A., "Hunter" Publisher: Buccaneer Books, 1993, https://books.google.com/books?id=gAv8CAAAQBAJ&pg=PA80, "Cross-Section Through the Prickle of a Rose", https://en.wikipedia.org/w/index.php?title=Thorns,_spines,_and_prickles&oldid=995100554, Articles with unsourced statements from May 2020, Wikipedia articles needing page number citations from April 2019, Wikipedia articles incorporating a citation from Collier's Encyclopedia, Wikipedia articles incorporating citation to the NSRW, Wikipedia articles incorporating citation to the NSRW with an wstitle parameter, Creative Commons Attribution-ShareAlike License, a tiny point at the tip of the leaf (mucronate leaves) (, This page was last edited on 19 December 2020, at 06:20. Answer: False. Produce adventitious plantlets which fall of the leaf and take root in the soil. 4. In plants where the leaves are reduced to scales in order to minimize transpiration, the function of photosynthesis is relegated to the stems (cladodes). Prop roots are massive pillar-like adventitious roots arising from the aerial part of the stem. The phyllode then performs photosynthesis. Modification of the roots means change in the root shape and structure to perform function other than absorption and conduction of water and minerals. For example in Opuntia minute leaves of axillary buds develop into spines. "Structural and Biochemical Characters". 2007. Justify the following statements on the basis of external features:(i) Underground parts of a plant are not always roots. asked in Morphology of Flowering Plants by Lifeeasy Biology. In an extreme case, the cactus, all the leaves are turned into spines and photosynthesis is taken over by the stem. These are characteristic of xerophytes. [5] Adventitious spiny roots have also been described on the trunks of dicotyledonous trees from tropical Africa (e.g. 3. [1] The plants of the cactus family are particularly well known for their dense covering of spines. e.g. All these stem modification perform the function of storing food. Root is modified into spines. The gooseberry, bramble , the rose , piranha pine , Berberis , yucca , agave , holly , acacia , firethorn ,cactus. Phyllode is a petiole modified into a leaf-like structure. Reproductive leaves. Root: Tap root system with root nodules. It develops distinct nodes and internodes. [1], There can be found also spines or spinose structures derived from roots.[5]. similar to stem tendrils ~example: peas. tendrils. A few plants have their leaves modified into needle-like structures known as spines. It also can refer to the state of tending to be or become spiny in some sense or degree, as in: "... the division of the African acacias on the basis of spinescent stipules versus non-spinescent stipules..."[10], There are also spines derived from roots, like the ones on the trunk of the "Root Spine Palms" (Cryosophila spp.). A modified stem capable of limited growth is called as cladode. Tendrils: In peas the terminal leaflet of the leaf has become modified into a tendril for climbing. Plants bearing thorns, spines, or prickles are often used as a defense against burglary, being strategically planted below windows or around the entire perimeter of a property. Placentation refers to the arrangement of ovules inside the ovary. (c) Mangrove treeThe roots modification found in mangroves are pneumatophores. Relationship. These roots grow towards the ground and provide support to the tree. e.g peas. https://www.zigya.com/share/QklFTk5UMTExMjQ3NzM=. (b) Support – Stem of the plants like gravevine and pumpkin are modified into tendrils. Areoles and spines of the tree-like Pereskia grandifolia. Zizyphus 4. (ii) Flower is a modified shoot. Question 5. [16] They also have been used to protect crops and livestock against marauding animals. Delhi - 110058. Roots are modified to perform specialised functions like support, storage of food and respiration. A. Opuntia. These all developed thorns or spines to prevent grazing by herbivores of the leaves and stems and would severely damage the plant. Leaves are changed into spines in xerophytic structures called phylloclade. 200+ SHARES. The natural polysaccharide thickening agent called gum tragacanth is obtained from the sap of this … In these, the stem becomes swollen due to storage of food. Spines. Phylloclades and cladodes are modified branches. (ii) Flower is a modified shoot: The shoot apical meristem changes to floral meristem. [1][2][3], Leaf margins may also have teeth, and if those teeth are sharp, they are called spinose teeth on a spinose leaf margin[1][2] (some authors consider them a kind of spine[2]). Take one flower each of the families Fabaceae and Solanaceae and write its semi-technical description. Leaves are modified into spines in Opuntia (xerophytes) so as to reduce the surface area and minimize rate of water loss by evaporation and transpiration. Leaves are modified into spines. These are seen in xerophytic plants like Opuntia, Euphorbia, Casuarina, Cocoloba etc. Each leaf has a very different shape and function, yet all are homologous structures, derived from a common ancestral form. Stems Leaves Roots None of the above Answer : B Related Video. The cactus leaves are modified into small spines which reduce water loss and can protect the cactus from herbivory. 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 cactus leaves are modified into small spines, which reduce water loss and Therefore, the flower can be said to be a flower is a modified shoot. Also draw their floral diagram after studying them. Some of the underground stem modifications are: Euphorbia. Venation is reticulate. 2021 Zigya Technology Labs Pvt. Basal leaves in onions become fleshy because of the accumulation of food and are found under the ground. Not all functions of spines or glochids are limited to defense from physical attacks by herbivores and other animals. Spinose structures occur in a wide variety of ecologies, and their morphology also varies greatly. 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. Examples include hawthorn hedges in Europe, agaves in the Americas and in other countries where they have been introduced, Osage orange in the prairie states of the US, and Sansevieria in Africa. e.g Dianthus. e.g. Like leaves and roots, shoots and stems also have modifications. In Opuntia, the spines are modifications of 500+ LIKES. 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. Frogs, birds, rabbits and lizards all have different forelimbs, reflecting their different lifestyles. 44 Botanical Research Institute, Dept. Gymnosporia buxifolia thorn, its leaves, nodes, and emergence from an axillary bud demonstrating its nature as a branch. Bracts. (C) Axile placentation:In axile placentation, the placenta is axial and ovules are attached to it. In pea, the leaves are modified into tendrils to help them in climbing around support, in onion leaves are modified to fleshy succulent to store food. The leaves are modified into spines. Reproductive leaves. tendrils. ... storing water. support. As cactus leaves turned into cactus spines and lost their ability to photosynthesize, the plants had to find a new way to produce food. In the many species of the spurge family (Euphorbiaceae), the stipules are modified into paired stipular spines and the blade develops fully. Zigya App. This modification helps the plant to cut down transpiration and also protects the plants against the attacks of grazing animals. Common examples of tendril-producing plants are the grape, members of the squash or melon family (Cucurbitaceae), the sweet pea (Lathyrus odoratus), and the passionflowers (Passiflora species). Here leaves or leaflets get modified to form thin wiry, closely coiled sensitive structure called the tendril that helps the plant to climb the support. They are flattened structures that are photosynthetic and resemble leaf-like branches. [5] Short root spines cover the tuberous base of the epiphytic ant-plant Myrmecodia tuberosa (Rubiaceae), these probably give protection to ants which inhabit chambers within the tuber as they wander over the plant's surface. Sometimes these modifications are in response to certain environmental conditions. (Jackson 1986[5] and references therein). (E) Free central placentation:In free central placentation, the ovules develop on the central axis while the septa are absent. Ovary is one chambered but it becomes two chambered due to the formation of the false septum. Rhizomes (example: ginger, Zingiber) are underground stems that burrow into the ground just below the soil surface, and usually tend to have small, scale-like leaves that are not photosynthetic. Spines. winter. As both are succulent plants, their spines are used to reduce the extra loss of water in arid climate or soil conditions. A modified stem capable of limited growth is called as cladode. The swollen-thorn acacias of Central America actually have enlarged, hollowed-out, stipular spines occupied by stinging ants. Anderson, Edward F., The Cactus Family, Pub: Timber Press 2001. Some climbing plants have leaves modified into tendrils that can curl around surfaces and allow the plant to climb higher to reach more sunlight for photosynthesis. In pea, the leaves are modified into tendrils to help them in climbing around support, in onion leaves are modified to fleshy succulent to store food. Examples of spines. (i) Underground parts of a plant are not always roots: There are certain plants like potato , ginger turmeric in which the stem is modified for the storage of the food and is found underground. Plant Defence Systems - NCEA Level 3 Biology Spines. They are extensions of the cortex and epidermis. 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. Spines are modified leaves, stipules, or parts of leaves, such as extensions of leaf veins. answered by Afreen Ibrahim. (OR) Mountain is an example for Terrestrial habitat. Tendrils are prehensile and sensitive to contact. Two examples of true spines (modified leaves). Series: Memoirs of the Botanical Survey of South Africa, No. Since stem, leaves can be modified to be found underground, we can say that the underground parts of the plant are not always roots. Examples include Opuntia. For eg., in Opuntia, the leaves are modified into spines. silk cotton. Cactus spines are modified 1) LEAVES. of Agricultural Technical Services, Pretoria, 1979. Left: Barberry (Berberis vulgaris) showing lateral buds arising in the axils of 3-pronged, modified leaves called spines. Phylloclades: These are fleshy, green flattened or cylindrical branches of unlimited growth. Bud scales form before the onset of unfavorable growing seasons i.e. III. The bright red leaves of the poinsettia look like flower petals. [5] Lateral roots on these two types of roots, as well as those on the stilt roots on this species, also become spinous. It also reduces transpiration. pea. Leaves are modified in some plants to do certain jobs. (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: … Other similar structures are spinose teeth, spinose apical processes, and trichomes. Opuntia is a xerophytic plant, in which leaves are modified into spine to reduce the rate of respiration. Khirkoli) terminal bud gets modified into thorn. Another example of homology is the forelimb of tetrapods (vertebrates with legs). Frank Vincentz. (c) Protection – Stem of plants like Citrus and Bougainvillea are modified into thorns which protect the plants from the browsing animals. Stem of plants like ginger are modified into rhizome while the stem of colocasia are modified into corm. The spines of Fouquieria splendens develop from the leaf petioles. Leaves undergo through various modifications like the following— Leaf spines : In this class of modification leaves transform into spines. Describe modifications of stem with suitable examples. Roses, for instance, have prickles.[7]. This modification helps the plant to cut down transpiration and also protects the plants against the attacks of grazing animals. Some examples are rhizomes, stolons, tubers, bulbs, corms, thorns, spines, cladophylls, and stem traps. in Crataegus monogyna) bear leaves. 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. 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That function as pneumorhizae on the central axis while the internodes lie near each other of placentations found Flowering. A leaf-like structure apex produces different kinds of floral appendages laterally at successive nodes of the underground modifications! Shoot apical meristem changes to floral meristem out by the stem gets condensed, while the lie! Have modified stems which are subtended by a leaf or parts of a plant are always! Plants are modified into a tendril for climbing wide variety of ecologies, and prickles deterring! The sugars their cells need to function placenta is axial and ovules are attached to it and as!