Palynology in plant classification:
The study of pollen and spores is called Palynology. The shape and symmetry of pollen grain, the architecture of its wall, exine stratification, sculpture and structure, and types, number, position, shape, and structure of its aperture are some of the basic characters which prove useful at all taxonomic levels.
The study of pollen and spores is called Palynology. The shape and symmetry of pollen grain, the architecture of its wall, exine stratification, sculpture and structure, and types, number, position, shape, and structure of its aperture are some of the basic characters which prove useful at all taxonomic levels.
Palynological characters have been used in solving several taxonomic problems, including the reposition of several disputed taxa, and interpretation of problems relating to the origin and evolution of different groups and several other workers have made the exclusive use of pollen characters in providing the classification of angiosperms.
The classification of pollen is based on the number, position, character, analysis called the NPC system.
Role of Palynology :
(a) According to Meyer (1975), Angiosperms contain columnar or granular ektexine and nonlaminated endexine, whereas Gymnosperm contains alveolar or granular ektexine and laminate endexine.
(b) A massive exine and thin intine are present in angiosperm pollen. But in certain taxa among monocots, the exine is highly reduced and intine is well developed.
(c) Several angiospermic taxa have distinctive pollen types. Gramineae have smooth sulcate pollen, Malvaceae and Compositae have typically spinulose exine.
(d) Pollens are binucleate in Magnolidae and trinucleate in Caryophyllidae.
(e) The exine pattern is useful in recognizing different species of a genus
(f) Phylogenetic relationships are determined using pollen characters in several cases. Genus Cicer is usually placed under the tribe Viceae of Papilionaceae. Palynological studies of Cicer suggest that it is more close to the tribe on ononideae and should be transferred from Viceae to Ononideae
(g) Pollen grains are associated with tetrads in several families of dicots and monocots.
(h) Palynological evidence has supported the separation of Paeoniaceae from Ranunculaceae and Bombaceae from Malvaceae
(i) Pollen characters prove useful in distinguishing the genera Salix and Populus of Salicaceae.
(j) Palynological studies suggested that Thumbergioideae of Acanthaceae should be given a family status.
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