Practising given Class 12 Biology Chapterwise Important Questions with solutions will help in scoring more marks in your Board Examinations. 1) Epidermis is covered with thick cuticle to reduce the rate of transpiration. Leaves may stay and function for few days to many years, largely determined by the adaptations to climatic conditions. A. Roots may become fleshy to store water as in Asparagus, 3. This layer forms an insulating envelope and checks increasing temperature. Leaves: The leaves are modified in such a way that water loss due to transpiration reduces to minimum. Thick waxy cuticle function. It is mostly covered with hairs, wax, and silica etc. There are two major classification of plants are non-vascular & vascular. Sunken stomata is present. Both upper as well as lower epidermis are multiseriate or multiple. A: ... Enumerate the morphological adaptations of xerophytes. In xerophytes, the chemical compounds of cell sap are converted into wall forming compounds (eg) Cellulose, Suberin etc. Xerophytes have adapted to arid conditions by storing water in leaves or in stems. (Incidentally this is why it is so dark at ground level in woods/forests even on a sunny day: the tree has ensured that as much light as possible has been absorbed in the canopy by the leaves.) 2. E.g.nerium odorum. Root hairs and root caps are well developed in Opuntia. Plants can sense being touched, and they can use several strategies to defend against damage caused by herbivores. Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail, Morphological, Anatomical and Physiological Adaptations of Xerophytes. Asparagus. Following are some of the morphological, anatomical adaptations: Following are some of the morphological characters of xerophytes. Xerophytes like Calotropis have hairy covering on the leaves and stems to check transpiration. e.g. The plants which are growing in xeric (dry) environment (habitat) are called Xerophytes. Some plants have shining leaf surface to. Opuntia and other cacti). Ø Leaves usually absent in xerophytes. Next, we will discuss specific water-related parameters for quantifying plant water status and briefly consider how changes in the parameters may affect plant functions. One of the most interesting of all botanical adaptations … The root system is very well developed with root hairs and root caps. Ø In heterophyllous forms, the submerged leaves are linear or ribbon like or highly dissected, whereas the floating leaves or aerial leaves are usual or circular shaped. This results in upward rolling of leaves and cutting of the stomatal contact with external atmosphere. Xeromorphism is frequently associated with the loss of leaves and their replacement with … Some of them have very few stomata, or stomata that open at night. It is extensive and more elaborate than shoot system. 1. Question 12. (adsbygoogle = window.adsbygoogle || []).push({}); Xerophytes are group of plants that survive in dry regions. The adaptation of leaves is physical adaptation as it involves the plant changing a physical feature in order for it to maintain water balance Xerophyte plants have to conserve water as rain is scarce in their environment meaning if the plant lost to much water it would no longer be able to carry out photosynthesis as water is a raw material needed for this cellular process to occur. 36. This is another adaptation to xeric conditions. Characteristics of Xerophytes. Saccharum. In some desert grasses, the leaves roll due to the presence of motor or bulliform cells in the epidermis. Plants growing in these conditions are termed xerophytes. Vascular tissues are present in large amount. The aerial leaves show … 8.24D). In addition there are other morphological adaptations to reduce the rate of transpiration. The stomata of these plants open during night hours and remain closed during the day. These are endogenous in origin (arises from pericycle). The vertical lines, called branches, represent a lineage, and nodes are where they diverge, representing a speciation event from a common ancestor. They hold soil in a forest and prevent it from being washed away by heavy rains. Conifers possess many adaptations that enable them to conserve water. 4. These cells are sensitive to changes in turgor and thus, contract when conditions are dry. The stems have sunken stomata and well developed vascular and mechanical tissues. Briefly discuss the different kinds of hydrophytes with examples. Morphological Adaptation Palisade Cell Reduce Water Loss Cushion Plant Succulent Leaf These keywords were added by machine and not by the authors. Dense cluster of hairs cover the sunken stomata. A: The xerophytes show following morphological adaptations to grow in water deficit conditions and minimize water loss: ★ They have very well developed root system to absorb water from deep layers of soil. Saccharum. These adaptations conserve water to be used by the plant. Deserts are the best examples for xeric environment, where plant face inadequate water and excessive transpiration .xerophytes are classified into the following three categories-Ephemerals [the plants complete their life cycle within a short period. The diagram represents the circulatory system in mammal. The plant of this group are adapted to live partly in water and partly above substratum and free from water (a) Xerophytes (b) Mesophytes (c) Hydrophytes (d) Halophytes Answer: (b) Mesophytes. 3. Xerophytes are plants which are adapted to a dry, arid habitat such as deserts or sand dunes. In succulent xerophytes, stems possess a water storage region (thin walled parenchyma cells). Enumerate the morphological and anatomical adaptations of xerophytes. Types of Plants: Botanists classify plants into several groups that have similar & distinguishing characteristics. Give in detail the anatomical adaptations shown by xerophytes. Ex: Capparis 6. Annuals’ “goal” is to grow fast (large leaves, maximal photosynthesis, heavy transpiration), flower, set seed, disperse seed, and persist through the dry period as a seed. The roots are fasciculated as in Asparagus. The morphological, physiological, and behavioral adaptations that desert plants have formed over time enable them to survive the harsh conditions common in arid environments [10]. Plants have evolved on the Earth to grow in what we, as humans, see as extreme environments; from tundra to tropical forests and from deserts to swamps and even oceans. Explore all 4 major phyla of the plants here. Leaves are very much reduced, small scale-like, appearing only for a brief period (Caducous) sometimes modified into spines or scales as in Casuarina, Ruscus, Asparagus. Calotropis. 7. Leaves:  The leaves are modified in such a way that water loss due to transpiration reduces to minimum. scaly or spiny e.g.ruscus, asparagus etc. The structural features and fundamental chemical processes of xerophytes are variously adapted to conserve water, also common to store … Leaves show well developed cuticle, succulent leaves in Aloe, multilayered epidermis in Nerium, sclerenchymatous and several layered hypodermis in Pinus, bulliform cells in Sugarcane. Stem is covered with thick coating of wax and silica in, Leaves are very much reduced, small scale-like, appearing only for a brief period (Caducous) sometimes modified into spines or scales as in, Lamina may be narrow or needle like as in, Root hairs and root caps are well developed in, 2. Stem may also be fleshy and growth remains stunted. Teisher et al. ADVERTISEMENTS: Let us make an in-depth study of the categories of xerophytes and its physiological adaptation. reflect light. i) Xerophytes ii) Mesophytes iii)Halophytes iv) Hydrophytes. Structural Adaptations. The types of adaptations are categorized by observable or measurable means, but genetic change is at the basis of all adaptations. Morphological Adaptations of Xerophytes . In some cases, these may even be absent; e.g., Capparis aphylla. e.g. The stomata of these plants open during night hours and remain closed during the day. In xerophytes, the chemical compounds of cell sap are converted into wall forming compounds (eg) Cellulose, Suberin etc. The capacity of xerophytes to survive in long period of drought is due to the resistance of the hardened protoplasm to heat and desiccation. 7. Following are the anatomical features of different organs of some of the xerophytes: Transverse section of Casuarina stem shows the following anatomical characters. 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