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SEMINAR ON
M.Sc II Sem
♦ The branch of science concerned with the study of fossil and living palynomorphs
Study of pollen, spores, and other microscopic plant bodies collectively called PALYNOMORPHS. e.g. algal cysts (dinoflagellates), algae, fungal spores, etc.
Palynology (Gr, palynos , dust)
Study of pollen, spores, and other microscopic plant bodies collectively called PALYNOMORPHS. e.g. algal cysts (dinoflagellates), algae, fungal spores, etc.
Plants produce either pollen or spores
Acritarchs
Chitinozoans
Scolecodonts
Microscopic Algae and Algal Parts
Cryptospores
Embryophyte Spores
Pollen
Dinoflagellates
Chitinous Fungal Spores and Other Fungal Bodies
Microforaminiferal Inner Tests
Megaspores
Palynodebris
Varia
POLLEN & SPORES ARE EVERYWHERE 1 0 00 B EFound in the air over the middle of the oceans
1 0 00 B EFound in the air all over the world including the air over the North and South Poles 1 0 00 B EFound in rivers, lakes, seas, and at the bottom of the oceans 1 0 00 B EFound inside buildings, in cars, on and inside animals, on and inside people, in soils, and rocks up to 2.2 billion years old. 1 0 00 B E There are about ½
million plants that produce either pollen or spores, each species produces a unique type of pollen or spore 1 0 00 B E Some plants are
wind-pollinated & disperse millions of pollen grains or spores, most of which (~90%) fall very close to the plant; a few might travel great distances 1 0 00 B EDuring an average spring or
summer day in most areas each cubic meter of air contains about 1,000-20,000 pollen & spores 1 0 00 B EThe average adult inhales
pollen based studies are now relevant in various areas of Botany as well as in several other disciplines like Agriculture,
What is Forensic Botany?
Introduction
In general the spores of bacteria, fungi, algae and protists are rarely preserved but those of terrestrial plants are very common fossils. Terrestrial plants produce extremely resistent spores and pollen which are easily transported by wind and water. Most fossil spore and pollen grains are studied in a dispersed state and this is the fundamental basis upon which Hyde and Williams (1944) initially proposed the term Palynology. The initial meaning has now been expanded to include all acid-resistant organic microfossils. Spores are produced by the so-called "lower plants" or cryptogams, and within this group the pteridophytic vascular plants and bryophytes (mosses, liverworts and hornworts) are the most commonly studied. Pollen of seed plants, both angioperms and gymnosperms increasingly dominate palynological assemblages of Mesozoic and younger nonmarine deposits.
History of Study Observations of pollen by Grew and Malpighi are recorded from shortly after the invention of the microscope in the mid 17th Century. One of the very earliest practical applications of preserved pollen in the reconstruction of changing environments was by the Swedish palynologist Von Post in
Erdtman’s, (1952) book “Pollen morphology and plant
taxonomy in Angiosperms” laid a solid foundation to this branch of study and demonstrated the importance of pollen morphology in plant taxonomy Range The earliest terrestrial plants are recorded from the late Siluria these were homosporous (all spores produced are of the sam the end of the Devonian heterospory had appeared, this still in dispersal by spores only but both microspores (held in a
genetic systems plants may utilise hybridisation and self fertili early gymnosperms produce prepollen, differentiated from tru germination from the proximal rather than the distal side. Rec gymnosperms may produce very distinctive saccate pollen, i.e with one, two or rarely three air sacs attached to a central bod or monosulcate pollen as in the cycads and ginkgos. The ang produce pollen with the greatest morphological variation, but t with either a tricolpate or monosulcate form.(See Biology belo
Applications
While botanical information from them may be limited, fossil s pollen have proved exceptionally useful as biostratigraphic ind are particularly valuable in freshwater environments, in evapo deposits and situations where marine and freshwater facies in
Biology
Spores, in the broadest sense, are produced in the life cycles "lower plants" or cryptograms, comprising algae, fungi, bacter extensive array of seedless metaphytes. Two basic forms of s recognised based on the original relationship of the spore tetr the sporangium. In tetrahedral tetrads each of the four spores contact with all three of its neighbours on its proximal face, th spore a distinctive trilete or Y-shaped mark. In the tetragonal t of the four spores was in contact with only two of its neighbou proximal face, this gives each spore a distinctive rectilinear sc typically bean-shaped outline. An important point to remembe studying preserved spores is that they are generally compres distally, that is along the polar axis, so care is required to diffe
betwen folds and trilete or monolete marks. Further subdivisio is based on wall sructure and ornamentation.
Pollen is produced by seed plants, both angiosperms and gym Pollen has a cellulose wall around the protoplasm called the i this is the sporopollenin layer which is inert, very tough and re bacterial attack, this layer is called the exine. The pollen of se gymnosperm genera is saccate; that is, grains bear one, two three air sacs attached to a central body or corpus. Angiosper extremely diverse and covers a multitude of combinations of f Individual pollen grains may be inaperturate, or provided with pores (monoporate, diporate, triporate, etc.), slit-like apertures (monosuclate, tricolpate, etc.), or a combination of pores and (tricolporate, syncolporate etc.).
Lifecycle
Vascular plants (those with special conducting tissues called x a similar alternation of generations as their algal forebears. Al occurs between spore-forming sporophyte generations (repro asexually) and a gamete-producing gametophyte generation ( sexually with male and female gametes). In vascular plants, u the sporophyte generation predominates, this is charcterised production at certain times of year of a spore-containing caps sporangia. The first land plants to appear were homosporous, they produce spores of one kind only also called isospores. M are homosporous, the diploid (2n) sporophyte plant produces haploid (1n) spores in sporangia (sac-like packages) underne leaves. These are ejected onto the ground, which must be da the germination of the gametophyte (still haploid) stage. The g then produces either eggs or sperm, the spermatozoid swims
coincidental release, the advantage is that the megaspore con food reserve to give the new plant a head start, and only mois conditions are required for fertilisation to take place. In the fos megaspores are considered those spores over 200 microns a which is a rather arbitrary division but is widely accepted.
In the seed gymnosperms (for instance pines) the megaspore is held within the plant and the microspore has to reach it by being carried by the wind, hence the very small size of gymnosperm "spores", which are called pollen. The pollen is trapped by a droplet of liquid at the entrance to a chamber which contains the megaspore. When pollen is trapped sperm travel down a special canal to fertilise the megaspore which remains within the plant and is fed by it. This produces a seed which contains its own food
reserves ready to be released when conditions are right. The advantage over heterospory and homospory is that no water is required in the process but a vector (the wind) is needed and the process is very slow, for instance pines take two years to produce seeds after fertilisation.
Types of Pollination
Pollination is the transfer of pollen from the male part of a plant to the female part of a seed plant.
Two techniques for washing the acid out of the samples can b The decanting method involves allowing the acid and sample settle and then carefully decanting off the acid, topping up wit water and repeating until the liquid is neutral, but this is a time consuming method. The second method is to wash the acid a mix through an acid resistant sieve gauze of a mesh size suita retain the palynomorphs. The mesh sizes often used are ten a micron, ten micron gauzes being fine enough to catch all but t smallest spores and acritarchs, so if it is known these may be five micron mesh size may be used. Staining of samples (with Safranin-0, a red colour, for exampl used depending on the natural colour remaining in the palyno Coals and "coal-like" samples are often so devoid of mineral m the initial acid treatments can be omitted and oxidation only is This needs careful handling, however, as the oxidising reactio extremely vigorous. Kerogen slides are often required and req special preparation technique, without any oxidation or sieving the total organic matter preserved in the sample. Once all acid and separation processes are complete the sample may be m strewing onto cover slips and allowing to dry. The inverted cov then glued onto a slide using Norland Optical Adhesive or Pet similar proprietary glue of sufficient refractive index.
1- Crushing the sample in a mortar to the powder size 2- Transferring the crushed powder into a Nalgene plastic beaker that is resistant to high temperature
3- Conc. HCl treatment 4- Washing and neutralization 5- Conc. HF treatment 6- Washing and neutralization
7- Conc. HCl treatment 8- Washing and neutralization 9- Sieving the sample in a 125 μm brass sieve and collecting the residue in a 5-15 μm nylon sieve 10- Making permanent Kerogen slides 11- Oxidation if necessary 12- Making permanent oxidized slides
Palynology slides are examined using transmitted light micros commonly with times forty dry and times one hundred oil imm objective lenses. Accurate co-ordinates of individual specimen slide may be required and are often given using either the gra scale on the traverseable slide table of a particular microscop preferably by giving England Finder co-ordinates. An England a specially made slide which is divided into a grid of segments given an alpha-numeric reference. When a specimen is locate slide the slide is carefully removed from the microscope and r by the Englnd Finder and the co-ordinates marked down, as l orientation of the slide is also noted it is then possible to re-lo specimen using the England Finder on any microscope.
