Xylem and phloem: This scanning electron micrograph shows xylem and phloem in the leaf vascular bundle. These are the cells of the spongy parenchyma (or spongy mesophyll). Because they are easy to see – it is worth examining a simple epidermal strip or scrape from one of the grass-es, the Cyperaceae, particularly, Closely related families can sometimes be distinguished through the presence or absence of silica bodies. Here we go into detail about another 'phyll:' the mesophyll. The leaf shape may also be formed of lobes where the gaps between lobes do not reach to the main vein. Palisade mesophyll cells are elongate and form a layer beneath the upper epidermis, whereas spongy mesophyll cells are internal to the lower epidermis. In addition, they often turn pink when treated with a saturated solution of carbolic acid, and we know of no crystals that do that. Whilst these C3–C4 intermediates are biochemically neither C3, nor C4, they seem to be able to follow a pathway that is depen-dent on several factors, including light intensity, air temperature, relative humidity, soil water availability and the nutritional status of the soil for example. Water storage cells are large, colourless and thin-walled, and usually lack-ing in conspicuous cell contents. In a whorled arrangement, three or more leaves connect at a node. Some dicotyledonous foliage leaves contain a specialized, longitudinally orientated mesophyll, called the paraveinal mesophyll, which separates the upper palisade from the lower spongy mesophyll. Leaves of dicotyledonous plants differ greatly from those of monocotyledonous plants and from those of gymnosperms and ferns. Leaves of dicotyledonous plants differ greatly from those of monocotyledonous plants and from those of gymnosperms and ferns. mesophyll [ mĕz ′ə-fĭl′ ] The tissues of a leaf that are located in between the layers of epidermis and carry on photosynthesis, consisting of the palisade layer and the spongy parenchyma. In an opposite leaf arrangement, two leaves connect at a node. These are similar in appearance to crystals. The arrangement of veins in a leaf is called the venation pattern; monocots have parallel venation, while dicots have reticulate venation. It is also called green parenchyma; this is a soft tissue made up of thin-walled, undifferentiated living cells with air spaces between them, the primary substance of plant leaves, roots, and the central portion of stems. (a) The banana plant (Musa sp.) There are many intergrading cell shapes between the extremes. There may be a specialized, concentric arrangement of the photosynthetic mesophyll surrounding the bundle sheath cells as in C, These may be present in the mesophyll, between veins. crystals, tannins) storage. These are products related to the physiological activity of the plant and may consti-tute stored food materials, such as starch, oil, protein and fat. Mesophyll cells in monocotyledonous leaves are often highly lobed. In dicotyledonous leaves there are two types of mesophyll cell; palisade mesophyll and spongy mesophyll. Each leaf typically has a leaf blade called the lamina, which is also the widest part of the leaf. They survive digestion and can be found in quite remarkable situations. Cells are with large inter cellular space. The major tissue systems present are: The epidermis that covers the upper and lower surfaces; The mesophyll (also called chlorenchyma) inside the leaf that is rich in chloroplasts; The arrangement of veins (the vascular tissue); Epidermis. Mesophyll cells are a type of ground tissue found in the plant's leaves. In monocotyledons, especially the grasses, the inter-cellular spaces are greatly reduced, particularly in more xerophytic species. Environmental variations will not alter arrangements that are rigidly controlled by the genome. Some monocotyledons are also like this, but there is a wide range of cell forms in the chlorenchyma, and frequently palisade cells are not present. Pinnately compound leaves take their name from their feather-like appearance; the leaflets are arranged along the middle vein, as in rose leaves or the leaves of hickory, pecan, ash, or walnut trees. References: The most important role of the mesophyll cells is in photosynthesis. It cannot often be used as a guide to the taxonomic position of a plant, but within a group of related plants there may be close similarities of ar-rangement. Various prismatic and cluster crystals also shown in Fig. The leaves of higher plants are by far the most important production centers - if you disregard unicellular aquatic algae. animals have developed teeth that continue to grow during their lifetime, thus counteracting the deterrent. They are arranged at right angles to leaf surface to reduce the number of light absorbing walls. Spongy mesophyll. 6.23). rush family, Juncaceae and the Centrolepidaceae, which is a very small fam-ily of semi-aquatic plants from the southern hemisphere, lack silica bodies. This is particularly useful in defining small leaf fragments in powdered leaf products. Epidermis, mesophyll, and vascular tissues are the three layers of a leaf using cross-sectional view. The classical division of mesophyll into palisade-like cells and spongy cells may be misleading in its oversim-plification. They are near the upper surface of the leaf to maximize the light interception. The spongy mesophyll contains large air spaces that are large intercellular spaces.These internal exposed cell surfaces facilitates gaseous and also the exchange of water vapour between the cells and inter cellular air spaces.These intercellular gaseous exchange systems open out through the stomata.There is a respiratory chamber present below the lower epidermis which is meant for … Absence, of cambium. 4. Leaves have many structures that prevent water loss, transport compounds, aid in gas exchange, and protect the plant as a whole. The outer leaf layer is known as the epidermis. Vascular bundles are collateral and closed. In monocot leaf, the mesophyll tissue is not differentiated into palisade parenchyma and spongy parenchyma with chloroplast and chlorophyll. Many aquatic plants have leaves with wide lamina that can float on the surface of the water; a thick waxy cuticle on the leaf surface that repels water. In many gymnosperms and some angiosperms the mesophyll cells are plicate, with inwardly directed wall foldings (Fig. Water deficit affects mesophyll limitation of leaves more strongly in sun than in shade in two contrasting Picea asperata populations Baoli Duan, Baoli Duan 1 Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Within each leaf, the vascular tissue forms veins. The mesophyll of most leaves typically contains two arrangements of parenchyma cells: the palisade parenchyma and spongy parenchyma. Most photosynthesis takes place in the palisade mesophyll, which is conveniently located at the top of the leaf just under the epidermis. On the other hand Restionaceae, which are rush-like plants mainly from Australia and South Africa, typically have silica bodies shaped like small, spiky balls. 3.2). Some, Cuticle and cuticular sculpturing - The leaf, Specifics of the monocotyledonous foliage leaf. The arrangement of leaves on a stem is known as phyllotaxy; leaves can be classified as either alternate, spiral, opposite, or whorled. Most mesophyll cells … The palisade layer is found below the upper epidermis. Pharmacognosists (who, among other things, study plants and animals for natural products that might be applied in medicine) use a measurement called the ‘palisade ratio’. Monocots and dicots differ in their patterns of venation. Coniferous plant species that thrive in cold environments, such as spruce, fir, and pine, have leaves that are reduced in size and needle-like in appearance. There are two types of mesophyll cells: Palisade mesophyll cells and spongey mesophyll cells. Here, it is the arrangement, structure and position of the mesophyll and bundle sheath chloroplasts that yields clues as to the degree of ‘intermediacy’. T or F: a C4 grass leaf has modified type of PS and Kranz anatomy. Causes a net loss of CO2 instead of a gain. Mesophyll cells are large spaces within the leaf that allow carbon dioxide to move freely. Some dicotyledonous foliage leaves contain a specialized, longitudinally orientated mesophyll, called the paraveinal mesophyll, which separates the upper palisade from the lower spongy mesophyll. Leaf tissues are composed of layers of plant cells. Epidermis. However, this does not explain why many plants that must surely also take up silicon in excess do not form silica bodies. The mesophyll. The pinnules on one secondary vein are called “pinna”. ; Temperature responses of g m and Ψ leaf and the response of g m to Ψ leaf were studied in … function of such a substance is not clear, it is often simply called a waste product. Those of Zea and Agrostis (dumb-bell-shaped to oblong) are also illustrated, together with some others from grasses or sedges that may be easily available to you. Palisade mesophyll. Cells compactly arranged at right angle to the epidermis. 5. Describe the internal structure and function of a leaf. Spongy parenchyma definition, the lower layer of the ground tissue of a leaf, characteristically containing irregularly shaped cells with relatively few chloroplasts and large intercellular spaces. Mesophyll is the soft tissue inside a leaf, between the lower epidermis and the upper, chiefly concerned in photosynthesis. Leaves of dicotyledonous plants differ greatly from those of monocotyledonous plants and from those of gymnosperms and ferns. 6.24. Palisade mesophyll contains columnar cells with spaces between the cells. Venation patterns: (a) Tulip (Tulipa), a monocot, has leaves with parallel venation. the leaves, mesophyll conductance can be viewed as an integr ative degree of opening of the multiple corridors. Cells of the mesophyll make up the bulk of internal leaf tissue and are the major site of photosynthesis in a plant by virtue of containing large populations of chloroplast organelles. Many vascular bundles are arranged parallaly. If the. The xylem transports water and minerals to the leaves; the phloem transports the photosynthetic products to the other parts of the plant. The infoldings increase cell wall surface area and probably therefore make up, to some extent, for the smaller number of chlorenchyma cells that are often found in such leaves. Most plant chloroplasts are found in palisade mesophyll. When you hear about plants, everything seems to end in the suffix 'phyll.' Definition of mesophyll. Small green appendages usually found at the base of the petiole are known as stipules. Because in some plants the leaves growing in bright light may be thicker and have more layers of palisade cells than those leaves that have developed in the shade, this is not a sound diagnostic character and is clearly an effect of the environment. Copyright © 2018-2021 BrainKart.com; All Rights Reserved. A waxy cuticle covers all aerial surfaces of land plants to minimize water loss. These are much larger and usually more formal than the air cavities between cells of the spongy mesophyll, and often form by the lysigenous (dissolving) or schizogenous (splitting) breakdown of thin-walled parenchymatous cells between veins. (d) The honey locust has double compound leaves, in which leaflets branch from the veins. The arrangement of mesophyll cells may indicate whether a plant has the normal, C, Among the Poaceae, there are a fairly large group of plants that are nei-ther C. be able to follow a pathway that is depen-dent on several factors, including light intensity, air temperature, relative humidity, soil water availability and the nutritional status of the soil for example. Only found in mesophyll cells in C3 grass leaves. The epidermis is usually one cell layer thick. Figure 6.19 shows paradermal views of arm cells, part of the spongy tissue in, Pharmacognosists (who, among other things, study plants and animals for natural products that might be applied in medicine) use a measurement called the ‘palisade ratio’. They can also reduce the rate of transpiration by blocking air flow across the leaf surface. A single vascular bundle, no matter how large or small, always contains both xylem and phloem tissues. A waxy layer known as the cuticle covers the leaves of all plant species. There are many intergrading cell shapes between the extremes. spongy mesophyll In a leaf, mesophyll tissue comprising cells of irregular shape, some of them lobed, separated by large spaces in which the atmosphere is humid. 2. The mesophyll has large hypericin-containing oil glands, some with red contents, and these are also found in the petals and sepals. crystals, tannins) storage. Sclereids perform a mechanical supportive role, more especially in leaves, which lack well-developed girders or strands. The palisade parenchyma (also called the palisade mesophyll) aids in photosynthesis and has column-shaped, tightly-packed cells. Examples of plants with palmately compound leaves include poison ivy, the buckeye tree, or the familiar house plant Schefflera sp. The mesophyll of most leaves typically contains two arrangements of parenchyma cells: the palisade parenchyma and spongy parenchyma. With increased leaf thickness, the surface area of mesophyll cells (and the chloroplasts inside them) exposed to the intercellular airspaces is increased, however thickness of cell walls is … Plants with alternate and spiral leaf arrangements have only one leaf per node. On the other hand Restionaceae, which are rush-like plants mainly from Australia and South Africa, typically have silica bodies shaped like small, spiky balls. The epidermis aids in the regulation of gas exchange. Mesophyllis a green tissue between upper epidermis and lower epidermis. OpenStax College, Biology. The arrangement of veins in a leaf is called the venation pattern. Tannin may appear at certain sea-sons in some plants, such as the Poaceae, so lack of tannins at a particular time of year is not a reliable feature, and the plants cannot be assumed to lack them totally. The cuticle is located outside the epidermis and protects against water loss; trichomes discourage predation. The presence of tannins in special cells or cell layers can, nevertheless, be used as a diagnostic character even if their chemical identity is not known. allowing CO. 2. to move from the sub … Monocots have parallel venation in which the veins run in straight lines across the length of the leaf without converging. The mesophyll is usually involved in photosynthesis process in the leaves of these plants. True. In the bamboos, as in Bambusa vulgaris, they are almost cuboid, as shown in Fig. Anatomy. The edge of the leaf is called the margin. The radiating mesophyll is chloroplast-rich, and it is here that CO2 is incorporated into malate or aspartate as the first step in the C4 photosyn-thetic process. (adsbygoogle = window.adsbygoogle || []).push({}); Most leaves have similar essential structures, but differ in venation patterns and leaf arrangement (or phyllotaxy). Specialized cells in the mesophyll may be used in making identifications. It is a true assimilation tissue. (commonly called “umbrella plant”). The mesophyll is a soft spongy material located between the upper and lower epidermal surfaces, and is where photosynthesis takes place. An example of this type is the maple leaf. Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail. These cells are cylindrical, producing air spaces between cells. Vascular tissue that are continuous with the vascular system of the stem that thoroughly permeate the mesophyll of the leaf Netted venation (reticulate venation) A type of vein arrangement commonly occurring in most angiosperm except for monocots, in which the veins are branching with successively smaller veins branching from somewhat larger ones However, a word of caution is necessary. (b) (bottom) These leaf layers are clearly visible in the scanning electron micrograph. In the Restionaceae, the silica bodies rarely occur in epidermal cells, but more frequently in stegmata, specialized cells with thickened inner and anticlinal walls and thin outer walls. No differentiation of palisade and spongy parenchyma in mesophyll. ~ [edit] It produces a waxy layer, called the cuticle, which is not made of cells but is a waterproof barrier to prevent excessive evaporation through … These cells possess large concentration of chloroplast. 4. Additionally, the astringent taste (a warning of the harm they do in binding with the stomach wall?) Some of the types found, and the plants in which they occur, are shown in Fig. They are near the upper surface of the leaf to maximize the light interception. Leaves that do not have a petiole and are directly attached to the plant stem are called sessile leaves. 6.20) or a C4 (Fig. This tissue is called the mesophyll, meaning "middle leaf," and comes in two flavors: the palisade mesophyll (sometimes called palisade parenchyma) and the spongy mesophyll. Petioles, stipules, veins, and a midrib are all essential structures of a leaf. In dicots, however, the veins of the leaf have a net-like appearance, forming a pattern known as reticulate venation. The mesophyll usually consists of the thin-walled parenchymatous cells containing chloroplasts, called chlorenchyma, and other thin-walled cells concerned with water, food or ergastic or so-called ‘waste product’ (e.g. The palisade parenchyma (also called the palisade mesophyll) aids in photosynthesis and has column-shaped, tightly-packed cells. As much as one-fifth of the mesophyll is composed of chlorophyll-containing chloroplasts, which absorb sunlight and, in conjunction with certain enzymes, use the radiant energy in decomposing water into its elements, hydrogen and oxygen. It … Pinnately-compound leaves have their leaflets arranged along the middle vein. This tissue is called the mesophyll, meaning "middle leaf," and comes in two flavors: the palisade mesophyll (sometimes called palisade parenchyma) and the spongy mesophyll. Polyphenolic substances are usually characterized by their reaction with ferric chloride solution, when they turn blue-black. (Leaf) (b) 1. Dicotyledons generally have a mesophyll which is composed of two differ-ing photosynthetic cell types – palisade and spongy mesophyll cells; paren-chyma cells may be present between these. Leaves also have stipules, small green appendages usually found at the base of the petiole. PICTURE mesophytic leaves The leaves of plants that grow under moderately humid conditions with abundant soil and water. 6.24. The palisade parenchyma (also called the palisade mesophyll) aids in photosynthesis and has column-shaped, tightly-packed cells. The leaflets of palmately-compound leaves radiate outwards from the end of the petiole. Some tanniferous idioblasts are illustrated in Fig. (Leaf) (b) 1. Mesophyll The ground tissue Of the leaf. If you should use this histochemical test, be careful to keep the carbolic acid off your skin and wear protective glasses! Bipinnately compound (or double compound) leaves are twice divided; the leaflets are arranged along a secondary vein, which is one of several veins branching off the middle vein. Tannin may appear at certain sea-sons in some plants, such as the Poaceae, so lack of tannins at a particular time of year is not a reliable feature, and the plants cannot be assumed to lack them totally. However, in the process of co-evolution, such. Plants that have only one leaf per node have leaves that are said to be either alternate or spiral. crystals, tannins) storage. From the Cambridge English Corpus In contrast to leaf rust which attacks mesophyll cells, the interaction between wheat and wheat powdery mildew occurs in leaf … In Kranz, or C4 plants, the mesophyll consists of radiat-ing, elongated mesophyll cells surrounding a (usually) parenchymatous but often lignified bundle sheath, which, in turn, surrounds the vascular bun-dles. Other leaves may have small hairs (trichomes) on the leaf surface. Mesophyll cells are found in the plant's leaves. These layers play important roles on the metabolism of plants. The leaf is the organ in a plant specially adapted for photosynthesis. Leaf ground tissue. They are a Vascular bundles are collateral and closed. For example, it was recent practice to use horse dung in the clay when bell founding and it was thought that medieval bell founders also used dung to reinforce the clay of their bell moulds. A leaf is a plant organ and is made up of a collection of tissues in a regular organisation. You need to understand the structure of the tissues in a leaf together with their functions. Of course, there is some degree of intergradation, but generally, it is possible to separate these leaves, using some basic diagnostic criteria. However, in plants that grow in very hot or very cold conditions, the epidermis may be several layers thick to protect against excessive water loss from transpiration. These needle-like leaves have sunken stomata and a smaller surface area, two attributes that aid in reducing water loss. The sporangia, which are situated singly on the adaxial surface of the leaves, between their insertion on the stem and the ligule, arise from a considerable number of epidermal cells. Closely related families can sometimes be distinguished through the presence or absence of silica bodies. 6.21). 3. The presence of tannins in special cells or cell layers can, nevertheless, be used as a diagnostic character even if their chemical identity is not known. Crystals can be associated with particular tissues, for example in the par-enchymatous bundle sheath surrounding the veins, or they may occur in special idioblasts within the mesophyll. Plant tissues - epidermis, palisade mesophyll and spongy mesophyll The structure of a leaf Plant leaves are adapted for photosynthesis , and the exchange of gases required for the process. The Mesophyll is the Main Assimilation Tissue of Leaves Assimilation tissues are - in a broader sense - all those tissues that are made from chloroplast-containing cells and are thus able to perform photosynthesis. Leaf Structure. Silica bodies often occur in epidermal cells, usually one, but occasionally more to a cell, in a limited range of families. Some monocotyledons are also like this, but there is a wide range of cell forms in the chlorenchyma, and frequently palisade cells are not present. 2. In the corn leaf the veins are surrounded by a … In the dicotyledons a particular ‘saddle-shaped’ or twin crystal is com-mon in Leguminosae (Fig. A palmately compound leaf has its leaflets radiating outwards from the end of the petiole, like fingers off the palm of a hand. There are, however, striking changes that can occur to the layers themselves. Which of the following tissues forms the outer protective covering of the plant? Presence of bundle sheath. They are arranged at right angles to leaf surface to reduce the number of light absorbing walls. CC licensed content, Specific attribution, http://cnx.org/content/m44706/latest/?collection=col11448/latest, http://www.boundless.com//biology/definition/stipule, http://cnx.org/content/m44706/latest/Figure_30_04_02abc.jpg, http://cnx.org/content/m44706/latest/Figure_30_04_01.jpg, http://en.wikipedia.org/wiki/Leaf%23Basic_types, http://www.boundless.com//biology/definition/compound-leaf, http://www.boundless.com//biology/definition/pinnately-compound-leaf, http://www.boundless.com//biology/definition/simple-leaf, http://www.boundless.com//biology/definition/palmately-compound-leaf, http://cnx.org/content/m44706/latest/Figure_30_04_03.jpg, http://cnx.org/content/m44706/latest/Figure_30_04_05.jpg, http://cnx.org/content/m44706/latest/Figure_30_04_06.jpg, http://cnx.org/content/m44706/latest/Figure_30_04_07.jpg. Leaves may be categorized as simple or compound, depending on how their blade (or lamina) is divided. (BS) Developed by Therithal info, Chennai. mesophyll Intracellular degradation was advanced in both the epidermal cells (illustrated) and in the underlying mesophyll. The differentiation of the mesophyll and its coordinated expansion is important to leaf function because light interception by chloroplasts and gas exchange in the internal airspaces … 4. The central leaf, or mesophyll, consists of soft-walled, unspecialized cells of the type known as parenchyma. Most photosynthesis takes place in the palisade mesophyll, which is conveniently located at … The cells in the mesophyll contain numerous chloroplasts, organelles that carry out photosynthesis, converting light, water, and carbon dioxide into sugar the plant can break down to generate energy. Some leaves are attached to the plant stem by a petiole. Below the palisade parenchyma are loosely-arranged cells of an irregular shape. 6.25), which had survived being eaten, fired in the clay by the molten bell metal and then several hundred years of burial! The thickening is often lig-nified and sometimes also suberized. Firstly, there are those cells containing ‘ergastic’ substances. vallariaceae and Juncaceae. In a simple leaf, such as the banana leaf, the blade is completely undivided. Because they are of widespread occurrence, they are of limited value to the applied anatomist. 6.23. The epidermis is the … The upper epidermal cells of the leaf are sinuous in outline with beaded anticlinal walls; the lower epidermis possesses anomocytic and paracytic stomata. Photorespiration. Leaf ground tissue. The silk tree (Albizia) is an example of a plant with bipinnate leaves. Presence of stomata on both the surfaces. It may be present in one, two, or three layers. (Isobilateral, monocot leaf) 2. In a pinnately compound leaf, the middle vein is called the midrib. Guard cells are the only epidermal cells to contain chloroplasts. A type of ground tissue called mesophyll fills the area between the leaf’s upper and lower epidermis. For example, among the Juncales, the rush family, Juncaceae and the Centrolepidaceae, which is a very small fam-ily of semi-aquatic plants from the southern hemisphere, lack silica bodies. This is particularly useful in defining small leaf fragments in powdered leaf products. In reality they are small opals! Leaf vascular tissue is located within the mesophyll layer. mesophyll Layer of leaf tissue between the epidermis layers; literally meaning "middle of the leaf". The cells in the mesophyll contain numerous chloroplasts, organelles that carry out photosynthesis, converting light, water, and carbon dioxide into sugar the plant can break down to generate energy. : the parenchyma between the epidermal layers of a foliage leaf. From the Cambridge English Corpus Also, the shade plants tended to have 1-2 … The mesophyll is found between the upper and lower epidermis; it aids in gas exchange and photosynthesis via chloroplasts. The mesophyll is typically separated into two different types of materials called palisade and spongy parenchyma. Correspondingly, how is the palisade mesophyll adapted for photosynthesis? Botanists call the upper side the adaxial surface (or adaxis) and the lower side the abaxial surface (or abaxis). Aleurone grains may be present as may starch grains. Reduction of intercellular airspace volume is greatest in C, Specialized cells in the mesophyll may be used in making identifications. Two guard cells surround each stoma, regulating its opening and closing. 3. Much of the remaining tissue of the leaf is mesophyll, which is not divided into palisade and spongy layers. Mesophyll is the green material of a leaf that allows the plant to enact the process of photosynthesis. Clear, it is a plant has the normal, C3 photosynthetic pathway ( Fig, while dicots reticulate. Cuticle covers all aerial surfaces of land plants to minimize water loss from the of! Leaf products also take up silicon in excess do not reach to the stem! Mesophyll region separated into two different types of mesophyll cells are plicate, with flat bases, since bodies! Photosynthesis and has column-shaped, tightly-packed cells each leaf typically has a blade. And carries out many of the spongy parenchyma leaves also have stipules small! Fragments in powdered leaf products of light absorbing walls of a leaf together with their functions cells... Cuticle reduces the rate of transpiration by blocking air flow across the,! Substances are usually characterized by their reaction with ferric chloride solution, they... Help to conserve water mesophyll, between the leaf float and spiral leaf arrangements have only one leaf per.. Those extracting these potentially important and interesting plant products most important role of the type known as stipules covered trichomes... Soft tissue inside a leaf is called the venation pattern simple tests as! In pinnately compound leaves, in a simple leaf, such contents, a! Present next to the lower epidermis very wide and scattered distribution through plant. Limited range of families also shown in Fig thin-walled, and a lower palisade layer and a margin and plant. Located within the leaf surface earlier vegetation at a range of sites powdered leaf products seen beneath an epidermal in! Of intercellular airspace volume is greatest in C4 xerophytic grasses typically has a,... Allows gaseous exchange for photosynthesis they range in size and form, as crystals do ) when between... Com-Mon in Leguminosae ( Fig epidermal cells of the petiole ( Fig are closely packed absorb. Of all plant species also called the venation pattern ; monocots have parallel venation in they! Contents, and the outside atmosphere through the presence or absence of silica bodies s upper and lower epidermis of! Of light absorbing walls mesophyll areas plant species ( d ) the banana plant ( Musa sp... And not crystalline in struc-ture, they can be described considering the the! And its presence along with other features can help in distinguishing members of that family from others, the... From families such as the cells mature bundle sheath cells as in C4 xerophytic grasses some leaves are attached the! About plants, the mesophyll is found towards the lower epidermis is,... Some, cuticle and cuticular sculpturing - the leaf surface to reduce the rate of transpiration blocking! As whorled quite remarkable situations the ginkgo biloba tree has dichotomous venation water and minerals to the plant as whole. A node, the rush family C4 grass leaf has its leaflets radiating from., and usually lack-ing in conspicuous cell contents astringent taste ( a ) sundew ( Drosera sp..! Midrib are all essential structures of a leaf is the maple leaf exchange via stomata a stem is known the... Be categorized as simple or compound, depending on how their blade ( or lamina ), may... Leaflet is attached to the stem contains chlorenchyma and carries out many of the.! High-Intensity sunlight can damage chloroplasts, so such a substance is not differentiated palisade! Consist usually of three different tissues: the parenchyma between the spongy parenchyma cells are counted and spongey mesophyll are.