Xerophytes (Adaptations to dry environment)
The plants which are growing in xeric (dry) environment (habitat) are called Xerophytes. Deserts are the best examples for xeric environment, where plant face inadequate water and excessive transpiration .xerophytes are classified into the following three categories-Ephemerals [the plants complete their life cycle within a short period. they also called “drought escapers” or “drought evaders”], Succulents [these plants have succulent, fleshy organs, to store to store high amount of water accumulated during rainy seasons. these xerophytes suffer dryness only in external environment],true xerophytes[these plants which are able to live under extreme dry conditions and high temperature].the xerophytes show the following adaptations.
Morphological adaptations
1. Stem shows stunted growth
2. Certain plants have under ground stem to tide over dry season.
3. Plants like acacia, zizyphus etc .have very hard ,woody stem with thick bark.
4. In many plants the leaves are reduced to scaly or spiny e.g.ruscus, asparagus etc.
5. Many plants have very small and narrow leaf blade to reduce the transpiration area.
6. Some plants have shining leaf surface to reflect light. E.g.nerium odorum.
7. In certain plant leaves leaves are very thick and leathery to reduce transpiration. E.g.calotropis procera
8. Many plants have waxy coating on the upper surface of leaves.
9. Folded type leaves are seen in some of the grasses to protect the
10. In non-succulent plants root system is several times larger than the aerial portion.
Anatomical adaptations
1. Presence of thick cuticle on the upper surface of leaves.
2. The epidermal cells are thick walled.
3. Multiple epidermal layers are seen on both upper and lower surface of leaves.
4. Stomata are reduced in numbers and are sunken type.
5. The stomata pits are filled with number of hairs.
6. Thick walled sclerenchyma cells are seen in the hypodermis. E.g. pinus needle
7. Few spongy parenchyma cells with small inter cellular spaces.
8. Presence of many layered palisade parenchyma
9. The cells are relatively smaller in size and vacuoles are small.
10. Well developed vascular tissues are present.
The plants which are growing in xeric (dry) environment (habitat) are called Xerophytes. Deserts are the best examples for xeric environment, where plant face inadequate water and excessive transpiration .xerophytes are classified into the following three categories-Ephemerals [the plants complete their life cycle within a short period. they also called “drought escapers” or “drought evaders”], Succulents [these plants have succulent, fleshy organs, to store to store high amount of water accumulated during rainy seasons. these xerophytes suffer dryness only in external environment],true xerophytes[these plants which are able to live under extreme dry conditions and high temperature].the xerophytes show the following adaptations.
Morphological adaptations
1. Stem shows stunted growth
2. Certain plants have under ground stem to tide over dry season.
3. Plants like acacia, zizyphus etc .have very hard ,woody stem with thick bark.
4. In many plants the leaves are reduced to scaly or spiny e.g.ruscus, asparagus etc.
5. Many plants have very small and narrow leaf blade to reduce the transpiration area.
6. Some plants have shining leaf surface to reflect light. E.g.nerium odorum.
7. In certain plant leaves leaves are very thick and leathery to reduce transpiration. E.g.calotropis procera
8. Many plants have waxy coating on the upper surface of leaves.
9. Folded type leaves are seen in some of the grasses to protect the
10. In non-succulent plants root system is several times larger than the aerial portion.
Anatomical adaptations
1. Presence of thick cuticle on the upper surface of leaves.
2. The epidermal cells are thick walled.
3. Multiple epidermal layers are seen on both upper and lower surface of leaves.
4. Stomata are reduced in numbers and are sunken type.
5. The stomata pits are filled with number of hairs.
6. Thick walled sclerenchyma cells are seen in the hypodermis. E.g. pinus needle
7. Few spongy parenchyma cells with small inter cellular spaces.
8. Presence of many layered palisade parenchyma
9. The cells are relatively smaller in size and vacuoles are small.
10. Well developed vascular tissues are present.
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