This process is called transpiration. Instead of having wide flat leaves like most other plants, cacti have evolved to have modified leaves which form sharp spines that protrude from the main plant body. Cacti adapted to extremely xeric conditions with high variations in temperature to harsh for delicate exposed leaves. The spine is technically a modified, sharp-pointed leaf. In cactus spines are found in groups which is called as areole. 11/20/2014 10:46:25 pm. The leaves are modified into the spines which can be observed on the stems. Only 2 types of cactus plants have leaves. ADVERTISEMENT. Thorns also provide protection to the plant from … Leaves release water from the stomata to cool the plant. Many cactus species also use their spines to tap into the moisture in the air. These spines help in storing water in the steams by reducing the amount of transpiration. We can say that spines are modified leaves.6 To be more precise, cactus spines are modified scales grown from an axillary bud (areole). Some spines are called "stipular spines" because they are modified, sharp-pointed stipules at the base of a leaf. Hollies bear spines on the margins of their leaves as a deterrent to would-be browsers. Leaf-spines : In this type the leaves become wholly or partially modified into sharp pointed structures known as spines. Thorns. In adapting to dry habitats, most species of cacti have modified their leaves into spines otherwise too much water would be lost through the pores. The leaves of the cactus are modified into spines because it needs to reduce loss of water through transpiration Reply. A spines attract insects to the plant B spines provide more shade for the plant ... D - spines reduse water loss from the plant. Cactus, flowering plant family comprising 139 genera and nearly 2,000 species, all of which are native to the New World with one possible exception. This is an adaptation of the plant to the arid environment that it is found in. But for the succulent plants to be called Cactus, they need to have a special structure which is present in the Cactus family. Fetch Doc . While most cacti plants are known to be desert plants, they can grow and thrive in a home environment too. Spines are special plant structures. winter. Cactus spines grow from the center and edges of the rounded areoles. The stem has adapted to supply those functions leaving the leaves to adapt to other uses. … The actual “leaves” on the cacti are the spines, which are highly modified to protect it from animals that would love to eat its juicy stems. Other articles where Spine is discussed: angiosperm: Leaf modifications: Spines are also modified leaves. e.g. So cacti have few to no leaves – which is certainly not true of aloe vera. The stem is green and fleshy. The leaves in Cactus are modified into spines, this feature helps to reduce transpiration and also protects the plant from grazing animals. At first, it can be hard to believe that tiny cactus spines offer any real protection from the intense, desert sun. 11/20/2014 10:44:14 pm. Why do floating plants have air space in their root, In cactus leaves are reduced to spines. The bright red leaves of the poinsettia look like flower petals. A cactus (plural cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The pitcher plant and Venus' flytrap use leaves to trap and digest insects. Since it has a bud in its axil, the spine occurs in the relative position of a leaf. The leaves, becoming semi-vestigial, were put to a new use offering shade and surface shelter to the cacti. Any part of the leaf may get modified in to spine. Though cactus spines are modified leaves, they do not contain any of the cells or tissues characteristics of leaves when they mature. 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. Learn more about the members and physical characteristics of the family. Spines-leaves modified for protection. Thus, it can be seen as a structure derived from leaves. The most obvious function of cactus spines is to protect the cacti from animals and people. Stipular Spines Modified for Mutualistic Ants: In bullhorn acacia, evolution has proceeded one more step. answer comment.. 1 Answer. Thank you for A2A. Most cactus morphologists have concluded that cactus spines are either modified leaves or modified bud scales (the difference is inconsequential because bud scales themselves are modified leaves). Cactus is a part of the Succulent family because it has fleshy stems which store water. They can be branched or simple. Spines on cactus: Cactus have spines to protect their succulent stems, and thus their precious water supplies. Spines of cactus plants are modified leaves or shoots located in the axil of a leaf. Cacti are distinguished from the rest of the succulents by the rounded indentations along their stems. Among cacti, spines are very common. In the many species of the spurge family… asked in Morphology of Flowering Plants by Lifeeasy Biology. Over time, cacti modified them into clusters of sharp spines or hairs. Loss of water from the leaves tend the roots to pull more water from the ground. There are, however, a few animals who aren’t deterred by the sharp spines of cacti such as javelina, tortoises and pack rats. It helps in reducing water loss. These new leaves were good at two things: avoiding water loss and protecting the plant (On this topic, I wrote a post on why cacti adapted to have spines instead of leaves). This modification helps the plant to cut down transpiration and also protects the plants against the attacks of grazing animals. Cactus species with few or no spines often produce toxic chemicals as a defense mechanism. The thin, white, radial spines on the outside of the areoles reflect and absorb sunlight. Bud scales form before the onset of unfavorable growing seasons i.e. Cactus spines are actually heavily modified leaves, although they don’t have any of the same structures that are found in normal leaves and are completely inert. Leaves are greatly reduced or entirely absent. "Cactus plants usually consist of spiny stems and roots. The cactus plant grows in a desert where there is a shortage of water. To reduce loss of water through transpiration leaves of cactus plants are modified into spines. Saguaro spines A surprising function of cacti spines is to provide shade for the cactus itself. As a young spine grows from a bud, it quickly turns into a dead lignified fiber.7 Sometimes, the spines are covered by a loose sheath formed from the dried epidermis. The leaves are further modified to provide yellow structures on the margins of the leaves which only function to feed the ants. No, the cactus performs this through stems as the leaves are modified into spines. Numerous plants have spines of course, but in cacti, spines occur in clusters in the axil of leaves, even though the leaves are usually microscopic. The spines are actually modified leaves growing from spots or bumps called areoles. Only in two genera are fully formed leaves present. Reply. Ranya Khurana. Cacti plants have green and thick-walled stems dominated with a lot of needle-like structures referred to as spines. When the spines mature, all the cells in the spines are dead. In this plant the stipular spines are hollow and house mutualistic ants. First, let’s look at the spines of cactus for what they are – the main part of cactus often functions as a modified stem, and its needles are the leaves. Spines are leaves that can no longer photosynthesize or exchange gases. Though thorns and prickles are similar to spines, they’re technically different. Each leaf has a very different shape and function, yet all are homologous structures, derived from a common ancestral form. The cactus leaves are modified into small spines, which reduce water loss and can protect the cactus from plant-eaters. But before you start growing these amazing plants, you need to know the different types of cacti that exist and their unique needs. The areoles occur in rows or spirals along the stem. It is the woody modified leaf or leaf plant. This helps to conserve water and keep away animals. Whenever it rains, the water is collected and stored in the highly modified stem region. In cactus, leaves are modified into spines or thorns for protection and to prevent water loss through transpiration. CONTINUE READING BELOW. First, let’s look at the spines of cactus for what they are – the main part of cactus often functions as a modified stem, and its needles are the leaves. Most of them have reduced leaves that are modified into spines and photosynthetic stems. A cactus makes food in the thin, green outer layer of its stem rather than its leaves. 3. This loss of water by evaporation is called transpiration. It usually forms just below a bud or branch or on leaf. Cactus spines consist of just a core of fibers surrounded by sclereid-like epidermis cells. A spine is a thin, stiff plant structure with a sharp point. Why are the leaves of cactus plants modified into... morphology-of-flowering-plants. JONATHAN. Cactus plants generally have few or no leaves. Zizyphus . ... Read Document. The correct answer is D. Reply. hiipranav hiipranav Answer: Because of the low concentration of water and moisture in that environment. because of the spines transpiration occurs less . Modified branches or stem are known as thorns. The most obvious function of cactus spines is to protect the cacti from animals and people. Plant leaves have tiny pores called stomata that absorb carbon dioxide from the air and release oxygen and evaporated water. They replace the leaves of plants especially the ones which are living in dry conditions. Stipular Spines: Stipules can become modified into spiines for defense. 0 votes . The word "cactus" derives, through Latin, from the Ancient Greek κάκτος, kaktos, a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Rena. A cactus spine is really a kind of modified leaf that becomes rigid and sharp. Note the sharp spines on the cactus above. The central spines discourage foraging animals and capture rainwater, directing it downwards towards the roots. ask related question comment. Most desert leaves have evolved special sizes, shapes, surfaces, colors and other characteristics to keep transpiration at a … Thorns are woody, sharp, straight and pointed structures. The swollen-thorn acacias of Central America actually have enlarged, hollowed-out, stipular spines occupied by stinging ants. Most cacti feature thick photosynthetic stems and leaves that are modified as spines. Spines are formed as modified leaves which take the form of spines as the plant evolves. Bud Scales-are tough, overlapping, waterproof leaves that protect buds from frost, desiccation, and pathogens. Cactus Spines Are Modified Leaves. Soft, broad leaves might be good at photosynthesis, but they lose a lot of water due to evaporation. The main role of these modified stems and leaves is to store water for a reasonably long period and minimize water loss as well. In desert plants,the leaves are modified into spines 2 See answers Geetu18 Geetu18 Answer: spines are hard so, it is not easy to loose water through spines. 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. These are modified buds called “areoles.” From the areoles spring the spines (usually) for which cacti are best known. Cacti have adapted to the harsh conditions they live in by developing areoles instead of branches and spines instead of leaves. therefore, it helps desert plant to save water in there body. It can occur on a stem, leaf or other plant organ. answered by Afreen Ibrahim. The leaves in a cactus plant are modified into spines to prevent the loss of water. 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