Ecological Adaptations of Plants

The transformation of the structure of living things in an environment is called biodiversity. The process in which organisms become better acclimated to their environment is called adaptability. It helps organisms survive in their existing environment. At present, there are around 8.7 million species on earth, living across a diverse range of natural environments.

Ecological adaptations of plants

Based on habitat and the corresponding harmony of plants, organisms are classified as:

• Hydrophytes
• Mesophytes
• Xerophytes
• Epiphytes
• Halophytes

Hydrophytes

Plants that live in water or wetlands are called hydrophytes. Living in ponds, lakes, rivers, and other water bodies, these plants face challenges in the form of low oxygen content, lack of soil and nutrients and less sunlight. 

These aquatic plants are divided into the following five categories, depending on whether they come in contact with water, air and soil. 

• Free-floating hydrophytes: These plants float freely on the water. They are in constant contact with water and air, but not with soil. Examples: Eichhornia and Pistia.
• Rooted floating hydrophytes: The roots of these plants are buried deep in the ground, while their leaves and flowers float on the water. Soil, water, and air all come into contact with these plants. Nelumbo and Nymphaea are two examples.
• Rooted submerged hydrophytes: These plants are completely immersed in water, have roots in the soil and do not interact with air. Examples: Hydrilla and Vallisneria.
• Submerged floating hydrophytes: These plants are completely immersed in water and do not interact with soil and air. Examples: Utricularia and Ceratophyllum.
• Amphibious hydrophytes: These plants are both aquatic and terrestrial. They grow in shallow water. Examples: Typha and Ranunculus.

Adaptations of hydrophytes based on morphology

At the roots

• The roots are not at all in Wolffia and Salvinia or are not well-developed in Hydrilla or well-built in Ranunculus.
• Root canals are replaced by root canals. Example: Eichhornia.

In the trunk

• The stem is long, thin, spongy and curved in a variety of ways.
• In free-floating stems, the stem is thick, short, stoloniferous and spongy; and in floating forms with roots, it is a rhizome.
• Vegetable distribution occurs through runners, stolons, stem and cuts roots, cones, dormant apices and offsets.

On the leaves

• The leaves are thin, long and fibrous in Vallisneria or long and linear at Potamogeton or well-distributed in Ceratophyllum.
• Floating leaves are large and flat like Nymphaea. In Eichhornia and Trapa, petioles swell and become sponges.
• In the form that emerges, the leaves show heterophylly. Example: Ranunculus and Sagittaria.

Mesophytes

Plants that live under moderate conditions are known as mesophytes. These are common ground plants. Example: Hibiscus.

Adaptations based on morphology

• The root system is well-developed with root caps and root hairs
• The stems are usually airy, strong and have many branches.
• Leaves are usually large, broad, thin and have different shapes.

Xerophytes

Plants that live in a dry or xeric state such as deserts are known as xerophytes. Xerophytic space can be of two different types.

• Drought conditions: In these settlements, the soil is slightly dehydrated due to the inability to hold water due to low rainfall.
• Physiological drought conditions: In these habitats, water is plentiful but plants cannot absorb it due to the lack of capillary gaps. Example: Plants in saline and acid soils.

Based on dynamic characters xerophyte is divided into three categories. They are succulents, non-succulent plants and ephemerals.

• Succulents: These are also called drought-tolerant plants. These plants store water in their plant parts during the dry season. These plants produce certain flexible characters to withstand extreme drought conditions. Examples: Aloe and Bryophyllum.
• Non-succulents: These are also called drought-resistant plants. They deal with both external and internal thirst. They have a lot of practice to withstand dry conditions. Examples: Casuarina and Acacia.
• Ephemerals: These are also called drought escapers or drought-resistant. These plants complete their life cycle in a very short time. Example: Mollugo and Argemone.

Adaptations based on morphology

At the roots

• The root system is well-developed and larger than the shooting system.
• Root hair and root caps are also well-developed.

In the trunk

• Stems are strong and woody. They may be in the air or under.
• Stems and leaves are covered with wax or covered with dense hair.
• In some xerophytes, all the internodes in the stem are converted into dense leaves called phylloclades.
• The other two internodes are converted into a green structure called a cladode.
• In some cases, the petiole is transformed into a fleshy leaf as a structure called a phyllode.

On the leaves

• The leaves are usually leathery and shiny to reflect light and heat.
• In some plants such as Euphorbia, stipules are converted to spines.
• All leaves are converted into spines or reduced to scales.

Epiphytes

Epiphytes are plants that grow dependent on other plants. They use only supporting plants as a shelter and not water or food. These epiphytes are often seen in tropical rain forests. Examples: Orchids and Lianas.

Adaptations based on morphology

The root system has been greatly improved. These roots may be of two kinds. They are sticky roots and aerial roots. The adhesive roots fix the epiphytes firmly on the surface of the supporting material.

• Aerial roots are green roots that can hang down and absorb moisture from the atmosphere with the help of velamen sponge tissue.
• The stem of some sweet epiphytes develops a pseudobulb or tuber.
• The leaves are usually small in size and can be fleshy and leathery.
• Myrmecophily occurs most often in epiphytic plants to prevent predators.

Halophytes

There is a special kind of Halophytic plant that grows in salty soils. Examples: Rhizophora.

Halophytes are commonly found along the coast and in Estuaries. The soil is normally moist. Since plants cannot use salt water directly, they need to filter salt using body processes. This plant is also known as mangrove forest and the plants are called mangroves.

Adaptations based on morphology

Lower halophytes are herbaceous but tropical halophytes have more trees.

• In addition to the regular roots, many stilt roots are developed
• A special type of malignant geotropic roots called pneumatophores with pneumathodes for adequate ventilation are also present. They are called respiratory roots.
• The leaves are dense, full, sweet and shiny. Some species are aphyllous.
• Vivipary mode of seed germination is found in halophytes.

Conclusion

Adaptation to nature may be morphological, physiological or behavioural or your combination. Finally, mesophytes, hydrophytes, and xerophytes have developed behavioural, structural, and physiological adaptations as a result of their specific ecological niches. These unique characteristics in the leaves, stems, and roots of these plants have enabled the plant to thrive in its environment. The adaptations help plants to maintain a healthy water balance, allowing them to carry out vital life processes and enhancing their chances of survival in their environments.