Xerophytic Adaptations of the Conifers

By Maria Palmieri

 

    Xerophytic adaptations are morphological and physiological characteristics that enable an organism to survive under conditions of water deficit.

    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 demonstrated, as well as some additional features