Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Types of xerophytes
On the basis of their mbrphology, physiology and life cycle pattern, xerophytes are generally classified into the following three categories:
a) Ephemeral annuals also called drought evaders or drought escapers are common in arid zones. These annuals are able to complete their life cycle within a short period of 6-8 weeks during which moisture conditions are favourable. As the moisture gets depleted these annuals dry out leaving behind a crop of seeds to tide over the adverse dry period. They actually avoid the dry period and form seeds which are highly resistant to aridity. Argemone mexicana, Solanurn xanthouupum and Cassia tom are good examples of drought escapers.
b) Succulents: Plants adapted to hot and dry areas are called succulents. They have fleshy stem, leaves and roots which are swollen and serve as water storage organs. These plants are able to accumulate large amounts of water during the brief rainy season. To minimise water loss from the plants leaves either become very small or modify into thorns or are absent altogether to cut down water loss through transpiration. The root system is shallow, with wide horizontally spread stem and leaves are thick, swollen and leathery. Examples of succulents are Opuntia sp., Euphorbia splendens and various types of cacti, and Agave. In many cases stems become succulent as in Opuntia and Eupborbia splendens. They are also called fleshy xerophytes. In such xerophytes, cuticle is thick with a well developed two to three layered hypodermis.
c) Non-succulent perennials: These are actually the true xerophytes or drought resistants, because they possess a number of morphological, anatomical and physiological characteristics which enable them to withstand critical dry conditions. They exhibit rapid root growth and form an extensive root system to tap water from the soil in a most efficient manner. The leaf size is greatly reduced and in many xerophytic grasses, leaves roll on to reduce the leaf surface for restricting loss of water due to transpiration. Some of the examples are Calotropis procera, Acacia nelotica, Saccharurn munja In non-succulent xerophytes, root system is very extensive e.g. Calotropis.
What are the physical properties of Tear Film? Physical Properties of Tear Film: The tear film is a three-layered structure as given below: 1) Outermost Layer: Lipid Layer
Define about the Ultraviolet rays - carcinogenic? Ultraviolet rays: There is ample evidence from epidemiological studies that ultra violet rays derived from the sun induce an i
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
Movement Movement is another characteristic of living things. It does not always mean locomotion or movement from one place to another. In animals movement is quite obvious. W
Alteration of Turgor of Guard Cells There are two ways in which the relative turgor of guard cells may be altered. A decrease in osmotic potential or A decre
am not do erection,am sufferin from epididyme
Q. Show the Embryological Evidence? Embryology is the study of the successive stages of sporogencsis , gametogenesis and the growth and development of the embryo. The number o
Minerals : Bromine Food Source Brominated flour Nutritional Functional role Not known to be essential to humans. Dough improver: KBrO 3 impr
What are some examples of the energetic function of organic molecules? As they are complex molecules, presenting lots of chemical bonds, organic molecules keeps large amount of
Explain Endonucleases Endonucleases are nucleases present in the pancreatic juice like RNAase andDNAase. These hydrolyze internal phosphodiester bonds which are located m
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd