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

Importance of forests - fuel wood, Importance of Forests - Fuel Wood T...

Importance of Forests - Fuel Wood The forests are renewable resources which provide us a wide variety of commodities. For man, forests have been a source of recreation and the

How sugar is used in meringues, How sugar is used in Meringues? Egg whi...

How sugar is used in Meringues? Egg whites beaten for a meringue hold air bubbles as the mechanical action of the beaters partly coagulates the egg protein. Sugars make the pro

Explain the requirement of nutrition during stress, Explain the requirement...

Explain the requirement of Nutrition during Stress? We all experience stress at some time or the other in life. Stress is the condition or stimulus that threatens the body's ho

State the similarity between shigella and salmonella, State the similarity ...

State the similarity between Shigella and Salmonella There are many points of similarity between Shigella and Salmonella. They dwell primarily in the gastrointestinal tract, wi

Shifting attention by dopamine, Q. Shifting attention by Dopamine? Dopa...

Q. Shifting attention by Dopamine? Dopamine: Dopamine plays a pivotal role in aspects of shifting attention. Administration of D1/D2 receptor antagonist haloperidol impairs the

What proportion of children with down syndrome, What proportion of children...

What proportion of children with Down syndrome do you expect when women with Down syndrome have children with men who have 46 chromosomes justify your answer?

Genetic terminology, GENETIC TERMINOLOGY (i)         Gene - Mendel us...

GENETIC TERMINOLOGY (i)         Gene - Mendel used the term factor for a gene. A gene is the unit of DNA responsible for the appearance and inheritance of character. (ii)

Which respiratory adaptations or organs do, Q. Which respiratory adaptation...

Q. Which respiratory adaptations or organs do aquatic and terrestrial arthropods respectively present? In crustaceans, typical aquatic beings, there are richly vascularized gil

Inferior epigastric artery-other arterial conduits, Inferior Epigastric Art...

Inferior Epigastric Artery (I.) :  This is a branch of external iliac artery supplying the abdominal wall. It is raised as a free graft for CABG. The usual length availab

What is meant by concentration gradient, What is meant by concentration gra...

What is meant by concentration gradient? Is it correct to refer to "concentration gradient of water"? Concentration gradient is the difference of concentration of a substance

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