The Development of Palynology

Hyde and Williams coined the word 'palynology' in 1945 as a substitute for the science of pollen grains and spores. The term 'pollen' in Greek means 'flour'. Palynology is therefore derived from the Greek verb 'palynein' meaning - to strew; to spread; to disseminate; to distribute in recognition of the fact that many pollen grains and spores are easily carried by the wind. However the systematic study of pollen and spores was initiated much earlier.

The function of pollen grains and their role in pollination and fertilization was known to ancient Assysrians. There is a large number of evidence in the form of illustrations and lithographs available to show that artificial pollination of Date Palms (Phoenix dactylifera) was a regular practice known to Assyrians and Babylonians in 700 B.C. Figure 2.1 shows an eagle-headed human holding in one hand a bucket full of pollen and the other hand with male inflorescence dusting pollen on female flowers of date palm. This is also known from iconography dating as far back as 4000 - 3000 B.C. At the present time also artificial pollination of Date Palms (Fig. 2.2) is done as depicted in Fig. 2.3 in which a Japanese botanist is seen in action.

The study of pollen grains began after the discovery of the microscope by Robert Hooke in 1665. He described this microscope in 'MICROGRAPHIA' published in London in 1665 some 350 years ago. Each notable improvement in the construction of the microscope has always been reflected with a corresponding relevance to the study of pollen morphology. Almost simultaneously Malpighi and Grew observed, and described pollen grains by using Robert Hooke's microscope.

Thus, Malpighi and Grew may be recognized as the co-founders of pollen morphology. Wodehouse (1935) in his book on 'POLLEN GRAINS, their structure, identifications and significance in science and medicine' has included an excellent chapter on 'Historical Account of Palynology' which includes an exhaustive account of development of palynology from its

Assyrian Eagle Headed Tree
Fig. 2.1 Artificial pollination of Date Palm (Phoenix dactilĂ­fera) by an ancient Assyrian dated 4000-3000 B.C.: eagle headed human holding bucket full of pollen and dusting pollen on female flowers with a male inflorescence.

inception up to 1935. He discussed major developments in palynological knowledge in different centuries from the 13th to the 20th . Hence, we do not intend to repeat the same here. However, the main purpose of this account was to derive inspiration from the early founders and developers of the science of palynology and to understand and appreciate the efforts made by them in contributing to this science, many times under adverse working conditions. However, a brief life sketch and important palynological contributions of a few outstanding palynologists along with their significant achievements will be incorporated. Palynology is the scientific study of pollen and spores. It includes not only present day but also fossil examples. The study of fossilized plant material is part of the botanical discipline known as palaeobotany.

Palynology is not only a scientific discipline in its own right, but also a subdiscipline within pollen analysis and aerobiology. Pollen and spores are frequently dispersed from their points of origin and carried on wind e

Fig. 2.2 Present day Date Palm (Phoenix dactilifera).

currents thus forming a component, the biospora of particulate matter in the air. Pollen and spores may be considered as 'organic pollutants' in air.

Pollen grains are microspores, which carry the male genetic component gametes of the plants, which produce them. Pollen grains are essentially part of the sexual reproductive process, spores, by contrast, may be the product of a sexual process, or may be vegetatively produced, the latter having the function of spreading the species which produce them-an aspect known as vegetative or asexual reproduction. Palynology as a modern scientific discipline is not old although the interest in and study of small biological particles such as spores and their possible role in the life of plants, extends back to at least classical times.

Fig. 2.3 Artificial pollination of Date Palm (Phoenix dactilifera) by a Japanese scientist at the present time.

The scientific study of pollen, both structure and function, has its origin in the early part of the 20th century. The establishment of a methodology to record both quantatively and qualitatively, the occurrence of pollen was first published in 1916 by Lennart von Post, a Swedish botanist (von Post, 1916). This method of illustrating the spore content of peat cores, later ice and submarine seabed cores, has become a standard method involving not only pollen and spores but also micro faunal and mineral deposits.

Contemporary pollen, which descends under gravity or is washed down by rainfall is called 'pollen rain'. All surfaces receive the descending pollen, which become buried in soil or sink to the bottom of lakes, rivers, seas and soil. Pollen in the air is also recovered from the groomed surfaces of fauna and can be extracted from the faeces enabling the scientist to determine diet and or habitat (Caulton 1988; Caulton et al, 2005). Fossilized dung of bats inhabiting in caves has revealed similar indicator pollen of diet from the Pleistocene period.

PROFESSOR GUNNAR ERDTMAN

He was one of the foremost palynologists of the world in the 20th century and rendered valuable service to the science of palynology, particularly in pollen morphology. He started his work in pollen analysis in the footsteps of Professor Lennart von Post, the inventor of the method of pollen analysis of peat bog for reconstruction of past vegetation. Erdtman worked in the summers of 1918-1920 and 1922 as a member of the peat bog investigation team of the Geological Survey of Sweden. He contributed significantly to trends of post-glacial forest history of Western Europe. In 1930-1931 he earned the Rockfeller Scholarship to work on pollen analytical work in Western Canada and visited several parts of the U.S.A., including California and Arizona.

Later, Erdtman concentrated on experimental work on pollen, which resulted in 1934 (Erdtman 1934) in the invention of the Acetolysis technique for the preparation of pollen for microscopic studies.

In 1950 at the International Botanical Congress in Stokholm, Sweden, he organized the first International Palynological Meeting. At the 1954 International Botanical Congress in Paris, for the first time, a special section was devoted to palynology with Professor Gunnar Erdtman as its President.

Swedish Natural Science Research Council in 1948 established the famous Palynological Laboratory at Stokholm, Bromma and later at Solna. Prof. Erdtman was appointed as its Director. In addition, he also served as Professor of Geological Palynology at the University of Stokholm. He published more than 250 original research papers and several books dealing with palynology. One outstanding book entitled 'Pollen Morphology and Plant Taxonomy' was published in 1952, the other important book published by him in 1969 was 'The Handbook of Palynology' which has served as a standard manual for a long time.

Professor Erdman's other significant publications include; 'Grana Palynologica' (9 Vols. 1954-1909), 'An Introduction to a Scandinavian Pollen Flora' Vol. I in 1961, II in 1963 and 'World Pollen Flora'. He presented papers and conducted short-term courses in palynology in more than 60 universities all over the world.

Professor Gunnar Erdtman 1897-1973

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