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| Adaptation in Plants |
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| Depending upon the quantity of water available in the habitat, plants undergo modification of their body structures so that they can suitably adapt themselves. Accordingly plants are classified into three groups: |
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 Xerophytes |
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 Hydrophytes |
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 Mesophytes |
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| These are plants that grow in places with scanty water such as deserts and sandy hills. The plant is modified so that it can withstand prolonged periods of drought conditions without getting harmed. The following parts of the plant undergo modification. |
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 Root - Produce a long taproot that grows deep into the soil in search of water.E.g. Alhagi |
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 Leaf- Undergo various types of modifications in order to reduce transpiration(loss of water through the leaves), or even store water. |
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| In Acacia and Prosopis the leaves are reduced in size. |
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| In Calotropis the epidermis of the leaf is covered with fine hair. |
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| In Nerium there is multiple epidermis and sunken stomata. |
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| In Opuntia (prickly pear) and Euphorbia the leaves are reduced to spines. |
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 Stem: In Opuntia the stem performs the function of storage of reserve water and so becomes thick and fleshy. It also turns green because of the presence of chlorophyll as it performs photosynthesis. The epidermis of the stem is covered with a waxy layer to prevent loss of water. |
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| These are plants that grow under average conditions of temperature and moisture. This group of plants is intermediate between Xerophytes and Hydrophytes. They show the following adaptations. |
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 Root - The root system is well developed with the taproot in dicotyledons and fibrous roots in monocotyledons. |
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 Stem - The stem is solid and well branched. |
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 Leaves - The leaves are green and well developed. They are provided with cuticle. The leaves have stomata on the lower surface. |
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| Example: |
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| Mango, Maize, Tomato and Wheat |
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| These are plants that grow in water or in very wet places. They may be floating, rooted and floating or submerged. The following are the adaptations found in this group. |
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 Root - The root system is poorly developed as in Eichhornia or absent as in Ceratophyllum |
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 Stem - The stem may be reduced as in Lemna (Duckweed) or may be long, slender, flexible and spongy as in Nelumbo (Lotus). The spongy nature is due to the large air spaces which makes them buoyant. |
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 Leaves - The leaves may be thin and finely dissected as in Hydrilla or ribbon-like as in Vallisneria. In Nelumbo the leaves are large and flat with their upper surface coated with wax. Stomata are found only on the upper surface in floating plants. They are absent in submerged plants. |
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| Xerophytes |
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| Opuntia Agave |
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| Alhagi |
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Hydrophytes |
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| Hydrilla Nelumbo |
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| Eichhornia |
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Mesophytes |
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