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METHODS
For living,fixed,herbarium and difficult materials
different methods were used, described as under:
(i) living and fixed material: From living as well as fixed
leaves and other organs epidermal peels were taken by
direct peel method. The epidermal peels were stained with
Delafield’s hematoxylin,washed in tap water, then distill
water and mounted in glycerine jelly following the method
of Johansen (1940).
(ii) Herbarium material: The herbarium materials after boiling
in distil water were transferred to 70$ ethanol. For quick
results, in case of difficult materials, maceration was done
by boiling in 0.25$ HNQ3 subsequently transferred to 70$
ethanol. The epidermal peels were very easily taken from
both the surfaces by this method.
(iii) Young and delicate material: The young and delicate materia
of which the epidermal peels could not be easily taken, were
soaked in 5$ aqueous NaOH solution, rinsed in running water
for about an hour, then washed in distil water, clearing was
completed in a 50$ NaOCl solution. The organs quickly became
transparent by this method, so that the upper and the lower
epidermis of an organ could be easily studied in a whole
mount of a single preparation.
(iv) Difficult material (Replicating method): The difficult
material of which the peels could be easily taken and also
24
with a view to compare my results based on epidermal
peelings, a new and easy technique was evolved to take
epidermal imprints using mucilage from 15 species, latex17 species, gum 3-species, egg albumin of three animals
and fevifix following the method of Inamdar, Patel and
Bhatt (1970).
(v) Eor plasmodesmata: Epidermal peels from fresh leaves of
Hygrophila auriculata. Pedalium murex and Sasamum indlcum
were stained following the method of Johansen (1940) for
demonstrating the plasmodesmata in the epidermis and
satisfactory results were obtained.
(vi) Statistical data: Mean values of 15 readings showing size
of epidermal cells, stomata, percentage of different types
of stomata, stomatal frequency and index were compiled with
the help of 'Eacit' computor machine and charted in tables.
(vii) Stomatal index: Salisbury’s (1927, 1932) following method
was used for stomatal index:
I =
s x 100 in which "S” is the number of stomata
|p-£—jj?
and "E” is the number of epidermal cells in a given surface.
(viii) Drawings and microphotographs:- Camera lucida drawings are
made from epidermal peels. Mostly drawings of the lower
epidermis are given in case of bifacial organs but where-ever
there is a difference in the structure of the abaxial and
adaxial surface, the drawings of the adaxial epidermis are
also given.
also given. The developmental stages only are stippled
showing nuclei in order to distinguish them from the
remainder of the epidermis. The stomatal cells stippled
without nuclei are arrested developmental stages. Microphotogr
are taken with the help of Carl Zeiss research trinocular
using incandescent light, yellow filter and ORWO DK5
document film.
TERMINOLOGY
(i) Stoma; The term 'stoma* is derived from a greek word meaning
pore. But here as has been accepted by the leading anatomists,
the term stoma is used to indicate the pore enclosed by two
guard cells.
(ii) Stomatal apparatus or stomatal complex: The stoma enclosed
by neighbouring surrounding cells which helps in its
functioning is called a "Stomatal apparatus" or "Stomatal
complex",
(iii) Neighbouring surrounding cells:
(a) Epidermal cells: The
neighbouring surrounding cells enclosing a stoma and not
differing in structure, size, shape and form the remaining
epidermal cells are called ordinary epidermal cells, (b)
Subsidiary cells: The neighbouring surrounding cells which
are different from the ordinary epidermal cells mostly by
their special size, shape, dimensions and differential
staining properties are called subsidiary cells. They may be
perigenous or mesogenous: (i) Perigene subsidiary cells: The
subsidiary cells cut off from the epidermal cells surrounding
26
a stoma, (ii) Mesogene subsidiary cells; The subsidiary cell
are cut off from the meristemoid which gives rise, to the
guard cells.
(iv) Distribution of stomata: Mostly stomata occur in large
numbers in the lamina of vascular plants but they are also
recorded on the other vegetative and floral organs such as
stem, petiole, stipule, bract, bractiole, peduncle, pedicel,
calyx, corolla, stamen (filament and anther epidermis),
carpel (ovary wall, style, stigma) and pericarp. Stomata
are absent in roots. Following four types of stomatal
distribution are recognised in bifacial organs:
(a) Astomatic: The stomata are absent in the upper and lower
....
t
surface of a bifacial foliar organ. According to Fahn (1967)
submerged leaves of aquatics are astomatic which requires
confirmation (see. Inamdar et al 1971).
(b) Hypostomatic: The stomata are present only on the lower
surface of an organ.
(c) Epistomatic: The stomata are present only on the upper
surface of an organ. Floating leaves of aquatic are epistomat
(d) Amphistomatic: The stomata are present on both the abaxial
as well as adaxial surface of an organ.
(v) Position of stomata: The position of stomata in relation
to the epidermal level differs from species to species and
it may be "Phaneropore" or "Cryptopore".
2v
(a) Phaneropore: The stomata which lie in the same level
as the epidermis are called phaneropore.
(b) Cryptopore: The stomata, when are deeply sunken below
the level of the epidermis as is the case in xerophytes are
called cryptopore,
(vi) Structure of stomata:
(a) Acyclic: The stomatal guard cells are surrounded by
neighbouring cells not different from remaining epidermal
cells.
(b) Hemicyclic: The stomatal guard cells are surrounded by a
half ring of subsidiary cells.
(c) Monocyclic: The stomatal guard cells are surrounded by
one complete ring of subsidiary cells.
(d) Amphicyclic: The stomatal guard cells are surrounded by
two or more complete rings of subsidiary cells. The
amphicyclic stomata are termed "diacytic" when surrounded
by 2, "triacyclic" by 3, "tetracyclic" by 4 or "poLycyclic"
by more complete rings of subsidiary cells.