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 is drugs? Intravenous access must be established. Although administration of drugs through a central vein is ideal in a low cardiac output situation, it is rarely possible
Haemodynamics : The type of valves chosen should have excellent haemodynamics. In studies at rest and on exercise the valve should produce only acceptable diastolic gradients in
Concerning the presence of the nucleus what is the difference among animal and bacterial cells? Animal cells (cells of living beings of the kingdom Animalia) have an interior m
STRIPED MUSCLES - These muscles are found in the limbs, body walls, tongue, pharynx and beginning of oesophagus and are under the control of animal's will. These muscle f
Limb Regeneration in Anuran Amphibians We are already aware that the limb of adult frogs does not regenerate later than amputation. Though, some regeneration has been found to
Metabolic Cataysis A large number of chemical reaction occur every moment in a cell to keep it. In the living state, The rate if chemical reaction normally depends upo
Determine about the Psychological tests The construct of attention has been found to comprise several interrelated elements that the paediatric neuropsychologist can consider i
Charles Darwin was the first person to suggest that: a. the present forms of all existing species are the result of natural selection b. species have changed over long periods of t
What are the protective structures of the central nervous system present in vertebrates? In vertebrates the brain and the spinal cord are protected by membranes, the meninges,
CONDUCTIO N OF IMPULSE - IN NON-MYELINATED AXONS - The impulse moves along the axon as local effect by altering the permeability of neighbouring Na + channels and af
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