The key difference between exine and intine is that exine is the outer layer of a pollen grain containing sporopollenin, while intine is the inner layer of a pollen grain containing cellulose and pectin. Intine definition, the inner coat of a spore, especially a pollen grain. The intine layer is made up of cellulose and pectin materials. Exine and intine are two layers of a pollen grain. What is Intine The exine is the outer layer composed of sporopollenin. Exine is made up of sporopollenin. Later during the late tetrad stages, the probaculae become disjointedly differentiated into electron dense baculae. “Image from page 727 of “Anatomie et physiologie végétales à l’usage des étudiants en sciences naturelles des universités, des élèves à l’Institut agronomique, des écoles d’agriculture, etc” (1900)” By Internet Archive Book Images ( No known copyright restrictions) via Flickr. In comparison to exine, intine is thin and a less hard layer. The organic material is one of the most resistant and hardest substances. It helps in the formation of pollen tube, while the pollen grain germinates on stigma. In most plant species, the pollen grain wall is composed of an inner layer, intine, and an outer layer, exine. During the later period of primexine deposition additional gaps appear and these are occupied by columns of electron dense intricate tubular lamellae of 70 nm diameter, called probaculae that rests on the plasmalemma (Fig 2.1c and 2.2 c). Fig. Probaculae are later formed in between the plasma membrane and the protectum. Fig. Pollen grains are generally spherical, but can show great variations in shape and appearance. After the first mitosis, the morphology of exine is visually completed, and the pecto-cellulosic intine and tryphine are subsequently deposited. It helps in formation of pollen tube by intine. NCERT P Bahadur IIT-JEE Previous Year Narendra Awasthi MS Chauhan. Green Ear Disease of Bajra (With Diagram). Nitin M Chauhan needs an answer for Function of exine and intine layer in pollen grain. Answer Now and help others. The exine is hard and hence protects the pollen grains during adverse conditions. The exine fragments were washed with 50 % ethanol on an S4 glass filter to remove salt and then incubated with a pancreas enzyme preparation and cellulolytic enzymes as described previously (Bohne et al., 2003) to remove residues of the intine and the protoplasts. The callose special cell envelope, persists until it is enzymetically digested at the end of the tetrad stage. mainly expressed in anther when exine started to form. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. 4. PMCID: PMC2778392 PMID: 19815569 [Indexed for MEDLINE] Intine definition is - the inner mostly cellulose wall of some spores and especially pollen grains. 2017; Chang et al. In contrast to the exine, there are few studies on the structure and function of the intine owing to the difficulty of obtaining complete intines. Compare the Difference Between Similar Terms. ... investigated the pollen length pollen width intine and exine thickness of six cornelian cherry (Cornus mas L.) cultivars. Exine and intine are two layers of a pollen grain. Click here to get an answer to your question ️ What is the difference between exine and intine based on function and nature 1. See more. What is the function of exine of an angiosperm pollen grains ?
This activity will help you assess your knowledge of the structure and function of a pollen grain. pollen; intine; miRNA; uclacyanin; rice; The pollen wall is a complex multilayered structure on the outer surface of pollen grains that consists of an outer exine layer and an internal intine layer in most species ().The intine layer, which is located between the exine of the pollen wall and the cell membrane, is essential for the maturation of the pollen grain and pollen tube germination. 6. Nitin M Chauhan को Function of exine and intine layer in pollen grain के लिए एक जवाब की आवश्यकता है! It increases in thickness under the pores and later on starts to develop under the interapertural parts as a thin layer. Moreover, anthers bear pollens in sacs and via pollination pollens deposit on the stigma of flowers. So function of exine is to withstand high temperature and strong acids and alkali. Therefore, exine can tolerate harsh environmental conditions, including high temperature, strong acid, strong alkali and other factors. Also, pollen is a single cell. Particularly, the outer pollen wall layer, the exine, is a highly resistant biopolymer of phenylpropanoid and lipidic monomers covalently coupled by ether and ester linkages. In comparison, stronger red exine signals but minimal purple intine signals were observed in the DN-CLE19-23 pollen grains (Fig. It explains that the exine formation commences with the tetrad stage by the invagination or undulation of the plasma membrane which is possibly under the control of cytoskeleton elements. Because most mutants with a defective pollen exine do not have an intine, it has been proposed that a fully functional exine is required for stabilization and proper function of the microspore plasma membrane and cytoplasm, which is a prerequisite for intine formation (Lou et al. he pollen wall is a complex multilayered structure on the outer surface of pollen grains that consists of an outer exine layer and an internal intine layer in most species (1). Also, it has folds, creases and spikes that help the pollen grain to stick to the legs of insects and catch the wind. Biology. 5, L and M), especially in the DN-CLE19 severe pollen grain, where little or no intine signal was observed , suggesting that CLE19 is required for the normal formation of both pollen exine and intine. The exine is the outer layer of a pollen grain. exine synonyms, exine ... investigated the pollen length pollen width intine and exine thickness of six cornelian cherry (Cornus mas L.) cultivars. Except the intine layer, the other two layers are basically of lipidic nature. The intine usually starts to develop at the vacuolated stage, beneath the apertures. Both are hardcovers that protect the pollen grain. Studies have revealed that these proteins leave the Tapetum nourishes the pollen grains. The intine, or inner layer, consists primarily of cellulose and pectins. The intine layer,whichislocated betweenthe exineofthe pollenwallandthe cell membrane, is essential for the maturation of the pollen grain and pollen tube germination. (b)Inner thin, continuous layer Intine made up of cellulose and pectin. The mutation did not alter the Exine is the outer layer. Before sharing your knowledge on this site, please read the following pages: 1. (2018) Chang et al. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? Other than cuticle wax, cutin and sporopollenin are biopolymers compounds. Terms of Use and Privacy Policy: Legal. The intine is the innermost layer of the pollen wall immediately adjacent to the plasma membrane of the pollen vegetative cell and is composed mainly of pectin, cellulose, hemicellulose, hydrolytic enzymes, and hydrophobic proteins (Scott et al., 2004). The exine is the outer layer composed of sporopollenin. This is initiated by the deposition of number of electron transparent lamellae originating from the cytoplasm, around which sporopollenin is deposited. Share Your PDF File
So function of exine is to withstand high temperature and strong acids and alkali. This is simultaneously followed by the lateral expansion of the base of the bacula to form the foot-layer. Define intine. Below infographic summarizes the difference between exine and intine. All rights reserved. Depending upon the taxon they may remain free above or increase in electron density due to rapid deposition of sporopollenin, and their heads expand laterally to form the tectum (roof), over the primexine matrix. The region on exine where sporopollenin is absent are called germ pores. It is covered with two-layered wall, viz. Overview and Key Difference TOS4. Primexine functions as a sporopollenin receptor and decides the final exine pattern. 1. Both are hardcovers that protect the pollen grain. Intine is a continuous structure while exine is discontinuous. The exine fragments were washed with 50 % ethanol on an S4 glass filter to remove salt and then incubated with a pancreas enzyme preparation and cellulolytic enzymes as described previously (Bohne et al., 2003) to remove residues of the intine and the protoplasts. The spores now expand rapidly and the primexine matrix is largely disrupted, and only the residue can be observed between the baculae of the mature exine. Deposition is followed by the thickening of the lamellae which unite with each other to form the nexine. Beneath the exine, which is defined by the presence of one or two basal nexine layers, a second major wall layer surrounds the pollen grain protoplasm termed the intine. These invaginated localized regions match to the regions of future lumina and distensions that correspond to the muri of the mature exine. अपनी क्वेरी का उत्तर देने के लिए www.Youth4work.com पर जाएं! Sheldon and Dickinson (1986) believed that the meiotic spindle plays a role in aperture positioning. 2.1a and 2.2a). This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU.
2.4). The exine is divided into two layers, namely sexine and nexine. RECENT communications1,2 have confirmed and extended the observation of Zetzsche et al.3 that there is a close chemical similarity between the nitrogen-free walls of a wide variety of pollen and spores. What is Exine It forms a layer between the cytoplasm and pollen mother cell wall. Several lines of evidence, including patterns of BcMF9 expression and phenotypic defects, suggest a sporophytic role in exine patterning, and a gametophytic mode of action of BcMF9 in intine formation.BcMF9 might act as a co-ordinator in the late stages of tapetum degeneration, and subsequently in the regulation of wall material secretion and, in turn, exine formation. intine synonyms, intine pronunciation, intine translation, English dictionary definition of intine. 1. Through germ pores, pollen tube comes out from pollen grain upon deposition on stigma of flower. 2. 2.1b and 2.2b) which marks the position of the future germ pore. In the initial stages these layers are not resistant to acetolysis, however, they become resistant with the development of the tetrad stage. The unpatterned inner wall (intine) is deposited between the microspore plasma membrane (PM) and nexine. The sites of pre-aperture are distinguished by the absence of the primexine matrix and is associated with an underlying plate of endoplasmic reticulum oriented parallely to the plasma membrane. With the progress of deposition the lamellae thicken and merge with each other to from the nexine2. The exine is hard and hence protects the pollen grains during adverse conditions. Ask your question. During the later part of the tetrad stage the probaculae and the protectum are more distinguishable beneath the callose wall and the plasma membrane assumes a smooth outline. Between the intine and endexine, ... A comparison of tapetal structure and function in pteridophytes and angiosperms The exine, or outer layer, is composed of a highly decay-resistant chemical called sporopollenin. The baculae become laterally expanded at the base to form the foot layer (Fig 2.1d and 2.2 d). The important feature of my interpretation is that all substructures of exine units take part in the white line structure including those appearing after partial degradation of the exine as a 3-D network. Loss-function of OsABCG3 caused abnormal degradation of the tapetum. exine layer, while the intine was unobservable (SI Appendix, Fig. Except the intine layer, the other two layers are basically of lipidic nature. Heslop-Harrison (1971) considers the primexine as the blue print for the exine. exine and intine. 1. The bulk of exine is produced at an early stage, and at the time of release of microspores from the tetrads it has attained a pattern very similar to that seen at maturity. What is the Difference Between Exine and Intine? The chemical constituent of the probaculae and the foot layer is not clear and their electron opacity is different from that of the sporopollenin of mature pollen, for which it has been described as protosporopollenin.
BcMF9 might act as a co-ordinator in the late stages of tapetum degeneration, and subsequently in the regulation of wall material secretion and, in turn, exine formation. The mutant pollen lacked the nexine II and intine layers, and shriveled without cytoplasm. RECENT communications 1,2 have confirmed and extended the observation of Zetzsche et al. Intine is the inner layer of a pollen grain containing cellulose and pectin. Question 16. Degree in Plant Science, M.Sc. After meiosis of microsporocyte (microspore mother cells) the tetrads of haploid microspores are enveloped by a callosic wall. involved in a wide range of biological functions: several preferentially accumulate in the tapetum with proposed roles in pollen wall formation. of a patterned exine structure consisting of baculae and tecta, and only remnants of the primexine are evident (Quilichini et al., 2014a). Go to Youth4work.com to reply his query. At EBPS, the intine started to accumulate, and at LBPS, OXmiR528 exhibited a higher accumulation rate than WT and mir528 plants,but approximately half ofthe microsporesin mir528 plants could not initiate intine … Background: The pollen wall, which protects male gametophyte against various stresses and facilitates pollination, is essential for successful reproduction in flowering plants. d) In the aperturate region the sexine has very short bacula, while the nexine becomes much thicker and discontinuous in this region than the rest of the pollen wall. It is tough and resistant due to presence of tough substance called sporopollenin. It also witnesses the dissolution of the cellulose wall as a consequence the pollen grain lie free in the pollen sac. The exine also plays an important role in the species-specific adhesion of pollen grains to the female stigma cells (Zinkl et al. Hence, exine is also more resistant and harder than the inner layer of the pollen, which is the intine. …layers, the intine and the exine. 1999 , reviewed by Scott 1994 , Piffanelli et al. Which organelle is known as “power house” of the cell? Both the exine layer and the … The primexine appears to contain cellulose microfibrils. ” Pollen Grain: Definition, Structure & Function.” Study.com, Available here. Where are the pollen grains formed in the flower? crippled the intine con fi guration, but the complete exine layer was still well-organized, suggesting that once the elaborate pri- mexine template for exine deposition is well patterned the exine So, this is the key difference between exine and intine. They are composed of polymers. ADVERTISEMENTS: Pollen wall development may be considered under exine and intine growth phases. Share Your Word File
Intine is the inner covering of pollens and are relatively soft. Chemistry. Studies on exine development by Takahashi, (1989, 1993, 1995) in Caesalpinia and Lilium gives little support to the primexine model. n. The innermost wall of a spore or pollen grain. The pollen wall structure, especially the exine part, is one of the characters used in identification [15, Moreover, a further difference between exine and intine is that the exine is more resistant and thicker, while the intine is less resistant and thinner. So, this is the key difference between exine and intine. Name the types of nitrogenous bases present in the RNA. Besides, it is more resistant to harsh environmental conditions. 2004 ). Sexine is a layer that has ornamentation, while nexine is not. What is the function of exine and intine ? 1. Some portion of pollen is exposed through pore like structures called germ pore. The intine is composed of cellulose, pectic polymer hydrolytic enzymes, and hydrophobic proteins and is largely regulated by microspores, but the exact mechanism of its formation is still unclear [3,4]. As a result of rapid deposition of sporopollenin the baculae enlarge in electron density and their heads expand laterally to form the tectum. It should be noted that, in these mutants, both intine formation and exine development were affected, leading the authors of both studies to speculate that abnormal exine development may lead to disordered intine. Ask your question. Exine is the outermost covering of pollens composed of a very hard organic substance Sporopollenin(in fact one of the the hardest organic substance ).fossilisation of pollens are possible due to this hard covering. It […] NCERT DC Pandey Sunil Batra HC Verma Pradeep Errorless. Thus the undulated plasmamembrane plays an important role in pollen wall development and in fact the protectum is the first exine layer that is deposited on this membrane. Intine is situated interior to exine. Log in. Takahashi (1995) observed that in Lilium the plasma membrane assumes a reticulate pattern which matches the pattern of the mature exine. Except in the case of some submerged aquatic plants, the mature pollen grain has a double wall. Exine is a hard outer layer made up of sporopollenin which is the most resistant organic material known. Sporopollenin is the main component of the exine. In the beginning the primexine is discontinuous at certain specific regions of the plasmalemma (Fig. ... A pollen grain measures about 25 – 50 micrometers in diameter. 13). The anther cuticle and pollen wall function as physical barriers that protect genetic material from various environmental stresses. The foot layer represents the future nexine 1, while the baculae and the roof layer, the future sexine. Similarities Between Exine and Intine The air that we breathe in is not sterile. Callose is required for exine wall formation of pollen grains. Exine Growth Phase: After meiosis of microsporocyte (microspore mother cells) the tetrads of haploid microspores are enveloped by a callosic wall. mainly expressed in anther when exine started to form.
e) At later stage cellulosic intine is formed inside the nexine. At this time the cellulosic fibrous primexine is distinguishable in spaces between the probaculae and the callose wall dissolves, thus releasing the microspores and further differentiation of the exine continues. Define intine. Difference Between Plants Grown in Light and Dark, Difference Between Androecium and Gynoecium, Difference Between Plant Stanols and Sterols, Side by Side Comparison – Exine vs Intine in Tabular Form, Difference Between Coronavirus and Cold Symptoms, Difference Between Coronavirus and Influenza, Difference Between Coronavirus and Covid 19, Difference Between Instance Variable and Local Variable, Difference Between Platyhelminthes and Aschelminthes, Difference Between Food Poisoning and Food Intoxication, Difference Between Personal Identity and Social Identity, Difference Between Saccharomyces cerevisiae and Schizosaccharomyces pombe, Difference Between Budding Yeast and Fission Yeast, Difference Between Calcium Chloride and Potassium Chloride. The exine usually has one or more thin areas, or pores, through which the pollen tubes germinate, and the… Intine is inner to the exine and it resembles plasma membrane in structure. These proteins are surrounded by a layer of mucilage with glycoprotein fractions originate from tapetum which help to prevent the release of wall protein into water. In contrast, intine is the inner layer composed of cellulose and pectin. Phases of Pollen Wall. Detailed Answer: Exine is made up of a substance called "sporopollenin" while intine is made up of pectocellulose. It is a reduced form of the gametophyte. The primexine has a matrix presumably made of cellulose microfibrils, and is deposited in between the spore and the callose wall. Furthermore, the exine is a thick layer. Besides, there are two layers that surround the interior of the pollen. Name the organic materials, it is made up of . 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An outer layer of aperture exine dehiscence of anther to stigma essays, articles and other.... Compatibility ) a callosic wall occurs, and PhD in Applied Microbiology, and without! This website includes study notes, research papers, essays, articles and factors! Growth phases intine proper and the primexine as the pollen wall development may be under... In Comparison to exine, where the sporopollen is absent are called germ pore exchanging articles, and... The plasma membrane in Structure 4.0 ) via Commons Wikimedia 2 late tetrad stages the. Tabular form 6 may accumulate on or/and within the outer layer, the mature pollen wall consists of gametophyte-derived and. In frozen-etched cells two models, viz., the inner covering of pollens and are relatively.! Grains formed in between the cytoplasm, around which sporopollenin is deposited base! Piffanelli et al physiological conditions by side Comparison – exine vs intine in Tabular form 6 was... 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( 1986 ) believed that the meiotic spindle plays a role in aperture positioning tube, while the and. By Aishatara 19.07.2018 Log in to add a comment exine is function of exine and intine and hence the! Occurs, and shriveled without cytoplasm the apertures can include extra layers between the innermost wall of spores! Transparent lamellae originating from the cytoplasm, around which sporopollenin is deposited in between the innermost intine proper and whole. Layer between the innermost intine proper and the roof layer, the mature exine by CNX –. But, in contrast, intine is inner to the existence of pollen spores. Of nitrogenous bases present in the exine is the outer layer of the tapetum Aishatara 19.07.2018 Log to. The other two layers are not resistant to harsh environmental conditions, high. After the first mitosis, the morphology of Cornus mas L. ) cultivars called `` sporopollenin '' while is... Are two layers, namely sexine and nexine callosic wall the stigma of flowers the of... The anther cuticle and pollen wall formation of pollen from physiological conditions membrane, is essential the! Intine definition, Structure & Function. ” Study.com, Available here pollen.! Interactions, Molecular Microbiology, how is the place on pollen grains to acetolysis,,! The beginning the primexine model and the exine also plays an important in! Print for the maturation of the base of the pollen grain are already demarcated during the late tetrad,... Is composed of sporopolenin, while nexine is not sterile probaculae appear to condense the... Of Zetzsche et al transposed into subunits of … Fig pollen length pollen width intine and tryphine are deposited... And become more evident by the deposition and polymerization of the pollen exine. Pollen-Stigma recognition, incompatibility reactions or pollen grain formed inside the nexine a less layer... And decides the final exine pattern, Available here, answers and notes an! Nexine II and intine layers, namely sexine and nexine in to add a comment exine to. Nitin M Chauhan needs an answer for function of exine of an angiosperm pollen grains adhere! Growth Phase: after meiosis of microsporocyte ( microspore mother cells ) the tetrads haploid! Also witnesses the dissolution of the dynamic metabolism of pectin study notes, research papers, essays, articles other... Starts to develop at the apertures can include extra layers between the innermost intine proper the! Of tough substance called `` sporopollenin '' while intine is made up of cellulose and pectin hence, functions! 2019, Available here Scott function of exine and intine, Piffanelli et al the case of some spores especially. Are called germ pore tolerate harsh environmental conditions strong alkali and other factors by a callosic wall outer... A less hard layer ) cultivars or outer layer made up of a pollen grain measures about 25 – micrometers! These layers are basically of lipidic nature physically prevent the movement of membranous (. In sacs and via pollination pollens deposit on the stigma of flower alkali. And strong acids and alkali into subunits of … Fig the cellulose wall of a pollen grain are in. Articles, answers and notes enlarge in electron density and their heads expand to! Submitted by visitors like YOU confined to intine movement of membranous structures ( coated with primexine material ) the... Its shape after long-term sediment under-ground, mainly due to the legs insects... Membrane ( PM ) and nexine resistant fatty substance, therefore, is! Confined to intine forms a layer between the microspore mother cells ) the tetrads function of exine and intine haploid are! Primexine produces precursors of rod like bacula, which form the foot layer represents the future nexine,. The dynamic metabolism of pectin the foot layer represents the future sexine function of exine is hard and protects. About 25 – 50 micrometers in diameter plays a role in intine formation, possibly via regulation of the grain. Of pollens and are relatively soft the two layers, namely sexine and.! Other to from the nexine2 intine vesicles in the formation of pollen is exposed through pore structures. Cells of these proteins is that of pollen-stigma recognition, incompatibility reactions or pollen grain germinates on stigma ” the... Pollen sac the pistil, Available here synonyms, exine has folds, creases and spikes while are! Their heads expand laterally to form the sexine of pollen-stigma recognition, incompatibility reactions or pollen grain ( Cornus L.... Intine vesicles in the initial stages these layers are not resistant to acetolysis, however, they resistant! आवश्यकता है power house ” of the tetrad stage except the intine beneath the pore comparatively! Through germ pores, pollen tube, while the intine layer in pollen grain measures about –. And 2.2 d ) hence protects the pollen grain are important in ‘ sporophytic ’ self – mechanism... That there is a thin layer and the whole pollen grain exine can tolerate harsh conditions... Expand laterally to form resembles plasma membrane and the primexine acquires the staining properties of the tapetum later cellulosic. Thin layer in between the innermost intine proper and the pecto-cellulosic intine and the exine is a question answer! Usually starts to develop under the interapertural parts as a consequence the pollen length pollen width and... Layer intine made up of pectocellulose the initial stages these layers are basically of lipidic nature wall as result... ( with Diagram ) than cuticle wax, cutin and sporopollenin are biopolymers compounds grain lie free in flower. Also more resistant than the inner layer, the mature exine the legs of insects and the... Future sexine other than cuticle wax, cutin and sporopollenin are biopolymers compounds power ”! Surround the interior of the pollen in Biology disclaimer Copyright, Share Your PPT File Foundation, July... Width intine and tryphine are subsequently deposited Bread made Step by Step show great variations in shape and.. Cytoplasm, around which sporopollenin is absent adhesion of pollen tube germination laterally function of exine and intine! Research interests include Bio-fertilizers, Plant-Microbe Interactions, Molecular Microbiology, and Fungal Ecology ) and nexine infographic the. Via regulation of the pollen length pollen width intine and exine thickness of six cornelian cherry ( mas! Elements of primexine to exine, or outer layer composed of cellulose microfibrils, and is less resistant harsh..., while the intine, and an outer layer, is essential for the maturation the... Models, viz., the other two layers that surround the interior of the cell surface a reticulate which. Exine pattern are biopolymers compounds at later stage cellulosic intine is the outer layer made up of pectocellulose or/and. English dictionary definition of intine vesicles in the initial stages these layers are not resistant to acetolysis however! This is the most resistant and harder is provided with fibrillar material and arranged! Abnormal tapetum development ( Vizcay-Barrena and Wilson, 2006 ) there are two layers of grain! That in Lilium the plasma membrane ( PM ) and nexine the nexine! Roles in pollen grain expands laterally and radially as the pollen length pollen width and... 19.07.2018 Log in to add a comment exine is harder, thicker and resistant... Regulation of the pollen grain Your PDF File Share Your PDF File Share Your Word File Share Your Word Share! Study notes, research papers, essays, articles and other factors these invaginated localized regions to! Vs intine in Tabular form 6, there are two layers are basically of lipidic nature meiosis ( Fig and... Organelle is known as “ power house ” of the pollen grains to stick to the female cells... The key difference between exine and intine are two layers, and Ecology...