Keywords (Extracted from title, table of contents and
abstract of thesis)
Polygonaceae, Distinctive, Major,
Anatomical, Features, Taxonomic, Evolutionary, Complex, Stomata,
Genera, Pakistan, Rumex, Studies, Complex, Original |
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Abstract
The detailed
taxonomic study of the Complex genus Polygonum L. (segregated into
six genera and discussed separately in the present account) and
Rumex L.of Polygonaceae has been carried during 2006-2009. Material
for morphological, anatomical and palynological studies was obtained
from the herbarium specimens and freshly collected material while
for Amplified Fragment Length Polymorphism (AFLP) only fresh samples
were used. Forty eight species belonging to seven genera, Aconogonon
(Meisn.) Reichenb., Bistorta Adans., Fagopyrum Mill., Fallopia Adans.,
Persicaria Mill., Polygonum L. and Rumex L. were morphologically
reviewed in detail, original observations being supplemented by and
compared with previously published information. 6 new taxa were
described first time in this account and proposed to be the new
varieties. These included three varieties of Polygonum aviculare L.,
two varieties of Polygonum paronychioides C. A. Mey. ex Hohen and
one variety of Polygonum polycnemoides Jaubert & Spach.
Leaf epidermal studies have been carried out on forty seven species
of the family and observations are made through traditional light
microscopy.To my knowledge no such work is yet known which has dealt
with comprehensive qualitative and quantitative micromorphological
foliar investigations in the taxa of
Polygonaceae from Pakistan.The study revealed some distinctive
anatomical features on adaxial and abaxial leaf surfaces such as
epidermal cells outline, single or mixed type of stomata on the
single leaf surface and presence or absence of trichomes.The shape
of epidermal cells is found to be variable; six different stomatal
patterns have been examined, including cyclocytic, pericytic and
staurocytic stomata not reported earlier for the family. Variation
among glandular and non glandular trichomes is also examined.
Glandular trichomes are of peltate, capitate and spheroidal type
while five types of non glandular trichomes are also examined.
Crystalliferous cells have been reported first time in Rumex
nepalensis Spreng.Although analyzed epidermal characters have
systematic value but they are likely to be stable at specific and
generic level and are not much helpful in generic delimitation.
Pollen morphological characters have been investigated by light
microscope (LM) and scanning electron microscope (SEM). Both
qualitative and quantitative characters including aperture number,
pollen shape, size in polar and equatorial view, colpi length, exine
and intine thickness and exine sculpturing in both LM and SEM have
been observed.The characters employed, have been proved to be useful
in classification of the complex genus Polygonum L. into different
genera. On the basis of aperture number and exine sculpturing
pattern in SEM, 14 main pollen types and 6 subtypes namely,
Aconogonon type, Bistorta type, Fagopyrum type, Dumetorum type,
Convolvulus type, Persicaria type (further subdivided into three
subtypes), Capitata type (subdivided into three subtypes), Plebijum
type, Patulum type, Cognatum type, Avicularia type, Chalepensis
type, Acetosa and Dentatus type have been identified.These different
pollen types are arranged in three parallel directions to establish
evolutionary trends in pollen types of seven genera of the family
Polygonaceae.
To examine inter and intraspecific relationship among 28 accessions
of 13 species belonging to four genera, AFLP (Amplified Fragment
Length Polymorphism) marker system was first time used. Single
primer pair was used to amplify AFLPs and fragments were separated
in 6% denaturing acrylamide gels. A total of 131 fragments were
analyzed. According to present results, the AFLP knowledge was found
to be sufficiently susceptible to identify small level of variations
and can differentiate highly interrelated genotypes.
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