm, equatorial diameter 15.48-28.84 μm (P/E
ratio :1.1-2)
Outline at the polar view mostly circular, outline at the equatorial view mostly
oblate circular. Tectum reticulate (Fig. 1F and G).
Verbascum sinuatum L.: Pollen grains prolate to prolate spheroidal,
polar axis 25.08-37.62 μm, equatorial axis 15.04-25.08 μm (P/E ratio
1.25-1.85).
Outline at the polar view mostly circular, outline at the equatorial view prolate.
Tectum reticulate. The size of pore 4.43-5.17 μm in length and 2.39-3.37
μm in width, apertures lolongate. Colpi clear without granules (Fig.
1H and I).
Verbascum macrocarpum Boiss.: Pollen grains prolate to prolate
spheroidal to perprolate, polar axis 25.08-41.38 μm. The equatorial diam
15.04-35.11 μm (P/E ratio: 1.12-2.07). Outline at the polar view mostly
subtriangular. Outline at the equatorial view prolate, elliptic. The colpus
surface is grandular sparsely. Tectum reticulate with extended muries (Fig.
1J and K).
Verbascum oreophilum C. Koch var. oreophilum (BORDZ) Hub-Mor.:
Pollen grains prolate to prolate spheroidal, polar axis 25.08-35.11 μm
and the equatorial diam 15.048-28.84 μm (P/E ratio:1.09-1.83) outline at
the polar view circular, outline at the equatorial view oblique. Tectum reticulate
(Fig. 1L).
Verbascum cheirantifoluim Boiss.: Pollen grains prolate to prolate
spheroidal, polar axis 25.08-35.11 μm and equatorial axis 15.048-28.84
μm (P/E ratio:1.09-1.83), outline at the polar view circular to subtriangle,
outline at the equatorial view oblique. Tectum reticulate (Fig.
1M).
DISCUSSION
The results from present observation show that all Verbascum species have the same basic type of pollen morphology (reticulate). All the taxa examined are essentially similar in pollen morphology and have the same basic shape-their pollen grains are spheroidal prolate or prolate to perprolate. Tricolporate with three long tapering furrows and lolongate pori. These data support the results given by other workers on the other species of Verbascum (Dane and Yilmaz, 2002).
ACKNOWLEDGMENTS
We are grateful to the experts of the herbarium of Natural science specially Mrs. Larti who kindly helped us identifying the plant species and Miss Heidari finding the location of the species. We are grateful to the SEM expert Abdolhamid Rezaii at Tarbiat Modarres University for scientific experience of using the microscope.
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