I= A PRELIMINARY STUDY OF THE POLLEN FLORA OF KARACHI
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Title of Thesis
A PRELIMINARY STUDY OF THE POLLEN FLORA OF KARACHI

Author(s)
Anjum Perveen
Institute/University/Department Details
Department of Botany/ University of Karachi
Session
1993
Subject
Botany
Number of Pages
385
Keywords (Extracted from title, table of contents and abstract of thesis)
pollen flora, angiosperms, dicots, monocots, acanthaceae, boraginaceae, convolvulaceae, polygonaceae, liliaceae, typhaceae, zygophyllaceae, rhamnaceae, polygalaceae, chenopodiaceae

Abstract
Pollen morphology of 351 species from Karachi, belonging to 67 families of Angiosperms, distributed in 58 dicots and 9 monocots have been investigated by scanning electron (S.E.M.) and Light microscope (L.M.). Considerable diversity in qualitative and quantitative characters, more especially in symmetry, polarity, shape, size, apertural types and cxine ornamentation have been observed. Pollen grains are generally isopolar-apolar, rarely subisopolar and heteropolar, commonly prolate-spheroidal to oblate-spheroidal or sub-prolate to prolate rarely spheroidal. Both types of apertures viz., simple and compound are fairly common. Grains are mostly colporate, colpate and porate rarely non-aperturate ones are also observed. The number and position of apertures also varies in different taxa. In some families namely Lythraceae, Acanthaceae and Boraginaceae more distinct heterocolpate grains are also found. Besides this, some miscellaneous type of apertures have also been observed in Neuradaceae (Neurada procumbens L.), Sapindaceae (Cardiospermum helicacabum L.) and Menyanthaceae (Nymphoides cristata (Roxb.) O.Ktze), Similarly exine sculpturing is also extremely varied, ranging from almost psilate, sub-psilate, reticulate, rugulate, fossulate, foveolate, striate, scabrate, echinate to tubuliferous spinulose. Some families viz., Acanthaceae, Boraginaceae, Convolvulaceae, Polygonaceae, Liliaceae, Typhaceae and Zygophyllaceae are eurypalynous and have quite distinct pollen types. In contrast to this, some families are fairly uniform in their pollen characters, as in Rhamnaceae, Polygalaceae, and Chenopodiaceae etc.

With few problematic exceptions, pollen data supports the general classification. The relatively most primitive pollen type i.e. monosulcate (l-colpate), heteropolar, bilaterally, symmetric pollen are restricted to the most primitive subclass of dicots i.e., Magnoliidae and to the monocots. In contrast to this the highly advanced subclass Asteridae exhibit greatest arry of specialized pollen types, more especially the family Compositae.

Pollen morphology of various orders in relation to the taxonomy is separately discussed.

Pollen vectors in relation to their respective pollination types are also discussed. In the present investigations insects are the major pollen vector, 65.24 % taxa are pollinated by insects, 33.04 % taxa utilizing wind as the dispersal agent and 1.71 % taxa are pollinated by birds and other agencies (Hydrophily)

Download Full Thesis
6010.14 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
60.25 KB
2 1 Pollen Morphology 5
5975.63 KB
  1.1 Introduction 6
  1.2 Introduction to study area 9
  1.3 Flora of Karachi 13
  1.4 Materials and Methods 14
  1.5 Key to the families 16
  1.6 Observation and results 27
  1.7 Discussion 278
3 2 Pollen characters and pollination types 311
639.89 KB
  2.1 Introduction 312
  2.2 Materials and methods 313
  2.3 Observation and results 314
  2.4 Discussion 345
  2.5 Appendix-1 348
  2.6 Acknowledgements 353
  2.7 References 354
  2.8 Index 373