9. Content Guidelines 2. It is coriaceous, reniform to orbicular, compressed, 1-celled and dehiscing by a split down the apex from end to end. Plants homosporous, leaf 1-2 pinnate, sporangia in sori on the ventral side of the leaf, sporangia with indusium, sporangial development mixed. (Fig 6.26). It consists of annular and spiral tracheids. Some of microgametophytes shift down between the sporophylls and may fall into the partly opened microsporangia. 1. Stem axis condensed rhizomorph like, leaves microphyllous and ligulate, heterosporous without strobiloid organisation. 6.3.1: Lycopodiopsida - Biology LibreTexts Opposite each ridge is a vascular bundle of unusual interest. Give an example. Habit The plant body of Selaginella is sporophyte (2n) and it is differentiated into root, stem, and leaves (Figure 2.25). The Strobilus Theory It was put forth by Bower in 1894 and supported the origin of sporophytes of vascular cryptogams from the liverworts. But in species like E. sylvaticum, a layer of inner endodermis is also present (Fig. 15. 7. They are slightly raised and ex-indusiate. Each sporangium, which dehisces by means of a terminal slit, produces numerous tetrahedral spores (Fig 6.15). Sporangia borne on a long inframarginal commissure, sporangia borne in round to elongate sori, immature sori covered by stalked, peltate, roundish paraphyses ; spore ellipsoidal, monolete. Sori are roundish and borne on the veins. A T.S. Sporangia are grouped together into distinct elongated sori. In general, the plants are herbaceous, erect or pendent. Our editors will review what youve submitted and determine whether to revise the article. Annulus is vertical in position. Margin of the fertile segment modified as an indusium, sporangia distant on the veins of the unipinnate fertile lamina. Image Guidelines 4. Each leaf has two lobes. The cookie is used to store the user consent for the cookies in the category "Performance". It bears trichomes and a few to many fibrous roots. The sporangium is surrounded by jacket and tapetal layers which enclose many spores. Plant body differentiated into rhizomatous stem, leaf and root, leaf megaphyllous, sporangia aggregate on the leaf margin as sori. Sporangia are of two types mega-sporangium bears single, ellipsoidal megaspore with an apical papilla like laesura and papillate surface; microsporangium bears many small, spheroidal, trilete microspores with rugulose surface. Plant body differentiated into rhizomatous stem, leaf and roots, leaf megaphyllous, sporangia aggregate mostly on the leaf margin as sori. Lamina is unipinnate and glabrous with free veins. Xylem is exarch (Fig 6.34). All three are typically dioecious, although some Ephedra species exhibit monoecy. What would be the consequences if there is no meiosis in organisms that reproduce sexually? Magnolia has a particularly strobiloid flower with all parts arranged in a spiral, rather than as clear whorls. Submerged leaf is modified into numerous root-like filaments with multicellular hairs. of the internode of a mature stem reveals a protoxylem lacuna (carinal canal) associated with a vascular bundle. The cookies is used to store the user consent for the cookies in the category "Necessary". This website uses cookies and third party services. Several leaves develop spirally from the top. A strobilus is composed of leaves called sporophylls that bear sporangia (Figure \(\PageIndex{4}\)). A T.S. Study the external features of cone, cut its transverse and longitudinal sections, stain in safranin, mount in glycerine and study. xylem element, are arranged in more or less parallel plates with the phloem in between these patches. Get complete information on the Reproduction in Pteridophytes Leaves alternate, bilobed, long; sporocarp dimorphic. Antherezoids are produced in antheridium and are large spirally coiled and bears numerous large flagella. Before uploading and sharing your knowledge on this site, please read the following pages: 1. The central stem produces bracts and in the axil of each bract is a cone scale. Anatomy of Equisetum (With Diagram) | Pteridophyta - Biology Discussion Sori develop on marginal commissure; margin of the fertile segment modified as indusium; sporangia contiguous in compact groups. Ridges and grooves are not so much well-marked as in sterile shoot. The incidence. 4. Each vascular bundle is conjoint, collateral, closed, and consists of xylem, phloem and some parenchyma. 239 E, F). The xylem consists of protoxylem and metaxylem with the former being exarch and consisting of spiral or annular tracheids, and the latter consisting of scalariform tracheids. ex. Why do you think that carbohydrates are not digested in the stomach? Our mission is to provide an online platform to help students to share notes in Biology. Leaves are dimorphic. Archegonium is flask shaped and contain egg, ventral canal cell and neck cancel cell. Both kinds of spores are embedded in massulae (Fig 6.37). 3. Content Guidelines 2. This cookie is set by GDPR Cookie Consent plugin. Each spore has a triradiate ridge (Fig. Stem is short to long, creeping, slender and frequency branched. There are four longitudinal air chambers running along the whole length of the acicular part. The stem is short and 2-3 lobed, corm like structure which is covered by long, stiff, awl-shaped leaves. Ophioglossum 7. Spores are elliptical, monolete, slightly papillate to smooth and homosporous (Fig 6.22). 4. This cookie is set by GDPR Cookie Consent plugin. (Fig 6.24). The lower portion of rachis is paleaceous, i.e., covered by numerous brown scales called ramenta. Lamina entire sori 1-2 nerved, laterally elongated, indusiate. Which types of bacteria are used in Bt-cotton? Sporangia and paraphyses are grouped together in each sori. Stem creeping, slender, often branched, and rooted in the soil; leaf petiolate, sori borne within sporocarp, indusiate, heterosporous. Asplenium 13. But opting out of some of these cookies may affect your browsing experience. (With Methods)| Industrial Microbiology, How is Cheese Made Step by Step: Principles, Production and Process, Enzyme Production and Purification: Extraction & Separation Methods | Industrial Microbiology, Fermentation of Olives: Process, Control, Problems, Abnormalities and Developments. 2. Adventitious, branched roots develop in clusters from below the nodes. Abaxial surface of Cycas revoluta microsporophyll, showing microsporangia. Cyathea 11. Sporangium is stalked and annulus is vertical in position. Pteris 18. All the entire sporangium develops from a single initial cell and the development of sporangium is leptosporangiate type. The sporangia, instead of being all alike, are of two distinct kinds. Absence of circinate venation of developing leaf, sporangia aggregate in a special kind of spike; gametophyte subterranean, cylindrical. Aerial shoot is green, slender, somewhat cylindrical to furrow at Upper region with the presence of scaly appendages and sporangia on the uppermost, aerial shoat axis. Leaves that bear sporangia are called sporophylls, while sporangia-bearing stems are called sporangiophores. The continuity of epidermis is broken by sunken stomata present in each groove. 9. Sporangia are borne in the axil of some leaves and there are distinct sterile (vegetative leaves) and fertile (sporophylls) patches on the stem. Can cockroaches be fused together with their Brain Juice? In the species, where cortex is homogeneous, it consists of parenchymatous cells. Share Your PPT File. Leaves pinnate, sporangia develop in spikes and do not develop sori; cap like annulus present. The xylem is C- or U-shaped (Fig. Gnetophyta consists of three genera, Ephedra, Gnetum and Welwitschia. Introduction to Pteridophytes: Pteridophytes constitute a significant and important group in the plant kingdom. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. Strobilus in Pteridophytes | Plant Kingdom | Lecture 12 (iv) This division contains subdivisions Angiosperms & Gymnosperms. Xylem is surrounded by phloem. Polystichum 19. Sporangia are grouped together to form sori. Strobili are characterized by a central axis (anatomically a stem) surrounded by spirally arranged or decussate structures that may be modified leaves or modified stems. 2. Study the strobilus, arrangement of sporangia, L.S. It consists of cuticle, epidermis, spongy parenchyma and the central vascular strand (Fig. It also resembles the internode of aerial sterile shoot except following differences: 1. Below the endodermis is present a single-layered pericycle. Request Permissions. The young embryos develop within the wall of megasporangium and drop out as soon as they develop a root and primary shoot. Sori are marginal to the famine, lies on a vascular commissure between the apex and sinus of a segment. This website uses cookies to improve your experience while you navigate through the website. The outer layers of cortex are sclerenchymatous while the inner layers are parenchymatous. So, it is homosporous. This cookie is set by GDPR Cookie Consent plugin. Strobili bearing microsporangia are called microsporangiate strobili or pollen cones, and those bearing ovules are megasporangiate strobili or seed cones (or ovulate cones). Plants homosporous, leaf magaphyllous, of 1 or 2 types, sporangia in sori, indusiate or ex-indusiate, sporangia development sequential simultaneous. This is specially significant since it introduces in the life cycle a close parallel to the pollination and seed formation habits found in the spermatophytes. Sporangia borne in roundish to elongate linear, abaxial sori, or rarely also on the leaf tissue, indusiate, indusium reniform, sporangia stalked, annulus vertical. Lamina is entire, linear and veins are anastomosing without included free veinlets. Sunken stomata, located only in the furrows, are present. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. What is a trophic hormone? Due to the presence of silica, the stem appears hard and rough to touch. Plant body differentiated into rhizomatous stem, leaf and root; leaf megaphyllous, sporangia aggregates on the leaf margin as sori. (Lycopodium selago L.): It is small, dichotomously branched, erect herb with distinct root system. Therefore, when the megaspore with its newly formed embryonic sporophite falls to the ground, it is for all practical purposes a seed and hence Selaginella approaches the seed habit. 4. The genera Lycopadium is now splitted into Lycopodiwn, Huperzia, Lepidotis & Phlegmarius. Oleandra 20. The rhizome is densely covered with leaves in alternate whorls of three thus giving rise to six rows of leaves. All sporangia develop simultaneously. 3. In my own specimens, in one case, a sporophyll of larger size than usual, with a sporangium The sporophylls are all alike resembling the larger vegetative leaves but the sporangia are of two types (heterosporous) microsporangia and mega-sporangia, so that the sporophylls also are called micro-sporophylls and megasporophylls. Each sporangium is elongated and pendant, and contains a rounded apex (Fig. Also learn about its spore-producing organs. Which part of the male reproductive system store the sperm? It is mostly strobilus forming with the sporangia on the adaxial face of the sporophylls. Pteridophytes: Features, Classification, Reproduction with Examples - Toppr ADVERTISEMENTS: 2. 8. In L.S. Share Your Word File It has about 400 species, which are cosmopolitan in distribution. 246). Sori elongate to long, borne on a vein, covered by a short to very long indusium; sporangia long stalked, annulus interrupted by the stalk, homosporous. Anatomy of Lycopodium (With Diagram) | Pteridophyta - Biology Discussion Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. Meiosis occurs within the sporangia to produce haploid homospores. Can cockroaches be fused together with their Brain Juice? On the strobilus axis the sporophylls are arranged spirally. The Plant Kingdom video Lecture of Biology for NEET AND AIIMS by Dr. Alok Kumar Singh. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. Stem creeping or ascending, sporangia borne singly along the leaf margins, often covered by a flap-like growth of the leaf (indusium). Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. What is a trophic hormone? The dimorphic condition is known as heterospory. Leaves are monomorphic borne at intervals. This cookie is set by GDPR Cookie Consent plugin. Account Disable 12. The stems are densely covered with microphylls and are protostelic. Indusium of sori formed by recurved margin of fertile pinnae, sori few too many nerved. 5. 5. Spores are ellipsoidal to somewhat spheroidal, monolete and surface more or less spinulose. of mature stem shows a number of tissue zones, viz. T.S. In 5. kraussiana stele is distelic. It is photosynthetic in function. Inner to be sclerenchyma is present chloren-chymatous tissue below each ridge. strobilus and spores of lycopodium. Cheilanthes 17. In a few species such as Selaginella and Equisetum, the sporophylls form compact structures called cones or strobili. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. Xylem is surrounded by a zone of phloem and may or may not be further surrounded by the endodermis. Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. The strobilus is formed by the aggregation of sporophylls with sporangia. Cambium develops outside the phloem and produces secondary tissue called prismatic layer. Sporophyll - Wikipedia Spores are tetrahedral, globose, and trilete type. The Hebrew word for conifer cone, itstrubal, is an ancient borrowing from the Greek. Omissions? 234), and is enclosed within a thin or thick spore wall. Plant body devoid of secondary growth, leaves eligulate, definite stobili present, homosporous. 19. Strobilus Definition & Meaning | Dictionary.com Leaves compound, pinnate, sporangiferous spike branched with sporangia in two rows on the terminal branchlets. The air spaces are conspicuously present in the inner cortex zone in between two ridges. Phloem is present in between two strands of metaxylem and made up of phloem parenchyma and sieve tubes. 9. Spores are spheroidal, monolete with prominent wing-like fold on surface (Fig 6.27). The plant body is rootless, branched and possesses hairy rhizome. In L. serratum the stele is actinostele, in which xylem has radiating ribs and the phloem is present in isolated masses alternating with the xylem (Fig. Lycopodium 3. view through strobilus, the sporophylls with sporangia are seen on both sides of the axis. The plant is herbaceous with copiously branching stem, the ultimate divisions usually flabellately dichotomous, trailing, sub-erect or scandent. Due to the presence of silica, the stem appears hard and rough to touch. Strobilus Definition & Meaning - Merriam-Webster Each mature sporangium is 3-lobed, 2 to 3 mm wide and closely clasped with stem axis by a minute forked foliar appendage. Terms of Service 7. The sporangia are mixed, stalked and each possesses a vertical annulus with stomium at one side. Sporangia are grouped together as sori. A T.S. 3. Each sporangiophore is a stalked structure, the free end of which becomes flattened to form a peltate disc (Fig. Margin of the fertile leaf segment is modified as an indusium.
