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CAn you please give me the physiological adaptations , anatomical adaptations and morphological adaptations of Xerophytes? {{{Point By Point}}}

Dear student, 

Morphological adaptations in Xerophytes:

1. Stem have a stunted growth
2. Some plants show under ground stem .
3. Certain plants have very hard and woody stem with thick bark.For e.g- acacia, zizyphus etc 
4. The leaves are generally reduced to scaly or spiny Examples include - ruscus, asparagus etc.
5. Very small and narrow leaf blade in many xerophytes. It helps to reduce the transpiration area.
6. But in few plants, the leaves are very thick and leathery that help to reduce transpiration. E.g.calotropis procera
7. Many plants have waxy coating on the upper surface of leaves.
8. The root system is several times larger than the aerial portion.

Anatomical adaptations in xerophytes :

1. Thick cuticle is present on the upper surface of leaves.
2. The epidermal cells of xerophytes are thick walled, and are multiple epidermal layered on both upper and lower surface of leaves. 
3. Stomata are generally reduced in numbers and are of the sunken type. Also, stomata pits are filled with number of hairs.
4. In some plants, thick walled sclerenchyma cells are seen in the hypodermis. E.g. pinus needle
5. Few spongy parenchyma cells with small inter cellular spaces are found. Also, many layered palisade parenchyma is present.
6. The cells are small in size and also the vacuoles are small.
7.In these plants, well developed vascular tissues could be seen.

You can read the answer given by your friend for physiological adaptations.
 

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View Full Answer

  Conifers possess many adaptations that enable them to conserve water.  The following are examples of adaptations that conifer leaves possess which serve to prevent water loss: 

 

Thick cuticle

Sunken stomata

Hypodermis Needle-like leaves

 

    The cuticle is thick and it is composed of a waxy substance that prevents water loss through the epidermis.  Sunken stomata serve to prevent water loss by increasing the relative humidity in the vicinity of each stoma.   The hypodermis is composed of thick-walled cells that are compactly arranged beneath the epidermal layer.  These cells hinder the passage of water into the epidermal layer.  The needle-like leaves reduce the surface area from which water can evaporate.  

    Below is a labeled cross section (100x) of a pine needle (Pinus sp.).  The stated characteristics are demonstrate
d, as well as some additional features. 

 
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Morphological Adaptations of Xerophytes
 
1.     The root system is very well developed with root hairs and root caps. e.g. Calotropis.
2.     The roots are fasciculated as in Asparagus.
 
3.     Stems are stunted, woody, dry, hard, ridged, and covered with thick bark, may be underground, e.g.Saccharum. In Opuntia phylloclade is covered with spines.
 
4.     Stem is covered with thick coating of wax and silica in Equisetum or dense hairs as in Calotropis.
 
5.     Stems may be modified into a thorn e.g. Ulex or cladodes e.g. Asparagus.
 
6.     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.
 
7.     Lamina may be narrow or needle like as in Pinus or divided into many leaflets as in Acacia or succulents as in Aloe.
 
8.     In Euphorbia and Zizyphus jujuba stipules become modified into spines.
 
9.     Xerophytes like Calotropis have hairy covering on the leaves and stems to check transpiration.


Anatomical Adaptations of Xerophytes
1.     Root hairs and root caps are well developed in Opuntia.
 
       2. Roots may become fleshy to store water as in Asparagus
3.    In succulent xerophytes, stems possess a water storage region (thin walled parenchyma cells)
 
4.    Stems of non-succulent xerophytes show a very thick cuticle, well developed epidermis with thickened cell wall, several layered and sclerenchymatous hypodermis e.g. Casuarina.
 
5.    The stems have sunken stomata and well developed vascular and mechanical tissues.
 
6.    Leaves show well developed cuticle, succulent leaves in Aloe, multilayered epidermis in Nerium, sclerenchymatous and several layered hypodermis in Pinus, bulliform cells in Sugarcane.
 
7.    Mesophyll is well differentiated and vascular tissues and mechanical tissues are well developed.
Physiological Adaptations of Xerophytes
 
1.    The stomata of these plants open during night hours and remain closed during the day. This unusual feature is associated with metabolic activities of these plants.
 
2.    In xerophytes, the chemical compounds of cell sap are converted into wall forming compounds (eg) Cellulose, Suberin etc.
3.     Some enzymes, such as catalases, perioxidases are more active in xerophytes than in mesophytes.
 
4.     The capacity of xerophytes to survive in long period of drought is due to the resistance of the hardened protoplasm to heat and desiccation.
 
The Xerophytes have very high osmotic pressure, which increases the turgidity of the cell sap. Morphological Adaptations of Xerophytes
 
1.     The root system is very well developed with root hairs and root caps. e.g. Calotropis.
2.     The roots are fasciculated as in Asparagus.
 
3.     Stems are stunted, woody, dry, hard, ridged, and covered with thick bark, may be underground, e.g.Saccharum. In Opuntia phylloclade is covered with spines.
 
4.     Stem is covered with thick coating of wax and silica in Equisetum or dense hairs as in Calotropis.
 
5.     Stems may be modified into a thorn e.g. Ulex or cladodes e.g. Asparagus.
 
6.     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.
 
7.     Lamina may be narrow or needle like as in Pinus or divided into many leaflets as in Acacia or succulents as in Aloe.
 
8.     In Euphorbia and Zizyphus jujuba stipules become modified into spines.
 
9.     Xerophytes like Calotropis have hairy covering on the leaves and stems to check transpiration.


Anatomical Adaptations of Xerophytes
1.     Root hairs and root caps are well developed in Opuntia.
 
       2. Roots may become fleshy to store water as in Asparagus
3.    In succulent xerophytes, stems possess a water storage region (thin walled parenchyma cells)
 
4.    Stems of non-succulent xerophytes show a very thick cuticle, well developed epidermis with thickened cell wall, several layered and sclerenchymatous hypodermis e.g. Casuarina.
 
5.    The stems have sunken stomata and well developed vascular and mechanical tissues.
 
6.    Leaves show well developed cuticle, succulent leaves in Aloe, multilayered epidermis in Nerium, sclerenchymatous and several layered hypodermis in Pinus, bulliform cells in Sugarcane.
 
7.    Mesophyll is well differentiated and vascular tissues and mechanical tissues are well developed.
Physiological Adaptations of Xerophytes
 
1.    The stomata of these plants open during night hours and remain closed during the day. This unusual feature is associated with metabolic activities of these plants.
 
2.    In xerophytes, the chemical compounds of cell sap are converted into wall forming compounds (eg) Cellulose, Suberin etc.
3.     Some enzymes, such as catalases, perioxidases are more active in xerophytes than in mesophytes.
 
4.     The capacity of xerophytes to survive in long period of drought is due to the resistance of the hardened protoplasm to heat and desiccation.
 
The Xerophytes have very high osmotic pressure, which increases the turgidity of the cell sap.  
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