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Summary
The present work is based on the Morpho-taxonomical studies of
some members of family Asclepidaceae found in Lucknow and its
adjoining areas. The family Asclepiadaceae is commonly known as
‘milkweed’ family because of containing milky juice (latex) in its stem.
This common name milkweed refers due to the white latex mentioned
earlier. The presence of simple opposite leaves with no teeth on their
edges is unique markers of the family. The name Asclepiadaceae came
from Asclepias genus which in tern is named for Asklepias, the God of
healing in Greek mythology.
Family Asclepiadaceae includes about 250 genera and over 2000
speceis. In India there are about 35 genera 234 species including 172
endemic species. Members of the family are mainly distributed in tropical
and subtropical areas but some species are found in temperate zones
especially in Africa and Southern South Africa, with a moderate
representation in Northern and South Eastern Asia. Plants are found in
Himalayan and Sub-Himalayan regions. They also grow in Nilgiri hills
and planes of Uttar Pradesh, Bihar, Madhya Pradesh, West Bengal and
Punjab. Most of the plants are ornamental and growing in the garden.
Calotropis sp. (Ait.) R. Br. Aiton, grows as a weed in Bihar, Uttar
Pradesh, while Cryptostegia sp. (R. Br.) commonly grow throughout
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India as a climber. However, Hemidesmus (L.) R. Br. Ait. grown in
Bihar and Periploca is found in outer Himalayas
Most members of Asclepiadaceae have milky juice, flowers with
five united petals, podlike fruits, and usually, tufted seed. Male and
female parts of each flower are united in a single structure known as
gynostegium and the pollen is characteristically massed in bundles, called
Pollinia. Pairs of which are linked by a yolk like tissue contributed by the
stigma of the pistil. Parts of the Pollinia stick to visiting insect pollinators,
which then carry them to other flowers to facilitate cross-pollination. The
silky hair seeds are drawn out of their pods by the wind and then carried
off. In some species the fertility is low, and many plants often produce
few fruits. Many milkweed butterflies, including monarch butterflies, rely
exclusively on Asclepiadaceae plants as a food source for their larva.
A number of species are grown horticulturally for their beauty or
notable adaptations. Common milkweed (Asclepias curassavica) of North
America has bright orange flowers. Hoya longifolia, which is commonly
called as wax plants because of its waxy white flowers, often grows
indoors as a pot plants. The ant plant (Dischidia rafflesiana) is uniquely
adopted with hollow inflated leaves. The leaves can store rainwater or, it
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punctured, form a suitable netting chamber for symbiotic ants, which
protect the plants from harmful insects.
Asclepias curassavica is common in the Antilles, and is known to
be the main food source for the (also toxic) butterflies of the genus
Danaus (the monarch and its relatives). Several members of the family
develop their seeds in dry pods. The seeds often have fluffy tufts of hairs
that allow them to be dispersed by the wind.
The members of the family have great economic importance. As in
medicine, it is used for laxative, expectorant, diuretic, emetic purposes,
and also for wart removal. Milkweed roots have been used medicinally in
the tropics for pain relief and for the treatment of scrofula (A microbacterial cervical lymphadenitis). Some of the species of Asclepias
curassavica is ornamentally grow as a garden weed. Other species of the
Asclepiadaceae family, such as the Pitcher plant, or Dischidia rafflesiana,
and Hoya carnosa, are also popular as outdoor garden plants and indoor
potted plants. Many species are hardy and produce colour full fragrant
blooms that draw butterflies, bees and birds into the garden.
Calatropis gigantea (Willd.) Dry. ex Wt. Ait. (Madar), have been
used medicinally for a long time. Dried roots of Hemidesmus indicus
have been used to treat syphilis, rheumatism, psoriasis and eczema.
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Gymnema sylvestre
(Retc.) R.Br. is used in traditional system of
medicine as a stomachic diuretic and a remedy to control diabetes (Najafi,
2011).
Floral characters have long been used by taxonomists for the
identification of the taxa, but it has been established that epidermal
characters are also very useful for identification of the taxa within the
family or between the members of different families. Cuticular studies of
the family Asclepiadaceae have received little attention so far.
However, there is a need for more extensive critical studies on the
structure of epidermal cuticles were felt in view of the fact that much of
our knowledge of the Indian plants of the family Asclepiadaceae is still
meager. That’s why the family was undertaken for the study of epidermal
structures in view of the fact that they are closely related moreover they
show varied habits, they could be herbs, shrubs, trees and climbers.
Systematic position of controversial genera within the family was also
studied using epidermal characters.
The thesis embodies thorough studies of epidermal structures of
family Asclepiadaceae. Micro-morphological studies have been carried
out to economically and medicinally important plants of this family.
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Summary
Present study was aimed to study of some members of the family
Asclepiadaceae. Since, knowledge of epidermal characters of the family
Asclepiadaceae is meager; hence keeping in view of these afore
mentioned features, the present investigation was carried out to gather
critical knowledge on epidermal characters using light microscopic
studies of cuticles in terms of various aspects of trichomes, stomata etc.
Various epidermal features have been investigated in the present research
work such as: Epidermal shape, size and structures, presence/absence of
stomata on foliar surface, frequency of stomata and stomatal index,
presence/absence of trichomes, shape, size and structure of trichomes,
presence of trichome base, shape and special features.
Twenty genera and sixty species of the family Asclepiadaceae are
commonly found in Luknow. The member of the family has a great
economical and medicinal value.
The plant materials for the present study were collected from
different localities of the Lucknow city. The Lucknow city is situated
between 26o52’N latitude and 80o56’E longitude and 120 meter above the
sea level in the central plain of the Indian subcontinent. It is the capital of
Uttar Pradesh and one of the largest and highly populated states of India.
The city is spread over an area of 79 km2 and has a population of more
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than 1.7 million. It has distinct tropical climate with a marked monsoonal
effect. Three distinct seasons are prominent that is summer (March to
June), rainy (July to October) and winter (November to February). The
temperature ranges from a minimum of 5oC in winter to a maximum of
47oC in summer. The mean average rain fall 1006.8 mm and relative
humidity is 60%.
Some species have been taken from the garden of the Botany
Department, Lucknow University. While some other has been procured
from different institution viz. National Botanical Research Institute,
Lcuknow, Central Institute of Medicinal and Aromatic Plant, Lucknow.
Both fresh and herbarium material have been used for the present study.
The places from where the materials were obtained for the present
investigation are marked in the map. Various species such as Asclepias
curassavica Linn., Calotropis gigentea (L.) R. Br. in Ait., Calotropis
procera (Ait.) R. Br., Cryptolepis buccanani R. Br., Cryptostegia
grandiflora (roxb.) R.Br., Dragea volubilis (linn.) Benth., Hemidesmus
indicus (L.) R. Br., Hoya longifolia Wall. ex Wight et Arn., Leptadenia
reticulata (Retz.) Wight and Arn., Stapelia sp., Tylophora indica (Burm.
f.) Merr., Perguleria Daemia (Forsk) chiov., Oxystelma esculentum R.
Br. have been critically studied for epidermal characteristic features.
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Members of the family Asclepiadaceae are also unique due to the
association of pollen grains that form a sac like definite structure called
Pollinia (Singular Pollinium). They are the product of only one anther,
but are transferred during pollination as a single unit. This is also seen in
orchids. The pollinarium of most Asclepiadaceae is composed of two or
more Pollinia, each of which contains all of the microspores of a single
anther locule embedded in a hard matrix and a translator apparatus, which
develops from a stigmatic recreation and mechanically attached with
pollinia to a pollinator. The plants of the family are unique among the
dicotyledons in having a pollination mechanism closely related to that
which makes the Orchidaceae unique among the monocotyledons. In the
present study it was observed that the family Asclepiadaceae is
characterized by thick cuticle, presence of cuticular striations, thick
orstraight walled epidermal cells, frequent occurrence of trichomes and
stomata. Paracytic, anisocytic and both types may also occur in some
species. Group of cells are found in some species and cavities like
structure domatia were also recorded in Perguleria pallida. Though some
features are common however some other characters are so distinct to
classify and distinguish the genera and even species.
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The size of stomata on lower surface varied from 16x10 to 30x40
m with largest size in Oxystelma esculentum and smallest in Asclepias
curassavica. Degenerated stomata was recorded in Calotropis gigentea
and on upper surface the size ranged from 19x14 to 32x34 m with the
largest size in Calotropis procera and smallest in Hoya longifolia.
Trichomes are generally absent except in few species viz. Asclepias
curassavica (on both surface), Calotropis sp. (on both surface),
Leptadenia reticulata (on lower surface), Cryptolepis buccanani on lower
surface), Oxystelma esculentum (on lower surface), Dragea volubilis (on
lower surface) and in Perguleria pallida (on lower surface). Epidermal
cells are hexagonal, irregular and polygonal shaped. The size of
epidermal cells ranges from 12x10 to 30x35 m. with largest size in
Stapelia sp. and the smallest in Asclepias curassavica. Trichomes of the
investigated plants are unicellular, uniseriate and septated with the size
ranges from about 10 to 120.
For the pollinial studies fresh flowers in the form of inflorescence
were collected from different areas of Lucknow city, viz. Asclepias
curassavica (L). and Tylophora Hook from Kukrail area, Calotropis
gigentea (L.) Ait. Hort. and Calotropis procera (L.) Ait R. Br. collected
from Indira Nagar and Lucknow University, Cryptolepis Roem. and
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Schult. from Memora, Gymnema sylvestre (Retz.) R. Br. and Hemidesmus
indicus from Anaura, Stapelia sp. (L.) were taken from Garden of Botany
Department, Lucknow University, Lucknow.
The pollinium character is a unique
feature of family
Asclepiadaceae which size ranged from 79x43 to 961x373 m with the
largest pollinium in Calotropis gigentea and the smallest one in Asclepias
curasavica. The total size of caudicle or translator ranged from 61x32 to
129x39 m with largest in Hoya longifolia and smallest in Asclepias
curassavica, however, absent in Cryptolepis buccanani and Hemidesmus
indicus. The corpusculum size ranged from 26x17 to 282x153 m with
largest in Calotropis gigentea and smallest in Asclepias curassavica
which were absent in Cryptolepis buchanani and Hemidesmus indicus.
Usually pollinial sac was oval in shape except in Gymnema sylvestris and
Asclepias curasavica having intermediate shape and Tylophora indica
(Globular shape). These pollinial sacs attach to translator in apical, basal
or erect orientation.
These above mentioned investigations regarding epidermal
characters
as
well
as
pollinial
features
revealed
categorization of various species of family Asclepiadaceae.
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taxonomical