Combining these observations, we suspect that the trigger. Pteridophytes may represent the closest living relatives sister group to the seed plants. Hfecycle, come the group of plants known as pteridophytes. Pdf emergence of apospory and bypass of meiosis via apomixis. Apospory is the development of gametophyte directly from sporophyte without formation of spores. The gametophytes of bryophytes, and less commonly ferns and lycopods can develop a group of cells that grow to look like a sporophyte of the species but with the ploidy level of the gametophyte, a phenomenon known as apogamy. Pteridophyta in the broad interpretation of the term are. Megasporophyll of pteridophytes is comparable to which structure of angiosperms stamens ovule carpel microsporophyll. It is now generally believed and accepted that life has existed on earth for over 3000 million years. Classification of pteridophyta linkedin slideshare.
Endosperm formation in aposporous crataegus rosaceae. Selaginella, pteropsida, pteris,marsilea, apogamy, apospory, reproductive biology. Nevertheless, some clarifications are needed on the phenomena of apogamy and apospory mentioned above, on a possible morphological and anatomical similarity and independence between gametophyte and sporophyte of the first land plants, supported by recently discovered fossil gametophytes of lyonophyton rhyniensis. A pteridophyte is a vascular plant with xylem and phloem that disperses spores. The pteridophytes are an economically important group of plants.
Another difference between pterophyta and higher plants is that many species belonging to the pterophyta have a vegetative 1 sorus plural sori. The phenomena of apogamy and apospory have always been regarded as short cuts in the life history of ferns, and the fact that apparently either generation. Variation in the number of sperm that combine with the central cell has also. Comparative morphology, reproduction and phylogeny of following orders with. Both apospory and apogamy are considered as the abnormalities of plant. The vegetative reproduction is also a common type of reproduction in the pteridophytes. In bryophytes and pteridophytes, a gametophytic phase may begin without meiosis by apospory. Botany for degree pteridophyta top results of your surfing botany for degree pteridophyta start download portable document format pdf and ebooks electronic books free online rating news 20162017 is books that can provide inspiration, insight, knowledge to the reader. Cytological and reproductive studies of japanese diplazium woodsiaceae. Affinities of pteridophyte with bryophyte and algae. It is even suggested as normal phenomenon in pteridophytes.
It is also advantageous since it can produce large number of individuals which are genetically. Multiple choice quiz on pteridophytes biology multiple. Many pteridophytes supplement their sexual cycles with various forms of vegetative reproduction yatskievych 2003. This usually occurs when damage to a plant in the sporophytic phase leads directly to the growth of a plant that is in the gametophytic phase but bears the chromosome complement that would normally be found in the sporophytic phase. Botany the development of an embryo of a flowering plant outside the embryo sac, from a cell of the nucellus or chalaza. Professor farmer and miss digby have published the results of their studies of apogamy and apospory in ferns. Apogamy is the development of an unusual haploid sporophyte from the gametophyte without the fusion of gametes. The book also discusses topics like heterospory, seed habit, leaf phylogeny, stellar system, alternation of generations, regeneration in general and special role of germ cellsegg and sporein life cycle. Read the introductory remarks and list of characteristics of the bryophytes p. 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 two main vascular elements are the xylem and phloem. This is made apparent by the phenomena of apogamy and apospory, cases of which have been recorded many times in pteridophytes since they were first observed in 1874. For most of this time it was restricted to water where it flourished and evolved.
Ebook botany for degree pteridophyta as pdf download. Ebook an introduction to pteridophyta as pdf download. Issues and applications is nominally about ferns, but it is more than that. Apospory definition is production of gametophytes directly from diploid cells of the sporophytes without spore formation as in certain ferns and mosses. Pteridophytes biology encyclopedia plant, body joilethbwinmi. On the basis of their anatomy jeffrey in 1902 divided the vascular plants into two types or stocks. Apospory is the development of 2n gametophytes, without meiosis and spores, from vegetative, or nonreproductive, cells of the sporophyte.
Characteristics of pteridophytes, morphology of pteridophytes, reproduction of pteridophytes, homosporous and heterosporous pteridophytes, megaspore and microspores, gametophytes of pteridophytes, fertilization, zygote and embryo of pteridophytes. The sporophytes of plants of these groups may also have the ability to form a plant that looks like a. Ferns, horsetails often treated as ferns, and lycophytes clubmosses, spikemosses, and quillworts are all pteridophytes. Diversity of pteridophytes in india and their migration to land. In contrast, apogamy is the development of 1 n sporophytes without gametes and syngamy from vegetative cells of the gametophyte. Apospory in pteridophytes pdf the investigations in pteridophytes probably of most interest and importance ing of apogamy and apospory, it is important to define these terms at the. For students and researchers these papers are seminal. Some pteridophytes are aquatic marselia, azolla and some are epiphytes ophioglossum pendulum. Formation of sporophyte from a vegetative portion of prothallus without sexual fusion is called apogamy apospory apomixis apocarpy. Review of literature please purchase pdf split merge on. The pteridophytes reproduce both by the vegetative and sexual methods vegetative reproduction.
The xylem consists of mostly, tracheitis and rarely, vessels selaginella, pteris etc. Thus, free water is not required for swimming sperm. It helps to increase the number of population under unfavourable conditions also. Natural apogamy is common in ferns like dryopteris, adiantum, osmunda, pteris etc. Steil with plates xvi, xvii, and four figures historical although apospory was discovered in the mosses by pringsheim i8 and stahl iv a short time after apogamy had been found in pteris cretica albolineata by farlow ii, apospory remained unknown in the pteridophytes until druery 6, 7 reported the. This life cycle is also believed to foster quick reproduction in connection with brief damp periods. Buy isbn9781403930309 at 16% discount by macmillian india ltdnew delhi. Pteridophytes general characters ppt general characteristics, life cycle and reproduction of pteridophytes ppt what are pteridophytes. Apogamy, apospory, and parthenogenesis in the pteridophytes. Apogamy, apospory, and parthen ogenesis in t he pteridophytes w.
Apogamy is the development of a sporophyte directly from the gametophyte without the intermediate formation and fertilization of gametes. Apogamy, apospory and parthenogenesis in the pteridophytes. What is apogamy and apospory biology plant growth and. The different species of selaginella are grown as the garden plants. Apogamy is a type of plant reproduction in which sporophyte diploid phase is produced from the gametophyte haploid phase without fertilization. Probably when i provided them with arbeitsbescheinigung, salary slips, social security statements from germany, they are convinced that i worked in munich. Seed habit originated in algae fungi bryophytes pteridophytes. Bell botany department, university college, london w. Developmental biology 23, 550562 1970 the fine structure of fern root cells showing apospory marian h. Apospory and apogamy in pteridophytes biology discussion. Gamma radiationinduced in vitro hormetic apogamy in the. Summary apomixis in crataegus is primarily aposporous and. The pteridophytes ferns and fern allies pteridophytes are vascular plants and have leaves known as fronds tertium organum pdf portugues, roots and sometimes true stems.
Emergence of apospory and bypass of meiosis via apomixis after sexual. Altmetric apogamy, apospory, and parthenogenesis in the. Botany botany development of the gametophyte from the sporophyte without the formation of spores. Maakt het mogelijk om pdfbestanden samen te voegen met een simpele drag anddrop interface. 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. Experimental studies described in the book highlight the phenomena of apogamy and apospory, their occurrence, induction and alternate role in life cycle. Seed plants include the angiosperms, the conifers, and a smaller assortment of other plants. Pdf hybridisation and polyploidy are major forces contributing to plant speciation. Induced apospory had previously been obtained by goebel 1907 in detached sporeling leaves of a number of different species of ferns includ ing osmunda. Apospory is the development of unusual diploid gametophyte from the vegetative parts of sporophyte and not from the spores. Prothallus gives rise to sporophyte without fertilization.
Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as cryptogams, meaning that their means of reproduction is hidden. Observations on the inheritance of apospory and alternations of generations. Classification of pteridophytes for a long time the division pteridophyta includedthe ferns, lycopods and horsetails. Apospory definition of apospory by the free dictionary. However, apospory and apogamy are independent and not related to each other steil, 1939. The cause of apospory involves deficiency of mineral nutrition, development of leaves under dim light etc. The fine structure of fern root cells showing apospory. All the pteridophytes possess a vasculature in the center of the axis traversing from one and to the other and branching with all the branches.