Telome concept and its significance in the origin of different groups of pteridophytes. Many pteridophytes supplement their sexual cycles with various forms of vegetative reproduction. According to telome theory the earliest levees are flattened telomes or phylloids, and the sporangium in all cases, together with its stalk or sporangiophore, is a fertile telome. Ethnobotanical studies of 40 pteridophytes species by uddin et al. Most of the pteridophytes ferns and fernallies show their luxuriant and vigorous growth during the rainy season particularly in the hilly regions usually above 1400 m altitude. Compound sporangiophores, like those of equisetum, are syntelomes. The diploid sporophyte plant that produces tiny, microscopic spores and the haploid gametophyte plant that produces eggs and sperms when an egg is fertilized by a sperm, the fertilized egg, now again diploid grows into a new sporophyte plant. Charan singh university,meerut distribution of marks. Pteridophyta teridafata os made from two greek roots that mean winged pteryz.
When you think of forests and woods, you can picture trees, abundant lush green ferns, and other plants. The entire vascular cylinder of the primary axis of pteridophytes is usually referred to as stele. Structural features, geological distribution and evolutionary significance of 3. Pteridophyte definition of pteridophyte by merriamwebster.
He has made several important contributions in the fields of historical linguistics and evolutionary sociopolitics as well. Concept of telome theory origin of sporophylls in lycopsida planation of the fertile and sterile telomes reduction of the mesomes and in number of spornagia protolepidodendron and psilotum like axillary sporangia and single veined leaves are evolved. A pteridophyte is a vascular plant with xylem and phloem that disperses spores. Felix bast is a molecular phylogeneticist, polar explorer, natural historian and a science communicator based in india.
To demonstrate sufficient knowledge of the concept of the fossil plants. Pteridophytes may represent the closest living relatives sister group to the seed plants. The first vascular plants rapidly diversified to cover the earth. Pteridophyta is the most highly evolved group among the cryptogams. Sporangium development eusporangiate type and leptosporangiate type. They also studied the use of pteridophytes as a vegetable and herbal medicine. In other words, gymnosperms are naked seeded plants.
Leaf gaps are small areas above the node of some leaves where. Pteridophytes are a group of primitive land plants belongs to the cryptogams. Such an explanation is opposed to the widely accepted concept of. Zimmermanns telome theory has been widely accepted for over seventy years as the leading explanation for this evolutionary innovation. This pdf version does not have an isbn or issn and is not therefore effectively published melbourne code, art. Some pteridophytes are aquatic and some are epiphytes. Pteridophyta characteristics, life cycle, classification. The plant body of bryophytes is more differentiated than that of algae. The modern classification of pteridophytes have been suggested by many scientist according to the sporne1975 pteridophytes have been classified into six classes. Sumita, assistant professor, department of botany, pggc11, chandigarh. Pteridophytes biology encyclopedia plant, body, different. Before, they are in the haploid gametophyte stage which is called prothallus for a fern.
The sporophyte is the conspicuous and familiar plant body. Seed plants include the angiosperms, the conifers, and a smaller assortment of other plants. This is a simple concept and explains most of the morphological problems about different organs of a plant. Rhyniophyta, trimerophytophyta, zosterophylophyta, lepidodendron, lyginopteris. Some other uses are ferns provide natural vegetation thats important to both wildlife and birds. The telome theory can be applied to interpret the evolution of a synangium of psilotum. International research botany group 2017 international. On leafarchitecture as illuminated by a study of the pteridophyta. Some of the characters of pteridophytes are as follows.
Various animals use the fronds as food while birds and small creatures use the plants for cover. Telome and the evolution of the independent sporophyte among pteridophytes. Gymnosperms economical and ecological values albuerolyka. Range of structure, reproduction and evolution of the gametophytes sex organs. Unlike the bryophytes, these plants are in the mainstream of land plant evolution and eventually gave rise to the seed plants. Reproduction in psilotum with diagram pteridophytes. Pteridophytes constitute a significant and important group in the plant kingdom. Pteridophytes transition to land megaphylls equisetales. Although the ovules are naked at the time of pollination, the seeds of gymnosperms are sometimes enclosed by other sporophyte tissues by the time they are mature. According to zimmermann, these telomes or telome trusses of primitive rhynia type of vascular plants have been subjected to certain evolutionary processes in varying degrees among the various taxonomic groups. Pteridophyte reproduction christian brothers university. In plant anatomy and evolution a microphyll or lycophyll is a type of plant leaf with one single, unbranched leaf vein. They play an important role in plant succession on bare rockssoil.
Merits and demerits of telome theory biology 840 words. There will be three groups consisting of algae, mycology and phytopathology and microbiology. Plants with microphyll leaves occur early in the fossil record, and few such plants exist today. Pteridophytes or pteridophyta, in the broad interpretation of the term, are vascular plants plants with xylem and phloem that reproduce and disperse via spores. Pteridophytes were dominant land plants during the carboniferous era and a major source of todays coal and oil. Pteridophytes spend the largest amount of therif lifecycle in the state of the sporophyte. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as cryptogams, meaning that their means of reproduction is hidden.
Pteridophyta is designed to fulfill the needs of undergraduate and postgraduate students of botany. Concept of icbn b salient features of botanical nomenclature c ranks and nomenclature of taxa d typification e rules of priority f. This page was last modified on 26 december 2014, at 03. Pteridophytes general characters and life cycle of ferns email. Bryophytes were a pivotal step in land plant evolution, and their significance in the regulation of ecosystems and the conservation of biodiversity is becoming increasingly acknowledged. Sharma 2000 reported the ethnobotanical uses of ferns from rajasthan, india. The telome theory, largely founded upon paleobotanical evidence, has been accepted as a working hypothesis by many morphologists and paleobotanists concerned with. Click here to learn the concepts of silent features of pteridophytes from biology. Study of morphology, anatomy and reproduction of psilopsida, lycopsida and pteropsida. Besides having various medicinal properties, the pteridophytes are also employed for a variety of commercial and environmental purposes.
These arc standard parts rhat were first observed in fossils. Pteridophytes pteridophytes is a general term for the vascular, free. According to telome theory, in a fertile telome truss the usual processes of overtopping, planation and syngenesis resulted in the formation of a web like sporophyll with the sporangia borne at the tips of veins in the margin of the lamina fig. Abstract the telome theory states that the organs, appendages and vascular systems of land plants evolved from simple multicellular modules telomes that have been combined and modified in various ways. Pteridophytes general characteristics general characters of pteridophytes the vascular cryptogams pteridophytes are plants with feather like leaves. With the commencement of monsoon about mid june, the ferns and fernallies start growing vigourously and luxuriantly. In view of the coronavirus pandemic, we are making live classes and video classes completely free to prevent interruption in studies. But trust me the first thing that you notice is the abundant foliage of fern plants. A concept based exclusive material pteridophytes, gymnosperms. Besides xylem and phloem, it includes pith if present and is delimited from the cortex by the pericycle. Plants, land plants, embryophytes cutile more or less diploid embryo develops within protective maternal haploid tissue. The telome concept has been used in understanding the origin and evolution of the following major groups of plants. The telome theory, largely founded upon paleobotanical evidence, has been accepted as a working hypothesis by many morphologists and paleobotanists concerned with vascular plants other than the angiosperms.
Content is available under the creative commons attribution share. Bryophytes are also called amphibians of the plant kingdom because these plants can live in soil but are dependent on water for sexual reproduction. The different species of selaginella are grown as the garden plants. To apply biological principle and concept to everyday life, especially to matters affecting living things, the environment and economy. This page was last modified on 26 december 2014, at 02. They are psilopsida, psilotopsida, lycopsida, sphenopsida, pteropsida and progymnospermopsida. The telome theory challenged this morphological trinity by beginning an analysis of. These ferns, in biological terms, are nothing but the pteridophytes, belonging to the division pteridophyta of the plant kingdom. Therefore pteridophytes are no longer considered to form a valid taxon, but the term is still used as an informal way to refer to ferns, horsetails, clubmosses and whisk ferns. Pteridophytes introduction, authors and addresses, systematic list, glossary, and key to tribes.
Candidates shall be required to answer five questions selecting at least one from each group. The printed version, however, was effectively published on 6 june 20. Using the telome mesome distinction, and the concept of universal elementary processes underlying the change in form in all plants, the theory was an ambitious synthesis based on the proposition that evolutionary change might be understood by a simple set of developmental or evolutionary rules. Oct 19, 2015 gymnosperms came from the greek root gymnos or naked with spermaor seed. Some pteridophytes are aquatic marselia, azolla and some are epiphytes ophioglossum pendulum. The sporophyte was the dominant phase of the life cycle of these early pteridophytes. Botany pteridophytes class notes for students and teachers of life science biological science. The phylloids are the prototypes of the microphyllous foliage leaves. Pteridophytes ferns and lycophytes are freesporing vascular plants that have a life cycle with alternating, freeliving gametophyte and sporophyte phases that are independent at maturity. The steps leading to the formation of a megaphyll are given in figure 11. Most pteridophytes are terrestrial and grow in moist and shady places while some flourish well in open, dry places especially in xeric conditions. Mar 23, 2018 the pteridophytes are an economically important group of plants. Pteridophyte definition is any of a division pteridophyta of vascular plants such as a fern that have roots, stems, and leaves but lack flowers or seeds. Despite early success in pteridophytes and gymnosperms, the telome theory never.
The telome is the fundamental supercellular building block in plants. Reproduction in psilotum with diagram pteridophytes botany. It envisages that firstly, instead of the primitive equal dichotomous branching of the stem, there developed a main axis with lateral side branches. General characteristics of pteridophytes key points easy.
This is a portion of the telome theory as proposed by zimmermann 1952 and 1959, who proposed that all of the main plant organs can be derived from simple rhynialike axes called mesomes sterile axes and telomes fertile axes. Silent features of pteridophytes definition, examples. The telome concept is also involved in a bizarre classification by lam 1948, 194748 of the cormophyta into two large groups, the stachyosporae, in which the sporangia are essentially terminal on fertile telomes, and the phyllosporae, in which. And among the first of the plants to truly live on land were the pteridophytes. It is speculated that life began in the oceans, and through millions of years of evolution, life slowly adapted on to dry land. According to telome theory first proposed by zimmermann 1930, 1938, primitive pteridophytic shoot was naked and dichotomously branched. Pdf on apr 18, 2002, paul kenrick and others published the telome theory find, read and cite all the research you need on researchgate. Jan 23, 2017 occurence most of the pteridophytes are terrestrial and grow in moist and shady places while some flourish well in open, dry places especially in xeric conditions selaginella lepidophylla. They usually occur in damp, humid and shaded localities.
Classification of pteridophytes as proposed by sporne 1975. This gametophyte is really small and produced the gametes for the later fertilizaion to build the sporophyte. The pteridophytes are an economically important group of plants. Buy isbn9781403930309 at 16% discount by macmillian india ltdnew delhi. This theory is based on fossil record and synthesizes the major steps in the evolution of vascular plants. The branching of the rhizome and formation of adventitious buds on rhizomes is. Ferns, horsetails often treated as ferns, and lycophytes clubmosses, spikemosses, and quillworts are all pteridophytes. Many pteridophytes supplement their sexual cycles with various forms of vegetative reproduction yatskievych 2003. The true story seems to be lost in antiquity and perhaps will never. As in seed plants, the greatest diversity of pteridophytes is found in the tropics, with only about six hundred species adapted for life in temperate climates. The current trends in the subject are explained in a simple, lucid and understandablewriting style. As they produce neither flowers nor seeds, they are referred to as cryptogams.
Alternation of heteromorphic multicellular generations. Extant pteridophytes are cosmopolitan but are much better represented in the humid tropics, with only a few families e. The contents duly unitwise and contents in such manner so that duc importanceis given to requisite laboratov skills. According to bierhorst 1971 this theory is too simple and too easily applicable but unfortunately its excessive use has greatly diminished its value. According to the telome theory,the polystelic condition, such as found in the stem of selaginella, has developed due to syngenesis and siphonostelic and actinostelic conditions are supposed to be the products of tangential or redial fusion of vascular systems of polystelic axis. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Stout aerial branches bear large conspicuous sporangia fig. They are the first evolved plant group with vascular tissue system for the conduction of water and food materials.
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