Types of xerophytes, Biology

Assignment Help:

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.


Related Discussions:- Types of xerophytes

Define reagent required and methodology for barfoed test, Define reagent re...

Define reagent required and methodology for Barfoed Test? Reagents - Solutions of glucose, fructose, galactose, lactose, maltose, sucrose and starch - Barfoed's reagent

Halophytes are live in moist soils, Halophytes are plants that live in mois...

Halophytes are plants that live in moist soils with high salt concentrations. Despite being surrounded my water, halophytes are often referred to as "salty desert" plants. Explain

Explain nicotinic acid, Nicotinic acid (Niacin) Niacin refers to both n...

Nicotinic acid (Niacin) Niacin refers to both nicotinic acid and its amide derivative. Nicotinic acid occurs as white or almost white crystals or as a crystalline powder of the

Which nitrogen is found in nature, What is the most abundant form under whi...

What is the most abundant form under which nitrogen is found in nature? The most abundant nitrogen-containing molecule found in nature is molecular nitrogen (N2). The air is 80

What is the use of adrenergic receptor, Q. What is the use of Adrenergic Re...

Q. What is the use of Adrenergic Receptor? Adrenergic Receptors are also subdivided into 2 major categories: ALPHA α - or- BETA β In general, when NE (E) binds to alpha r

Active instruments-small occlusal, Active instruments -This category o...

Active instruments -This category of instruments actively engage a restorative , enabling a specific dislodgment force to potentially lift off the prosthesis -These devices

Principles of homeostasis with negative feedback, The principle of homeosta...

The principle of homeostasis is controlling the heating system with a simple thermostat in a house. These components are essentials thermometer, source of heat turning it on or off

What is the reduction of stress on the implant, Reduction of stress on the ...

Reduction of stress on the implant - Removal of prosthesis when it is in the non aesthetic areas - Occlusal adjustment - Reducing Cantilever length - Occlusal splint

Contemporary interests in nutritional biochemistry, Contemporary Interests ...

Contemporary Interests in Nutritional Biochemistry As  newer techniques in biochemistry have emerged from time to time, these were of immense help  in  the  understanding of ut

Causes of degradation of ecosystem due to agriculture, Causes of Degradatio...

Causes of Degradation of Ecosystem Due to Agriculture Degradation of the ecosystem due to agriculture can be on the following accounts: a) Removal of trees (deforestation

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd