Gibberellin A 3 had no significant effect on the bending of the second leaf lamina, nor did any synergism exist between BR and GA 3 in leaf lamina bending or leaf sheath elongation. It is further divided into three parts: i) leaf apex – the tip of the leaf blade, ii) leaf margin – the edge of the leaf and, iii) leaf veins – the small channels or capillaries, which are further subdivided into venules. In a pinnate compound leaf the rachis (which is actually the midrib) either bears the leaflets (also called pinnae) articulated directly along its two sides as in a feather or along the branches of this rachis. Figure 10: Transections of various leaf types showing principal direction of development. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. Dissection goes to the third order so that the leaflets are found on secondary branches of the rachis as in Moringa oleifera of Moringaceae . Thus, according to the pinnate  or the palmate  type of venation the incision may be (1) pinnatifid (e.g., poppy or chrysanthemum leaf); (2) pinnatipartite (e.g., Argemone mexicana); (3) pinnatisect (e.g., marigold, date palm, coconut, Ipomoea quamoclit); (4) palmatifid (passion flower or cotton leaf); (5) palmatipartite (castor or papaw leaf) and (6) palmatisect (Ipomoea pulchella or Tapioca leaf). The blade is the major photosynthetic surface of the plant and appears green and flattened in a plane perpendicular to the stem. These spines may be comparatively small as on the leaves of Argemone mexicana, Pineapple, Agave, Aloe, etc. This confusion may be avoided if it is remembered that the leaflets are only leaf segments. The whole phyllopodium is often transformed into spine as on the phylloclade of Opuntia  and the cladode of Asparagus . (13) Obcordate—reverse of cordate with an apical notch as in Batihinia. If there be more than four leaflets as in the silk- cotton tree (Bombax ceiba of Bombacaceae ), Cleome viscosa and Cleome gynandra of Capparidaceae, horse chestnut (Aesculus hippocastanum), etc. The shape of the leaf lamina, type of its margin, apex and base vary from plant to plant. (7) Hairy—when the surface is covered with hairs. The shape, margin, apex, surface, and extent of incision of lamina varies in different leaves. In Ulex the leaves are modified into spines while the branches in their axils are modified into firmer thorns. A few monocotyledons like some aroids, Smilax, Dioscorea, etc., how­ever, show reticulate venation. Leaves are collectively referred to as foliage, as in "autumn foliage". Among the pinnately incised types some leaves, like those of radish or mustard, show lobes which are irregularly incised. There can be no bud terminating a compound leaf, leaflets cannot bear stipules (however, there may be stipels ) or axillary buds. In angiosperms leaves commonly have a pair of structures known as stipules, which are located on each side of the leaf base and may resemble scales, spines, glands, or leaflike structures. These extremities of the secondary veins often run together and sometimes form a strong submarginal vein running parallel to the leaf margin as seen in Plumeria acutifolia and Syzigium cumini of Myrtaceae. Another such pitcher is found in the epiphytic climber Dischidia rafflesiana (Asclepiadaceae) from Assam. (8) Sagittate—shaped like an arrowhead with the two basal lobes pointing to­wards the base as in Sagittaria sagittifolia and in arum. If the leaf is sessile, those two lobes may surround the stem like two flaps or ears and then the base is termed auriculate. The tendril of Cucurbits may be a prophyll . The Angiosperm leaf shows two principal types of venation. Develop­ment of spinous structures is a feature of the xerophytes. Share Your PPT File. The peculiar case of Lemna   has already been discussed. (3) Succulent—when soft and juicy as in Kalanchoe. In lower plants like the Pteridophytes, the branching of the veins is dichotomous. Leaf Evolution. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. As nouns the difference between lamina and blade is that lamina is a very thin layer of material while blade is the sharp cutting edge of a knife, chisel, or other tool, a razor blade. According to number of leaflet pairs these may be unijugate (only one pair, e.g., Zornia diphylla), bijugate (ground-nut), trijugate, etc. Grass leaves are borne singly at the nodes and, with minor exception, are arranged in two vertical ranks. Some leaves, specially in xerophytes and halophytes, become fleshy because of the storage of water, mucilage and food matter. This is found in Balanites aegyptiaca of Simarubaceae, Hardwickia binnata of Papilionaceae, Campsis grandiflora of Bignoniaceae, etc. Shoeing a number of strong veins (costas) which are. Leaf morphology. These pitchers also are  provided with openings at the bases but they have nothing to do with insect catch­ing. Structurally, this means that the point of leaf…. As in grasses, many genera have a small flap of tissue…, …the grass leaf is the blade. Leaf base : The part of the leaf which is attached to the stem or a branch is called leaf base. (3) Serrate—margin with teeth pointed upwards as in a saw, e.g., china-rose, rose, etc. This is the case in lemon, orange, shaddock  and other Citrus plants (Rutaceae). Welcome to BiologyDiscussion! These spines may be comparatively small as on the leaves of Argemone mexicana, Pineapple, Agave, Aloe, etc. Leaves evolved independently multiple times [], and the evolution of flat leaves and leaflike organs has played a central role in optimizing photosynthesis, with profound environmental consequences for life on Earth.Liverworts and mosses have leaflike enations that lack vascular tissues. In extreme cases of leaf incision (e.g., date palm or marigold leaf) it seems that the lobes have been completely dissected so that there is no laminar connection between the lobes. (6) Tendrillar—when the apex forms a tendril for climbing as in Gloriosa. This indentation is sometimes so prominent that the leaf is said to be incised or lobed. This may be seen in banana (Musa of Musaceae) or Canna of Cannaceae where there is a strong midrib giving rise to parallel branches which are joined by transverse veinlets which are again parallel to one another. Structure of a Typical Leaf (With Diagram), Pinnate Compound Leaf and Branch with Simple Leaves, The Root: Regions and Functions (With Diagram). It is known as pulvinus eg. It bears the weight of the lamina and conducts water and food materials between the stem and leaf. Share Your Word File Using LAMINA to explore leaf traits in the SwAsp collection. (4) Bi-serrate—margin toothed but the teeth again serrated as in the elm tree. In lemons and oranges (Citrus spp ), the prophyll is a spine. Single moisture readings using this moisture meter had mean execution time of ~ 1.0 min. When a tadpole turns into a frog, its tail shrinks and is reabsorbed. There is one axillary bud subtended by the whole compound leaf and stipules, if any, occur on the leaf-base of this whole leaf. (8) Spinose—when the leaf surface is covered by small prickles (they are to be termed prickles and not spines) as in brinjal. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). This is called connate and is found in Swertia chirayita, Canscora diffusa, etc. If the basal lobes fuse together after completely clasping the stem it seems that the stem has perforated the leaf. (7) Cordate or heart-shaped –with a deep notch at the base as in betel vine (Piper betle). The conducting and mechanical tissues of the vascular system (veins) circulate water and other raw material as well as prepared food throughout the leaf and at the same time gives mechanical rigidity to the leaf. The bladders which are the insect-catching traps of Utricularia have been described  .These are modified lobes of leaves. (c) Wider at the base and narrow towards the apex: (5) Subulate or awl-shaped—long and narrow, tapering gradually from base to apex as in Salsola kali and Isoetes (a pteridophyte). Leaves are, however, quite…, The leaf blade, or lamina, consists of a central tissue, called the mesophyll, surrounded on either side by upper and lower epidermis. (ˈlæm ə nə) n., pl. (4) Oblong—more or less rectangular as in banana (Musa sp.). (1) Entire—when the margin is smooth as in mango. Results: The device indirectly estimates leaf moisture content using two electrodes applied to the leaf lamina of fresh and stored samples. (15) Cuneate or wedge-shaped as in Pistia stratiotes. (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) Glaucus—when the surface is covered by a waxy coating causing a shiny bluish or whitish tinge as in the leaves of lotus, arum or Calotropis. The leaf blade: It is also called the lamina. Only a single leaflet is articulated to the top of the winged petiole. Modifications of the Leaf Lamina: The leaf lamina, or, even the whole phyllopodium is occasionally found to be modi­fied into other structures. It’s generally broad and flat. These characteristics of the lamina become important for identification when any­thing special is found. (2) Coriaceous—when it is firm and leathery as in mango. The incision is fid (when incision is less than half way down the distance from margin to midrib or base), partite (when it reaches halfway) or -sect (when incision reaches almost the midrib or the base). lam•i•na. A similar case is the leaf of Nicotiana tabacum which is also sticky and is sometimes described as glutinous. This is the case in many aquatic plants as well. What are the characters Mendel selected for his experiments on pea plant? The pinnae are dissected again into pinnules so that the leaflets (pinnules) are borne not on die rachis but on its branches as in Acacia nilotica , Mimosa pudica, Caesalpinia pulcherrima, etc. As opposed to these compound leaves showing an extreme type of dissection, the ordinary entire or incised (including even the -sect types) leaves are known as simple leaves. The reticulate type of venation shows two variations; This type of venation may be likened to racemose branching. It is in this layer that photosynthesis occurs. The ramifications are called veins and their arrangement is known as vena­tion. Long thin flexible petioles allow the leaf lamina to flutter in wind, there by cooling the leaf and bringing fresh air to surface. If dissection goes on still further even this connection disappears so that the lobes become completely independent of one ano­ther. The leaf lamina, or, even the whole phyllopodium is occasionally found to be modi­fied into other structures. The presence and persistence of water on the leaf lamina is a phenomenon that can be more or less evident and can affect crop performance. (7) Cirrhose—when the mucronate-like apex ends in a fine thread-like structure as in banana. The sheaths are uniformly closed except in the small African genus Coleochloa. Content Guidelines 2. The articulation shows that the leaf is not a simple one but compound. A thin layer of bone, membrane, or other tissue. Which part of the male reproductive system store the sperm? lamina definition: 1. a layer or thin sheet of tissue 2. one of two curved parts at the back of a vertebra (= one of…. These are called lyrate  leaves. (ii) Divergent in fan palm (Borassus flabellifer of Palmaceae). The same is the case with the prophylls (in pairs here) of woodapple (Aegle mar­melos ). The edge of the leaf may be regular or irregular, may be smooth or bearing hair, bristles or spines. Venation is very clear on the lower surface of thin leaves. A closer observation, however, shows that a very narrow lamina connects the lobes. Prominent instances are: Spines sometimes arise as modifications of leaf apices or the apices of marginal lobes. Each leaf typically has a leaf blade called the lamina, which is also the widest part of the leaf.Some leaves are attached to the plant stem by a petiole.Leaves that do not have a petiole and are directly attached to the plant stem are called sessile leaves. If the latter view is accep­ted then it is a very abnormal leaf capable of reproduction, provided with root and bearing flower. LAMINA (Leaf shApe deterMINAtion) is a tool for the automated analysis of images of leaves., Cyperaceae: Characteristic morphological features, Poaceae: Characteristic morphological features. 1. a thin plate or layer. The best answers are voted up and rise to the top. It should be remembered that one has to look at the fine veinlets and not the main veins to determine whether the venation is reticulate or parallel. In this type the vascular supply, after reaching the base of the lamina, breaks up into a number of equally strong veins or costas. The veins, therefore, serve as a circu­latory system as well as like a skeleton of the leaf. Disclaimer Copyright, Share Your Knowledge (3) Scabrous—when the surface is rough because of the presence of short rigid points as in fig leaves. 2. a thin layer or coating lying over another, as in certain minerals. A very thin layer of material.. A thin plate or scale, such as the arch of a vertebra.. Microphyll and megaphyll leaves (i.e., the leaves of lycophyte and euphyllophyte … See more at leaf. This is called perfoliate   and is found in Aloe perfoliata, Pladera perfoliata, Bupleurum, etc. Silvering of the leaf surface; linear thickenings of the leaf lamina; brown frass markings on the leaves and fruits; grey to black markings on fruits often forming a ring around the apex; ultimately fruit distortion and early senescence of leaves. (5) Retroserrate—the teeth are pointed downwards. …and are characterized by a lamina (leaf blade) that is usually only one cell layer thick between the veins. (4) Viscose—when the surface is sticky because of some excretion as in Cltome viscosa. (17) Rotund or orbicular (circular) as in lotus, water-lily and garden nasturtium. Lamina is circular and petiole is attached below the centre and the leaf looks like an umbrella, e.g., lotus, Nelumbo nucifera (Fig. The pattern of leaf incision depends on the type of venation. The leaf apex becomes a tendril in Gloriosa superba. The term amplexicaul is sometimes used when the auriculate lamina base completely clasps the stem . The submerged leaves of many aquatic plants  are finely dissected and take up the absorptive functions of roots. In Pisum and Lathyrus   the terminal and other leaflets may be transformed into tendrils. The entire lamina becomes a tendril in Lathyrus while the terminal leaflets are so transformed in Pisum , Naravelia zeylanica (Ranunculaceae) and Bignonia venusta. Ring in the new year with a Britannica Membership. A compound leaf is sometimes confused with a twig bearing leaves. Is this an example of necrosis or apoptosis? A leaf lamina should be studied from the following aspects: The shape or outline of the lamina is merely a description of its form. The whole compound leaf can never arise from the axil of another leaf which would have been the case if it were a twig. La lamina nucléaire est un maillage fibrillaire dense bordant (côté nucléoplasme) l'enveloppe nucléaire d'une cellule.Il s'agit d'un réseau protéique fibreux, homologue aux filaments intermédiaires qui double la membrane interne de l'enveloppe nucléaire formant une couche de 10 à 20 nm d'épaisseur et interrompue par des pores nucléaires. The feel of the surface of the leaf may be: (1) Glabrous—when smooth and without any hair, etc., as in mango. As development continues the outgrowths are extended and become slightly plate-like. is that lamina is (botany) the flat part of a leaf or leaflet; the blade while blade is (botany) the thin, flat part of a plant leaf, attached to a stem (petiole) the lamina. These again may be of many types: (a) pubescent—when the hair is soft and woolly as in tomato; (b) pilose—when the hairs are long, distinct and scattered as in Grewia flavescens; (c) villose—when hairs are long, soft and closely arranged as in Leucas aspera; (d) tomentose—when hairs are short, dense and cottony as in Terminalia tomentosa, Calolropis procera, etc. The Lamina (Epipodium) of A Leaf (With Diagram) ! [1650–60; < Latin lāmina] In Berberis  and Ulex   the leaves are modified into spines and stages of transition from ordinary leaves to spines are seen, specially, in the seedling stage. This is another rare type found in the Paris plant (Paris quadrifolia ). These are called pedate  leaves. Leaf-blade or Lamina It is the thin, flat part of the leaf that is typically green in color. The air that we breathe in is not sterile. In a simple leaf the lamina, however dissected, will present a single appearance because of the presence of some sort of laminar connection between the dissected lobes. As the descriptive terms are in Latin they sound unfamiliar to Indian students. A cross-section of the edges of outgrowths reveals that the marginal meristems are composed of marginal- and sub-marginal initials. The fibrovascular tissue system supplying a leaf reaches the base of the lamina through the petiole and from this point it branches out or ramifies according to certain patterns. (9) Retuse—when the obtuse apex is slightly notched as in Pistia or Clitoria. (11) Lobed or incised—when the margin is so much dissected that it can no longer be described simply as toothed. Leaflets are borne in pairs as in Tamarindus indica , different species of Cassia, Swietenia mahogoni, etc. (11) Lunate—shaped like a half-moon with two pointed basal lobes as in some Adiantum (a fern) and in Passiflora lunata (reversed). (16) Elliptical—like an ellipse as in Vinca rosea, guava and India-rubber. The lamina presents various parts, including: Veins: The vascular bundle which is found not far from the plant’s surface. Cuneate bases are sharp-pointed, with an angle less than 45 degrees between opposite sides which form a wedge or triangular shape that tapers to a narrow region at the point of attachment of lamina with petiole. Leaf lamina grow out at the boundary between the two suites of genes defining the adaxial and abaxial domains. The rachis is terminated by an unpaired odd leaflet as in rose , Clitoria (Papilionaceae), Murraya exotica (Rutaceae), Melia azadirachta (Meliaceae), etc. Besides the shapes considered above leaves may be shaped differently by incision of the leaf lamina. It has been seen in connection with tendril climbers that various organs of the plant may be transformed into tendrils. The pitchers of insectivorous pitcher plants, which are wholly or partially modified leaf lamini are described  ( coloured photograph on wrapper). These plants are usually rootless. The base of the lamina also is united and continuous with this so that the beginning of the lamina cannot be clearly demarcated. Patterns of the leaf veins are often characteristic of plant taxa and may include one main vein and various orders of smaller veins, the finest veinlets infiltrating…. The compound leaf again may be pinnate  or palmate. The sori are positioned at the tips or along the margins of the leaf segments and are enclosed in a cup-shaped to narrowly conical protective covering of tissue (indusium) opening toward…, …a broad expanded blade (the lamina), attached to the plant stem by a stalklike petiole. They are of different types depending upon the type of edges, the pattern of the veins and the number of blades per leaf. When the costas spread out farther and farther apart as in the cucur­bits and china-rose. (7) Bi-dentate—margin toothed and the teeth are again dentate. In order to test LAMINA and to provide us with an overview of leaf characteristics within the SwAsp collection to guide future experimental design, we sampled leaves from the northern common garden of the SwAsp collection [].As we had previously used ImageJ [] for analysing leaf area, we first performed a comparison analysis … TOS4. Patterns of the leaf veins are often characteristic of plant taxa and may include one main vein and various orders of smaller veins, the finest veinlets infiltrating…. In the date-palm this spine is quite a hard structure. Share Your PDF File 3. the blade or expanded portion of a leaf. The very common Pteridophyte Marsilea quadri-foliata presents a quadrifoliate appearance  although the actual morphology of the four leaflets is not so simple. This is seen in Calotropis procera. Neither ethylene nor (2-chloroethyl)phosphonic acid (ethephon) caused the bending of the second leaf lamina, and neither synergized the BR effect. There are various types of lobing or incision which ate discussed later in connection with leaf incision. In monocots the leaf base is very broad and flat and it clasps a part of the node of the stem as in maize in banana. Leaflets (usually in pairs) are borne directly on rachis. Lobes: The rounded portion of the leaf margin. 26.5). Such leaves contain a special storage tissue. The secondary veins often do not reach the margin but before reaching the edge either fizzle out or curve and run parallel to the margin for a short length. Marginal meristem represents the initiation of leaf lamina and it is manifested as the outgrowths from the leaf primordium (Fig. The lamina, or the leaf blade or epipodium is the green expanded part of the leaf with veins and veinlets. This is known as parallel or striate venation. Usually the lobes towards the apex are larger. In Macfadena unguiscati from Assam, the three terminal leaflets become claw-like hooks . Similarly, some palmately lobed leaves show the lobes arranged like the claw of a bird as in Cayratia pedata. (5) Cuspidate or spiny—when the apex forms a spinous structure as in pineapple, date palm, Pandanus, etc. Before sharing your knowledge on this site, please read the following pages: 1.

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