3 Groups Compared
The three groups of hydrophytes, mesophytes and xerophytes all have adaptations relative to their environments. These adaptations exist to maintain water balance as water is essential to their survival as it helps plants to carry out life processes.
Root adaptations
Root adaptations across the three groups vary due to their different environments. In hydrophytes, their roots are only used for anchorage so have quite small roots that do not extend far down into the soil. This is because hydrophytes live in aquatic environments so are surrounded by water, therefore the nutrients and other substances they need to carry out life processes such as respiration and photosynthesis surround them and they do not need their roots to collect water. It would be unnecessary for hydrophytes to have well developed and complex root systems.
The roots of mesophytic and xerophytic plants are very different compared to a hydrophytic plant’s roots as unlike a hydrophyte they do rely on their roots to obtain water and various other minerals and gases. Mesophytes have root systems that are either fibrous or taproot which have adapted to collect as much water as possible. These roots also provide anchorage for the plant as mesophytes may live in environments where they are exposed to various weather conditions, such as wind. Since a mesophytes environment is changeable, i.e. there may be periods of drought or extreme heat, their root systems have adapted to this as well.
A xerophytes root is very similar to a mesophytes with its primary function being to obtain water. It’s root systems either run very deep or quite shallow, dependent on the environment of the plant. This adaptation exists so that as much water as possible can be collected as xerophytes tend to reside in environments where water is scarce and in fierce competition for. Therefore by roots either extending far below the ground where water reservoirs may be or near the surface of the soil where the plant can absorb water from sudden rainfall, this allows the xerophyte to absorb all the water available to them.
Stem Adaptations
Across the three plant groups there is a lot of variety in stem adaptations. Xerophytes often have large stems as this is where the majority of their life processes are carried out as well as where any water the plant obtains is stored. Xerophyte stems also have the ability to expand quickly as the environment where they live may be subjective to sudden rainfall so they need to gather as much water as possible, as water is scarce in their environment. The stem of a xerophyte may also be covered in spines or hair which acts as protection from predators as in their environment water is generally scarce.
The stems of mesophytes and xerophytes are quite similar in the sense that they both have turgid cells which provide strength and stability needed to support the plant and also withstand weather conditions. This is because unlike a hydrophyte, xerophytes and mesophytes do not live in aquatic environments where they are surrounded by water.
In contrast, the stems of hydrophytes are very different; they have stems which are thin and flexible as they supported by the water in which they live in. This allows for them to easily move and float in the water. Unlike a xerophyte, their stems do not need to be supported by turgid cells as this would act as a disadvantage as it would limit the flexibility of the hydrophytes stem.
Stomatal Adaptations
In a plant, the stomata is where gases and other minerals and move into the plant as well as where water can move out of the plant via transpiration. Mesophytes have stomata which are found on the lower epidermis of the leaf. This adaptation was made as on the underside of the leaf, the stomata are less exposed to factors which could increase water loss from transpiration.
Xerophytes have stomata which are slightly similar to mesophytes as they are found on the leaf of the plant or if the plant has no leaves, on the stem. These stomata are in sunken pits which help to protect them from their environment as they may be subjective to harsh conditions such as heat and wind which could increase the amount of water lost from transpiration.
Hydrophytes are distinctly different from both mesophytes and xerophytes in terms of the adaptations they have for their stomata. Hydrophytes rarely have stomata as they do not need them in their environment as it is aquatic therefore they are surrounded by water. However in hydrophytes which are partially submerged, their leaves may have stomata on the upper epidermis of their leaves. This allows for efficient gas exchange as well as prevents too much transpiration from happening on hot days.
Waxy Cuticle Adaptations
Some plants have an adaptation of a waxy cuticle which helps to decrease the amount of water lost from evaporation. Mesophytes have leaves which usually have this waxy cuticle where it is thicker on the upper epidermis of the leaf. This is because it is exposed to various conditions such as heat and wind, factors which increase transpiration.
Xerophytes are similar yet different to mesophytes as they also have a waxy cuticle, however it is very thick. This helps to prevent evaporation in their environment which often has very harsh conditions. Thus this reduces the amount of water lost from transpiration as xerophytes need to conserve as much as possible as water is scarce in their environment.
Hydrophytes are very different in terms of their waxy cuticles; hydrophytes which are fully submerged often only have a very thin cuticle or do not have one at all whereas hydrophytes which are partially submerged have a waxy cuticle on the top of their leaf. Hydrophytes which are partially submerged have a cuticle as this prevents damage done by conditions in their environment such as wind or sun as well as prevents algae from growing on the top of the leaf. Hydrophytes which are fully submerged do not need a cuticle as they live in an environment where there is a high amount of water available, therefore unlike xerophytes and mesophytes do not have adaptations such as this which focus around conserving water.
Xylem and Phloem Adaptations
The vascular system across the three plant groups are quite similar, yet also different. Mesophytes have a vascular system which is well developed as it consists of both xylem and phloem vessels which help transport water around the plant from the roots where it is initially absorbed from. This water relies on the xylem and phloem vessels to help it travel around the plant in order to get to the areas it needs to be.
Xerophytes have a vascular system which is similar to a mesophytes as it also has both xylem and phloem vessels. Their vascular system is connected to the roots where water travels upwards to the leaves or if the xerophyte has no leaves, to the stem.
In contrast, a hydrophyte’s vascular system is quite different as it not well developed. This is because a hydrophyte lives in an aquatic environment where water is in abundance, therefore do not need a well developed vascular system like that of a mesophyte or xerophyte’s which transport water throughout the plant. A hydrophyte uses osmosis through its leaves to collect water.
Leaf Adaptations
Physical leaf adaptations vary across all three main plant groups. Leaves of a hydrophyte are dependent on how submerged the plant is. A partially submerged hydrophyte may have leaves which are large and that float on the surface of the water which helps to provide support to the plant. The leaf will also be thick so that it can prevent damage from conditions in which the plant lives in such as water movement or wind. Hydrophytes which are fully submerged will have leaves which are quite thin and also highly dissected. This lets water which contains various minerals and gases needed for survival, to be directly absorbed by the plant as the leaves have a large surface area. These leaves are also quite flexible as conditions where the plant lives may mean its exposed to water movement and/ or wind.
Mesophytic leaves are quite similar to hydrophytic leaves which are partially submerged but different to ones which are fully submerged. The size of these leaves are dependent on the environment the mesophyte is in although are generally thin and flat. Some mesophyte’s leaves may also have hairs which help to create a microclimate, therefore reducing the concentration gradient. The leaves are also green in colour due to the large amount of chloroplasts in them.
Leaves of a xerophyte are quite different compared to a mesophyte and hydrophytes. Xerophytes rarely have leaves and if they do they are rolled up. Instead xerophytes often have spikes. These spikes reduce the amount of water lost through transpiration as there is less surface area, as well as provide protection from predators as xerophytes often live in environments where competition for water is fierce, therefore they need to protect what little water they have.
Root adaptations
Root adaptations across the three groups vary due to their different environments. In hydrophytes, their roots are only used for anchorage so have quite small roots that do not extend far down into the soil. This is because hydrophytes live in aquatic environments so are surrounded by water, therefore the nutrients and other substances they need to carry out life processes such as respiration and photosynthesis surround them and they do not need their roots to collect water. It would be unnecessary for hydrophytes to have well developed and complex root systems.
The roots of mesophytic and xerophytic plants are very different compared to a hydrophytic plant’s roots as unlike a hydrophyte they do rely on their roots to obtain water and various other minerals and gases. Mesophytes have root systems that are either fibrous or taproot which have adapted to collect as much water as possible. These roots also provide anchorage for the plant as mesophytes may live in environments where they are exposed to various weather conditions, such as wind. Since a mesophytes environment is changeable, i.e. there may be periods of drought or extreme heat, their root systems have adapted to this as well.
A xerophytes root is very similar to a mesophytes with its primary function being to obtain water. It’s root systems either run very deep or quite shallow, dependent on the environment of the plant. This adaptation exists so that as much water as possible can be collected as xerophytes tend to reside in environments where water is scarce and in fierce competition for. Therefore by roots either extending far below the ground where water reservoirs may be or near the surface of the soil where the plant can absorb water from sudden rainfall, this allows the xerophyte to absorb all the water available to them.
Stem Adaptations
Across the three plant groups there is a lot of variety in stem adaptations. Xerophytes often have large stems as this is where the majority of their life processes are carried out as well as where any water the plant obtains is stored. Xerophyte stems also have the ability to expand quickly as the environment where they live may be subjective to sudden rainfall so they need to gather as much water as possible, as water is scarce in their environment. The stem of a xerophyte may also be covered in spines or hair which acts as protection from predators as in their environment water is generally scarce.
The stems of mesophytes and xerophytes are quite similar in the sense that they both have turgid cells which provide strength and stability needed to support the plant and also withstand weather conditions. This is because unlike a hydrophyte, xerophytes and mesophytes do not live in aquatic environments where they are surrounded by water.
In contrast, the stems of hydrophytes are very different; they have stems which are thin and flexible as they supported by the water in which they live in. This allows for them to easily move and float in the water. Unlike a xerophyte, their stems do not need to be supported by turgid cells as this would act as a disadvantage as it would limit the flexibility of the hydrophytes stem.
Stomatal Adaptations
In a plant, the stomata is where gases and other minerals and move into the plant as well as where water can move out of the plant via transpiration. Mesophytes have stomata which are found on the lower epidermis of the leaf. This adaptation was made as on the underside of the leaf, the stomata are less exposed to factors which could increase water loss from transpiration.
Xerophytes have stomata which are slightly similar to mesophytes as they are found on the leaf of the plant or if the plant has no leaves, on the stem. These stomata are in sunken pits which help to protect them from their environment as they may be subjective to harsh conditions such as heat and wind which could increase the amount of water lost from transpiration.
Hydrophytes are distinctly different from both mesophytes and xerophytes in terms of the adaptations they have for their stomata. Hydrophytes rarely have stomata as they do not need them in their environment as it is aquatic therefore they are surrounded by water. However in hydrophytes which are partially submerged, their leaves may have stomata on the upper epidermis of their leaves. This allows for efficient gas exchange as well as prevents too much transpiration from happening on hot days.
Waxy Cuticle Adaptations
Some plants have an adaptation of a waxy cuticle which helps to decrease the amount of water lost from evaporation. Mesophytes have leaves which usually have this waxy cuticle where it is thicker on the upper epidermis of the leaf. This is because it is exposed to various conditions such as heat and wind, factors which increase transpiration.
Xerophytes are similar yet different to mesophytes as they also have a waxy cuticle, however it is very thick. This helps to prevent evaporation in their environment which often has very harsh conditions. Thus this reduces the amount of water lost from transpiration as xerophytes need to conserve as much as possible as water is scarce in their environment.
Hydrophytes are very different in terms of their waxy cuticles; hydrophytes which are fully submerged often only have a very thin cuticle or do not have one at all whereas hydrophytes which are partially submerged have a waxy cuticle on the top of their leaf. Hydrophytes which are partially submerged have a cuticle as this prevents damage done by conditions in their environment such as wind or sun as well as prevents algae from growing on the top of the leaf. Hydrophytes which are fully submerged do not need a cuticle as they live in an environment where there is a high amount of water available, therefore unlike xerophytes and mesophytes do not have adaptations such as this which focus around conserving water.
Xylem and Phloem Adaptations
The vascular system across the three plant groups are quite similar, yet also different. Mesophytes have a vascular system which is well developed as it consists of both xylem and phloem vessels which help transport water around the plant from the roots where it is initially absorbed from. This water relies on the xylem and phloem vessels to help it travel around the plant in order to get to the areas it needs to be.
Xerophytes have a vascular system which is similar to a mesophytes as it also has both xylem and phloem vessels. Their vascular system is connected to the roots where water travels upwards to the leaves or if the xerophyte has no leaves, to the stem.
In contrast, a hydrophyte’s vascular system is quite different as it not well developed. This is because a hydrophyte lives in an aquatic environment where water is in abundance, therefore do not need a well developed vascular system like that of a mesophyte or xerophyte’s which transport water throughout the plant. A hydrophyte uses osmosis through its leaves to collect water.
Leaf Adaptations
Physical leaf adaptations vary across all three main plant groups. Leaves of a hydrophyte are dependent on how submerged the plant is. A partially submerged hydrophyte may have leaves which are large and that float on the surface of the water which helps to provide support to the plant. The leaf will also be thick so that it can prevent damage from conditions in which the plant lives in such as water movement or wind. Hydrophytes which are fully submerged will have leaves which are quite thin and also highly dissected. This lets water which contains various minerals and gases needed for survival, to be directly absorbed by the plant as the leaves have a large surface area. These leaves are also quite flexible as conditions where the plant lives may mean its exposed to water movement and/ or wind.
Mesophytic leaves are quite similar to hydrophytic leaves which are partially submerged but different to ones which are fully submerged. The size of these leaves are dependent on the environment the mesophyte is in although are generally thin and flat. Some mesophyte’s leaves may also have hairs which help to create a microclimate, therefore reducing the concentration gradient. The leaves are also green in colour due to the large amount of chloroplasts in them.
Leaves of a xerophyte are quite different compared to a mesophyte and hydrophytes. Xerophytes rarely have leaves and if they do they are rolled up. Instead xerophytes often have spikes. These spikes reduce the amount of water lost through transpiration as there is less surface area, as well as provide protection from predators as xerophytes often live in environments where competition for water is fierce, therefore they need to protect what little water they have.