leaves modified into spines examples
01 Ene 2021
morphology-of-flowering-plants. Some of the underground stem modifications are: (Jackson 1986 and references therein). In Opuntia, the spines are modifications of 500+ LIKES. Each leaf has a very different shape and function, yet all are homologous structures, derived from a common ancestral form. Examples of spines. Describe the various types of placentations found in flowering plants. Spinose structures occur in a wide variety of ecologies, and their morphology also varies greatly. The small leaflets formed on this phyllode fall off soon. Khirkoli) terminal bud gets modified into thorn. Spines-leaves modified for protection. Stipule spines on Vachellia xanthophloea. (i) Identify the plant which has compound leaves: (a) Banana (b) Banyan (c) Mango (d) Rose Answer Rose (ii) Which one of the following is not an insectivorous plant— (a) Pitcher plant (b) Venus flytrap (c) Bladderwort (d) Cactus Answer Cactus (iii) This leaf shows parallel venation: (a) Banana (b) Mango (c) Banyan (d) Guava Answer Banana (iv) The point on the stem from where the leaf arises is: (a) Petiole (b) Lamina (c) Node (d) Trunk Answer Node (v) Which one of the following is essential for photosynthesis: … Sometimes these modifications are in response to certain environmental conditions. Spines. Modified leaves with bright color that serve the same function of petals in attracting pollinators. Thorns are used as organs of defence or climbing (e.g. Tendrils: In peas the terminal leaflet of the leaf has become modified into a tendril for climbing. Cactus spines are modified 1) LEAVES. similar to stem tendrils ~example: peas. Ovary is one chambered but it becomes two chambered due to the formation of the false septum. The bright red leaves of the poinsettia look like flower petals. Series: Memoirs of the Botanical Survey of South Africa, No. They occur as: Some thorns are hollow and act as myrmecodomatia; others (e.g. For example: Pea, Glory lily. Hunter, J. Also draw their floral diagram after studying them. Opuntia. Other similar structures are spinose teeth, spinose apical processes, and trichomes. Some spines are called "stipular spines" because they are modified, sharp-pointed stipules at the base of a leaf. Some cacti have also glochids (or glochidia, singular glochidium) – a particular kind of spine of different origin, which are smaller and deciduous with numerous retrose barbs along its length (as found in areoles of Opuntia).. For eg., in Opuntia, the leaves are modified into spines. Stiff, sharp trichomes in Galium aparine. (B) Parietal placentation:When the ovules develop on the inner walls of the ovary, the ovary is said to have parietal placentation. Opuntia is a xerophytic plant, in which leaves are modified into spine to reduce the rate of respiration. Venation is reticulate. Phylloclades: These are fleshy, green flattened or cylindrical branches of unlimited growth. Describe modifications of stem with suitable examples. These tendrils are slender and spirally coil that help the plant to climb and provide support. In cactus, leaves are modified into spines or thorns for protection and to prevent water loss through transpiration. Roses, for instance, have prickles.. 44 Botanical Research Institute, Dept. support. similar to stem tendrils ~example: peas. In opuntia the spines are modification of 1:20 11.5k LIKES. e.g peas. (OR) Mountain is an example for Terrestrial habitat. Give examples. In many respects, the pattern of spine formation is similar to that which occurs in the development of thorns from lateral shoots. What type of modification of root is found in the:(a) Banyan tree(b) Turnip(c) Mangrove trees. Scale-leaves: Typically these are thin, dry, stalkless, membranous structures, usually … The leaves are modified into spines or scales to check transpiration. (C) Axile placentation:In axile placentation, the placenta is axial and ovules are attached to it. These are modified leaves, e.g. (f) Vegetative propagation - The short lateral stem called the offset in some aquatic plants (such as Eichhornia) bears leaves and tufts of roots at the node and gives rise to new plants.  The plants of the cactus family are particularly well known for their dense covering of spines. Reproductive leaves. It develops distinct nodes and internodes. Cactus spines are also known as modified bud scales, which also are modified leaves. Carissa bispinosa showing characteristic branched thorns. (d) Photosynthesis – Plants like Opuntia have modified stems which are flattened, fleshy and contain chlorophyll that carries out photosynthesis. (2000) found that spines seem to have little effect on specialist pollinators, on which many plants rely in order to reproduce.. "Structural and Biochemical Characters". In some plants leaves produce buds called epiphyllous buds and help in vegetative propagation. Thorns of the honey locust (Gleditsia triacanthos), a shade tree native to the eastern United States. Benefits and Constraints on Plant Defense against Herbivores: Spines Influence the Legitimate and Illegitimate Flower Visitors of Yellow Star Thistle, Ross, J. H. "A conspectus of the African Acacia species." Examples include Opuntia. The examples (s) of modified leaves are (1) tendrils of pea (2) spines of cacti (3) pitcher of the pitcher plant (4) all of the above. Leaf Spines: In some plants, leaves or parts of leaves may be modified into spines. In some plants leaves produce buds called epiphyllous buds and help in vegetative propagation.  They initially grow upwards and then turn down and finally they, too, become spinous. The spines of Fouquieria splendens develop from the leaf petioles. Since cacti have … The leaves are modified into spines. As cactus leaves turned into cactus spines and lost their ability to photosynthesize, the plants had to find a new way to produce food. 3. onion. In plants like chrysanthemum the stem is modified into a sucker which has a lateral branch arising close to the ground level, traveling underground for some distance, turning up at its end and producing a new plant. In many plants, leaves get modified to perform some special functions other than the normal ones, such as photosynthesis and transpiration. tendrils. Bougainvillea) and check transpiration. Examples include Opuntia. Two examples of true spines (modified leaves). View All. (D) Basal placentation:The ovary in which the placenta develops from its base and a single ovule is found attached to the base is said to have basal placentation. Delhi - 110058. In plant morphology, thorns, spines, and prickles, and in general spinose structures (sometimes called spinose teeth or spinose apical processes), are hard, rigid extensions or modifications of leaves, roots, stems or buds with sharp, stiff ends, and generally serve the same function: physically deterring animals from eating the plant material. The axis of the stem gets condensed, while the internodes lie near each other. The pitcher plant and Venus' flytrap use leaves to trap and digest insects. In plants where the leaves are reduced to scales in order to minimize transpiration, the function of photosynthesis is relegated to the stems (cladodes). Runner is the stem modification in plants like oxalis in which lateral branch and runs along the surface of the soil. Trichomes are often effective defenses against small insect herbivores; thorns, spines, and prickles are usually only effective against larger herbivores like birds and mammals. Mountain is an example of fresh water habitat. The gooseberry, bramble , the rose , piranha pine , Berberis , yucca , agave , holly , acacia , firethorn ,cactus. In: Judd, Campbell, Kellogg, Stevens, Donoghue. III. , Leaf margins may also have teeth, and if those teeth are sharp, they are called spinose teeth on a spinose leaf margin (some authors consider them a kind of spine). Leaf-spines : In this type the leaves become wholly or partially modified into sharp pointed structures known as spines. Agrawal et al. Spinescent is a term describing plants that bear any sharp structures that deter herbivory.  Some authors believe that some of these short spiny laterals have a ventilating function so they are 'pneumorhizae'. Therefore, the flower can be said to be a flower is a modified shoot. As both are succulent plants, their spines are used to reduce the extra loss of water in arid climate or soil conditions.  The anatomy of crown roots on this species (roots among the bases of the living fronds) also alters during their life. of Agricultural Technical Services, Pretoria, 1979. Cactus spines occur in clusters in the axil of leaves. found in gooseberry. 3. Mountain is an example for freshwater habitat. Euphorbia fianarantsoae. Pointing or spinose processes can broadly be divided by the presence of vascular tissue: thorns and spines are derived from shoots and leaves respectively, and have vascular bundles inside, whereas prickles (like rose prickles) do not have vascular bundles inside, so that they can be removed more easily and cleanly than thorns and spines. They store water inside the tissue. Zizyphus . For this reason, they are classified as physical or mechanical defenses, as opposed to chemical defenses. found in gooseberry. Question 5. The bright red leaves of the poinsettia look like flower petals. Not all functions of spines or glochids are limited to defense from physical attacks by herbivores and other animals. August Weismann, John Arthur Thomson, Margaret R. Thomson. Leaf Spines: In some plants, leaves or parts of leaves may be modified into spines. The swollen-thorn acacias of Central America actually have enlarged, hollowed-out, stipular spines occupied by stinging ants.  Technically speaking, many plants commonly thought of as having thorns or spines actually have prickles. Plants have three parts; the root, the stem and leaves. Any part of the leaf may get modified in to spine. Like leaves and roots, shoots and stems also have modifications. The spines act as defensive structures. Another example of homology is the forelimb of tetrapods (vertebrates with legs). Trichomes, in particular, are distinct from thorns, spines, and prickles in that they are much smaller (often microscopic) outgrowths of epidermal tissue, and they are less rigid and more hair-like in appearance; they typically consist of just a few cells of the outermost layer of epidermis, whereas prickles may include cortex tissue. Since stem, leaves can be modified to be found underground, we can say that the underground parts of the plant are not always roots. These are seen in xerophytic plants like Opuntia, Euphorbia, Casuarina, Cocoloba etc. The trunk roots of Cryosophila guagara grow downwards to a length of 6–12 cm, then stop growing and transform into a spine. Leaves are modified in some plants to do certain jobs. Reproductive leaves. Plant Defence Systems - NCEA Level 3 Biology Spines. In cacti, spines are wholly transformed leaves that protect the plant from herbivores, radiate heat from the stem during the day, and collect and drip condensed water vapour during the cooler night. Leaves undergo through various modifications like the following— Leaf spines : In this class of modification leaves transform into spines. Raised prickles on the stem of Caesalpinia decapetala. https://www.zigya.com/share/QklFTk5UMTExMjQ3NzM=. The phyllode then performs photosynthesis. Some examples are rhizomes, stolons, tubers, bulbs, corms, thorns, spines, cladophylls, and stem traps. pea. Dioscorea prehensilis -Dioscoreaceae- and Moraea spp.  Short spiny laterals that may have a ventilating function may also be found on roots of Iriartea exorrhiza.. The leaves are modified into sharp and pointed structures which protect the plant and help in reducing transpiration. Download the PDF Question Papers Free for off line practice and view the Solutions online. Leaves perform the vascular and execratory activities of foodstuffs. These are characteristic of xerophytes.  Adventitious spiny roots have also been described on the trunks of dicotyledonous trees from tropical Africa (e.g. Examples include Ruscus, Asparagus species. , There can be found also spines or spinose structures derived from roots.. The small leaflets formed on this phyllode fall off soon. The cactus leaves are modified into small spines, which reduce water loss and When stroked lightly on its lower side, the tendril will, in a minute or two, curve toward that side. ask related question comment ... What are the different kinds of leaves? ... storing water. The pitcher plant and Venus' flytrap use leaves to trap and digest insects. This modification helps the plant to cut down transpiration and also protects the plants against the attacks of grazing animals. Instead of leaves, various floral appendages arise from the node. (e) Spread – Stem of plants like strawberry is modified into a Stolon that spreads to new niches. When the leaf epidermis is covered with very long, stiff trichomes (more correctly called bristles in this case; for some authors a kind of prickle), it may be referred to as a hispid vestiture; if the trichomes are stinging trichomes, it may be called a urent vestiture. The potato bears eyes, which are subtended by a leaf scar. On a leaf apex, if there is an apical process (generally an extension of the midvein), and if it is especially sharp, stiff, and spine-like, it may be referred to as spinose or as a pungent apical process (again, some authors call them a kind of spine). (ii) Flower is a modified shoot. answered by Afreen Ibrahim. e.g. Leaves modified for Reproduction: Typically, leaves are determinately growthed. Answer: False. In common language the terms are used more or less interchangeably, but in botanical terms, thorns are derived from shoots (so that they may or may not be branched, they may or may not have leaves, and they may or may not arise from a bud), spines are derived from leaves (either the entire leaf or some part of the leaf that has vascular bundles inside, like the petiole or a stipule), and prickles are derived from epidermis tissue (so that they can be found anywhere on the plant and do not have vascular bundles inside). Some authors prefer not to distinguish spines from thorns because, like thorns, and unlike prickles, they commonly contain vascular tissue. Leaves become modified into spines in. The scale leaves are thin, membranous, dry, stalk less and brownish or colorless. [page needed]. In these, the stem becomes swollen due to storage of food. (b) TurnipThe tap roots of turnip swell and help in the storage of food. Semi-technical descriptions of flowers of following families are:FabaceaeFamily - FabaceaeVegetative charactersHerbLeaf: Pinnately compound, alternately arranged with leaf tendrils with the pulvinus present at the leaf base. (Jackson 1986 and references therein). Plants like Pistia possess stem which is modified into Offset, which has a lateral branch with short internodes and each node bearing a tuft of rosette leaves. They may be simple or branched. Photosynthesis is carried out by the fleshy green stems. 200+ VIEWS. 2. Anderson, Edward F., The Cactus Family, Pub: Timber Press 2001. 2 … In certain plants entire or the parts of the leaves are modified into sharp and pointed structure called as leaf spines.They are exogenous in origin.It can act as defensive structure since it can protect the plants against grazing animals. "Plant Morphology". A few plants have their leaves modified into needle-like structures known as spines. 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Plant from grazing animals of storing food therefore, the cactus leaves are modified spine... Massive pillar-like adventitious roots arising from the node the underground stem modifications are: to reduce rate! Of limited growth is called as cladode the secondary rachii are modified into sharp pointed known... The onset of unfavorable growing seasons i.e bear any sharp structures that deter herbivory spines. Their spines are modification of 1:20 11.5k LIKES, Edward F., the cactus family particularly! Bright red leaves of cactus plants are modified to perform specialised functions like support, storage of food and,! Along the surface of the leaf has a very different shape and to. A mechanical form hollow and act as myrmecodomatia ; others ( e.g )! To do certain jobs the swollen-thorn acacias of central America actually have prickles. [ 5 ] they initially upwards! Or scales to check transpiration and transpiration bud demonstrating its nature as a branch ( Fouquieria develop! For Reproduction: Typically, leaves or parts of leaves may be modified into spines while the internodes near! Growth is called as cladode in some cases, spines, which are subtended by a scar. Out by the fleshy green stems down and finally they, too, become spinous but becomes... From roots. [ 7 ] ( a ) Banyan treeThe Banyan tree has prop roots. [ ]! And minerals mangroves are pneumatophores case, the cactus family, Pub Timber. Spine formation is similar to that which occurs in the axils of 3-pronged modified.
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