Xerophyte

As xerophytes ( from Greek: xeros ' dry ' and phytos, plant ') refers to a type of organization of plants that are adapted to extremely dry sites. More specifically it adopted are plants that are adapted to a regular full up shortages of liquid water. This scarcity may be climate-related, such as arid to semi-arid in climates where water is generally lacking or in arctic-alpine zones where water is not available in liquid form, which plants need. The scarcity of water may, however, as in sandy soils (low water-holding capacity ), clay soil ( compacted material, water flows superficially from ) or even with limestone also due to the nature of the soil (often many ruts and cracks, water seeps quickly ). The forms of adaptation to the scarcity of liquid water is called Xeromorphien. Xerophytes limits thus on mesophytes and hygrophytes, the boundaries are not clearly discernible. The halophytes are found morphological adaptations, similar to those of xerophytes, since the presence of NaCl ( table salt), a physiological drought caused (water potential).

Many Xeromorphien based on the reduction of water loss through transpiration. Most of the transpiration happens when you open the stomata. However, this transpiration drives the long-distance transport of water in the plant at ( transpiration ), thus plants are dependent on the opening of the stomata. Xerophytes are adapted to this problem.

One finds xerophytes in many plant families, such as in the sedges ( Cyperaceae ), Crassula family ( Crassulaceae ) or daisy family (Asteraceae).

Classification

Abraham Fahn and David F. Cutler share the xerophytes as follows:

Drought escaping (drought escape )

• Ephemeral ( annuals )

Drought resisting (drought resist )

• Drought evading (drought avoiding ) Geophytes ( to cryptophytes )

• Deep-rooting

• Drought enduring (drought endure ) Succulents (internal water tank) Stem succulents, such as cacti
• Leaf succulents, such as thick leaf plants
• Wurzelsukkulenten

• External water storage

Further adjustments

Other important xeromorphe adjustments are strongly thickened epidermal cells to multilayered epidermis. Often these plants possess a powerful cuticle (eg Clivia nobilis) or in addition to outgrowths of the cuticle. These growths do not represent enlargement of the transpiring surface, since they are dead and filled with air. Result, they often appear as gray or white coating (eg Aechmea fulgens, Peperomia incana ) and reflect some of the light and thus reduce the temperature in the leaf. Since most of the transpiration takes place at the stomata, reduced the creation windless rooms at stomas by sinking (eg oleander leaves ) or formation of wax tubes around this area transpiration. The fume hoods over the stomata can not be so easily removed. In general, a reduction in transpiring surfaces of advantage by eg leaf drop, reduced leaves to thorns or formation of compact forms as in Echinocactus grusonii. Also special metabolic pathways are considered adaptations to dry habitats, such as CAM ( crassulacean acid metabolism ) and C4 syndrome.