The main difference between bryophytes and pteridophytes is that the plant body of. The primary components of stele are xylem and phloem. The name stele has been derived from greek word meaning pillar or column. As they produce neither flowers nor seeds, they are referred to as cryptogams. The plant list includes a further 3,533 scientific plant names of infraspecific rank for the pteridophytes. A pteridophyte is a vascular plant with xylem and phloem that disperses spores. Evolution of the conducting tissue in pteridophyta. In this article we will discuss about the evolution of stele in a plant. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as cryptogams, meaning that their means of reproduction is hidden.
To collect spores for each species, it is crucial to know the season in which spores typically mature. Stellar evolution is the process by which a star changes over the course of time. The petioles and rhizomes of the fern dryopteris outcomes a vermifuge drug. The table shows the lifetimes of stars as a function of. Dec 08, 2017 for the love of physics walter lewin may 16, 2011 duration. The structure and function of xylem in seed free vascular plants. Pteridophytes biology encyclopedia plant, body, different. They are preserved in the form of fossils or coal deposits. Pteridophytes general characters and life cycle of ferns email.
The body of the sporophyte is well differentiated into roots, stem and leaves. They formed the dominant part of the earths during palaeozoic and mesozoic periods. Economic importance of pteridophytes homework help. In a book of this limited size it is impossible to describe in detail all the fossil plants that are known. Species of pteridophytes contained within the plant list belong to 35 plant families and 568 plant genera. Pteridophyta is the most highly evolved group among the cryptogams. Stelar theory also says that the cortex and the stele are the two fundamental.
For the love of physics walter lewin may 16, 2011 duration. 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. Pteridophytes introduction, authors and addresses, systematic list, glossary, and key to tribes. Although this particular topic is beyond the aims of the present paper, let us remember that these tissues conditioned all tracheophyte sporophyte evolution. Find powerpoint presentations and slides using the power of, find free presentations research about pteridophytes ppt. Useful notes on the classification of pteridophytes. Stelar evolution in pteridophytes ppt types of steles and its evolution in pteridophytes ppt what is stele. A few pteridophytes are aquatic while still others are. 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. Some of the most important types stelar system in ferns are as follows. The stele is a real entity and present universally in all axis of higher plants. The following separation of the main growth forms of pteridophyta is proposed.
Sporophytes diploid phase the main plant body is a sporophyte which is differentiated in to root, stem, rhizome underground stem and leaves. Jeffrey 1898, for the first time pointed out the stelar theory from the point of view of the phylogeny. Thus the stele is defined as a central vascular cylinder, with or without pith and delimited. Most pteridophytes are terrestrial plants and thrive well in abundant moisture and shade while some flourish well in open, dry situations especially in xeric conditions. Accordingly several major groups of vascular plants, many minor groups and a large number of genera have had to be omitted.
Firstly all the botanists divided the plant kingdom into two large groups cryptogamia and phanerogamia, linnaeus 1754 used the term cryptogams for the first time for those plants which did not possess visible sex organs. Molecular evolution of pteridophytes and their relationship to seed plants. They are psilopsida, psilotopsida, lycopsida, sphenopsida, pteropsida and progymnospermopsida. In a vascular plant, the stele is the central part of the root or stem. For the first time, the stelar organisation appeared in pteridophytes. Ferns may exhibit any one of three types of siphonostele. In 1880, the cryptogams of the plant kingdom were divided.
According to him, the primitive type of stele is protostele. From wikieducator in this article we will discuss about the evolution of stele in a plant. The modern classification of pteridophytes have been suggested by many scientist according to the sporne1975 pteridophytes have been classified into six classes. Tissues like pericycle, medullary rays and pith are also the components of stele. Types of stelar systems and its evolution in pteridophytes and. Ferns, horsetails often treated as ferns, and lycophytes clubmosses, spikemosses, and quillworts are all pteridophytes.
In addition, the location, microhabitat, and sporophyte age affect the timing of spore maturation. Pteridophyta characteristics, life cycle, classification. Life forms of pteridophyta, their origin and evolution. Stelar theory, components of stele, different types of steles in plants, protostele. Most pteridophytes have underground stems parallel to the substrate called rhizomes. This pdf version does not have an isbn or issn and is not therefore effectively published melbourne code, art. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. For example, the primary vascular system neither fits with current concepts of stelar evolution or. The plant list includes 46,428 scientific plant names of species rank for the pteridophytes.
This type is found in primitive fossils and living ferns. Fronds in the largest species of ferns can reach some six metres in length. Gemetophyte development homosporous and heterosporous ferns. Hence the pteridophytes are called as first vascular plants. 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.
Jeffrey 1902, 1910, and 1917 interpreted the evolution of the siphonostele from the. Ferns are grownup as ornamental plants for their stunning fronds. View and download powerpoint presentations on pteridophytes ppt. On natural classification of the family polypodiaceae. Van tieghem and douliot 1886 interpreted the plant body of a vascular plant in the different way.
Do you have all your important documents in one place in case of an emergency. The evolution of stele in pteridophytes and higher plants. Occurrence and evolution of pteridophytes biology boom. The degree of spore maturation can be estimated by spore color, nucleus position, and vacuole size.
Distribution, general characteristics, classification and phylogeny. The printed version, however, was effectively published on 6 june 20. The appearance of true water and foodconducting tissues in pteridophytes represented an event of enormous consequences for the evolution of land plant sporophyte. This hypothesis of stelar evolution is at variance with that of jeffrey. Xaxim is a type of pteridophyte with an aerial stem that is generally perpendicular to the soil and from which hundreds of roots arise to absorb water from the environment. Each of these can be divided into life forms according to a series of morphological and other characters. Late paleozoic regarded as the age of pteridophyta. According to the older botanists, the vascular bundle is the fundamental unit in the vascular system of pteridophytes and higher plants. Pdf difference between bryophytes and pteridophytes.
A few pteridophytes are aquatic while still others are epiphytes. A concept based exclusive material pteridophytes, gymnosperms. The sporophyte was the dominant phase of the life cycle of these early pteridophytes. The pteridophytes are an economically important group of plants. In protostele, the vascular tissue is a solid mass and the central core of the xylem is completely surrounded by the strand of phloem. It is speculated that life began in the oceans, and through millions of years of evolution, life slowly adapted on to dry land.
A good portion of the image references used here tap fine image resources for nonflowering vascular plants. Slade department of botany, university of otago, dunedin, new zealand received 16 april 1971 summary recently namboodiri and beck 1968c and beck 1970 in proposing a new hypothesis of stelar evolution in the gymnosperms failed to mention its possible application to angiosperms. Bower, the development of the stele structure in plant evolution paralleled the. The different species of selaginella are grown as the garden plants. Seed plants include the angiosperms, the conifers, and a smaller assortment of other plants. The stele and the leaf trace anatomy are unique among the ferns. They formed the dominant part of the earths during palaeozoic and mesozoic periods on soral evolution. Stelar evolution of pteridophytes, sporangial organization homospory and heterospory. Pteridophytes pteridophytes is a general term for the vascular, free. Pteridophytes may represent the closest living relatives sister group to the seed plants. Stelar evolution in pteridophytes linkedin slideshare.
Pteridophytes or pteridophyta, in the broad interpretation of the term, are vascular plants plants with xylem and phloem that reproduce and disperse via spores. The first vascular plants rapidly diversified to cover the earth. Share your knowledge share your word file share your pdf file share your ppt file. The term stele refers to the central core of plant axis and is restricted only to primary tissues. The pteridophytes ferns and fern allies pteridophytes are vascular plants and have leaves known as fronds, roots and sometimes true stems, and tree ferns have full trunks.
Pteridophytes are herbaceous except a few tree fern. Life cycles of lycopodium, selaginella, equisetum, adiantum and marsilea. Unlike the bryophytes, these plants are in the mainstream of land plant evolution and eventually gave rise to the seed plants. Occurrence and evolution of pteridophytes with its origin and economic importance in pteridophyta is a group of ancient plants.
And among the first of the plants to truly live on land were the pteridophytes. The evolution of xylem was critical to the success of embryophytic land plants. Unlike the bryophytes, these plants are in the mainstream of land plant evolution and eventually gave rise to the seed. Coordinate terms for subtypes are presented, in particular for parts iabc, ia6. The origin and early diversification of land plants marks an interval. Pdf stelar morphology and the primary vascular system of seed. Pteridophytes or pteridophyta, in the broad interpretation of the term or sensu. Primitive siphonostele protostele with central pith. Basic types of steles protostele central xylem, surrounding phloem. Stele greek word meaning a column can be defined as the unit of vascular system that is made up of xylem, phloem, interfascicular tissues, medullary rays, pericycle and pith if present. Pteridophytes ferns and fern allies the plant list. Different types of steles present in pteridophytes and its evolutionary significance.
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