For all varieties of plants to survive they need to have adaptations that allow them to survive in their environment. There are many factors that cause plants to develop adaptations. For some of these adaptations it is known that plants can sometimes change the way they photosynthesise, respire and transpire which can give them extra protection from various factors.
Lichens are capable of surviving in a wide range of environmental conditions and they have the ability to grow on any surface. Lichens are always usually found growing on bark, leaves, moss and also on other lichens. They can also grow on rock, walls, gravestones, roofs, exposed soil surfaces and in the soil
Lichens are composed of both a fungus and photosynthetic algae. This allows them to have a symbiotic relationship that is of equal benefit to both of them. This relationship allows them to survive in hostile environments that would be otherwise challenging for them both if they didn’t have this type of relationship. Fungus makes up 80% of the lichen and the remaining 20% is made up of algal symbionts. Lichens produce carbohydrates which is an end product in photosynthesis. This end product provides nutrition for lichens as they are capable of digesting carbohydrates. The fungus part of the Lichen has thick cell walls meaning they are able to store both water and food which are essential nutrients for the Lichen (2013.extrememarine.org.uk, 2015).
When there is any moisture available it is taken in by the fungus and undergoes a mechanical change. This change allows more light in therefor triggering algal photosynthesis. This will then provide both new food and tissue for the Lichen. However if the atmosphere is dry then the Lichen will remain dormant and not grow as it will be conserving its energy.
Venus flytrap (Dionaea muscipula)
Venus flytraps are carnivorous plants that are native to the wetlands in the North and South of Carolina in the United States. However, they are also popular as houseplants. When the flytrap is triggered it quickly snaps shut and imprisons its prey. This process can be triggered by a time and touch sensitive mechanism (Bbc.co.uk, 2015). As soon as the prey has been digested the Venus flytrap opens once again to trap another prey. Each trap on the Venus flytrap can only function three or four times, after this it photosynthesizes like a normal leaf or dies back. This particular plant thrives in an environment that has plenty of sunlight, good air circulation, high humidity and soil that is acidic and contains poor amounts of nutrients (Theflytrapisu.blogspot.co.uk, 2013).
Venus flytraps have adapted themselves to their usual wetland environment by becoming carnivores, therefore they digest all of the prey they catch. This is due to the soil in their natural habitat containing poor amounts of nutrients (nitrogen) which means they would not be able to fully support themselves off of their natural habitat.
Another adaption they have made is their ability to trap prey. This is carried out by the two leaf parts that have tiny sensitive hairs. These hairs have the ability to sense the presence of any prey that gets close to their trap. When the prey is sensed, the trap quickly closes trapping the prey. Afterwards the leaf secretes a mixture of digestive enzymes that will help to break down the prey. These enzymes will help make it easier for the plant to digest their prey. Without this the Venus flytrap would struggle to survive in the poor soil of its natural environment.
The leaves of this plant have a bendable midrib helping them to close. To help identify the prey, the edges of the leaves are lined with tooth like hairs. These hairs are very sensitive to the vibrations of insects, therefore this will notify the plant when prey are nearby.
To help lure the insects towards the Venus flytrap, the plant has a strong sweet smell of nectar. Once the prey become trapped inside, the digestive glands on the insides of the leaves release enzymes that will dissolve the prey. The hairs on the leaves lace together like fingers helping to trap the prey and allowing the enzymes to break down the prey making it more digestible.
The leaves of the Venus flytrap have the ability to photosynthesise like a normal plant and transpires by evaporation through the stomata on the leaves. The stomata also exchange carbon dioxide and oxygen.
Bell heather (Erica cinerea)
Bell heather can be found on dry moorlands and it has the ability to grow to about 60 centimetres. The small leaves are dark green and the flowers are reddish-purple that are found in groups of 2.
Heather plants have a symbiotic relationship with fungi. The fungi grows inside and between some of the heather’s root cells. The Heather benefits when there is fungi and similarly the fungi benefits from some of the plants nutrients meaning they have a symbiotic relationship. To help disperse its seeds the Bell Heather has rich nectar and pollen, helping to attract insects such as bees (Virtualheb.co.uk, 2015).
Due to the heather growing in a dry environment it cannot lose too much water as it will not be able to regain too much water. To overcome this, the leaves are thick and waxy making them tough. This helps to reduce the possibility of them tearing in windy conditions and it also reduces water loss due to the waxy layer. If tearing of the leaves were to occur it would result in a reduction of photosynthesis therefore damaging the health of the heather.
Another adaptation to prevent water loss is that the leaves have rolled edges, these edges curve inwards until they nearly meet. This adaptation helps to protect the stomata from losing water through transpiration. For added protection the undersides of leaves are covered with fine hairs helping to block any spaces where water may escape from (Electricscotland.com, 2015). Without any of these adaptations there would be little photosynthesis and respiration occurring.
Giant water lily (Victoria amazonica)
The Giant water lily originates from tropical South America. The huge circular leaves can grow to about 2.5 m across. They have upturned sides and are anchored by long stalks forming from an underground stem that is buried in the mud at the bottom of a river. The upturned sides are an important adaptation as they stop each leaf becoming trapped with one another preventing the plant from photosynthesising and transpiring. The curved edges also increase surface area helping to increase photosynthesis and transpiration.
Another adaptation is that the leaves appear to have to be quilted and have a waxy layer that enables the plant to repel water. This prevents the palnt fro, having too much water causing it to drown. The under surface of the leaves have a network of ribs clad in sharp spines. This acts as a defence mechanism against herbivorous fishes and manatees.
Another adaption to prevent the plant from drowning in the water is that the spaces between the ribs allows air to be trapped keeping the leaves afloat. To protect the plant from too much sunlight each plant produces around 40 leaves, this helps to exclude light.
Another feature of the giant water lily is that the stomata have evolved to be on the top of the leaf. This ensures transpiration can take place, if the stomata were on the underside transpiration would not be able to take place because the underside of the leaf would be lying in the water.
Pine trees (the genus Pinus)
Pine trees grow best in challenging environments, such as cold northern climates and locations renowned for forest fire. Pine trees have developed cunning adaptations that allow them to survive in most climates and challenging environments.
The fist adaptation is the Pine tree retaining its needles for three years, this extends their photosynthesis period. These trees have a tightly assembled needle structure protecting their vascular tissue therefore reducing water loss. To allow for transpiration to happen the needles are covered in a waxy cuticle preventing snow from building up.
As Pine trees mature their lower branches drop so that the tree can get maximum sunlight. This helps mature trees to survive ground fires as fires keep the underbrush from competing and choking other pine trees allowing them to remain dominant. In certain Pine species the cones will only open up and release their seeds if they detect the intense heat from a forest fire. This is because the ash from the fire will provide the seeds with the necessary nutrients needed to grow.
‘Pine needles mature in bundles, or fascicles, of long, needle-shaped leaves wrapped at the base with short, scale like leaves’ (eHow UK, 2015). To overcome the loss of trees as a result of fires, fire-resilient pines produce an abundance of seeds and cones that only open up due to intense heat.
Due to water being needed all year round Pine trees have adapted themselves to allow this function to happen even in wintery conditions when water and most things freeze. In cold conditions the main line of water transport (tracheid) can become frozen preventing the movement of water up the tree. When the water freezes the tracheid’s become broken, however the adaptation of these trees allows for ice formation permitting the repair of the tracheids instead of having to grow new ones each time. This helps the tree conserve their energy as they are not having to continuously repair themselves when the water freezes.
Arctic Poppy (Papaver radicatum)
Arctic poppies can be found in Nunavut region of Canada. They are covered in hardy and tough hairs, with a few yellow or white petals, the white petals would allow the poppy to blend in with its Antarctic conditions.
The hairs are an adaptation so that predators are warned away from the plant. These flowers continuously turn to face the sun and attract insects to the centre of their bloom. By always following the sun this increase photosynthesis as it is an input required for the process. They can be found growing in meadows, mountains and dry river beds. They are suited to growing around stones as they can absorb the sun’s heat and provide shelter for the roots of the poppies. By growing near rocks they can also absorb the moisture that surrounds the rock keeping them alive.
Due to Cacti being mainly grown in deserts they have adapted themselves to survive with desert conditions. Cactus mainly grow on rocky hillsides and in barren washes in the desert.
Firstly they have a widespread root system allowing them to go to great depths to find water. In addition to this the stems of a Cacti can store the water ensuring that there is a constant supply of water to the plant.
In addition to these features Cacti have spines instead of leaves. Spines rather than leaves allow the Cacti to conserve energy as the spines have less surface area than leaves would have. This helps to minimise water loss by the process of transpiration as well. The spines also help to protect the Cacti as they can deter any water- seeking animals away from themselves.
Many Cacti have enlarged stems, these can carry out photosynthesis and store water. These species of Cacti also have a waxy coat preventing water loss by transpiration. This waxy substance prevents water from spreading on the surface and instead encourages water down the stem and into the roots. Another factor is that Cacti have a hard-walled, thick stem that keeps water from evaporating. The stem is fleshy, green and has the ability to carry out photosynthesis.
During droughts Cacti continue to photosynthesize as they have fixed spines rather than leaves. These green stems produce the plant’s food (photosynthesis) and lose less water than leaves because of their waxy coating on the surface of the stem. The pores on Cacti during the peak of the day are shut and open at night releasing minimal amounts of water.
To overcome competition Dandelion grow a tap root with a rosette. A rosette has plenty of green leaves that grow in the formation of a circle. If any other seed tries to establish itself near the Dandelion they will not be able to do so due to the rosette’s shade. This allows the Dandelion to now obtain all the nutrients and water from the surrounding soil as there is little competition.
The rosette of a Dandelion allows them to be a perennial (living throughout the year). A new rosette is formed in the winter months allowing the dandelion to have a head start over non-perennial plants.
The tap root acts as a storage site for nutrients. This means that when the flower part is eaten or mowed over the tap root will always be able to grow into a new flower. This helps to increases their survival rates.
Dandelions have very few leaves this is to reduce transpiration through the stomata. Photosynthesis also occurs in the leaves and this is to produce food for the plant that is then stored in its tap root. To discourage animals away, Dandelions have a strong unpleasant smell preventing them from being eating by animals.
Prairie grass has had to adapt over many of years due to years of droughts, fires and grazing by animals.
Prairie plants have roots that are capable of extending downwards to about 3.5 meters. This allows the roots to form networks that are deep enough in the soil to absorb moisture during periods of droughts. This is necessary as the grass grows in dry grassland areas that are susceptible to droughts. To overcome fires Prairie grass main growing point is underground as this allows the grass to survive any fire and to be able to regrow if necessary.
Prairie grasses have narrow leaves which ensure they lose the least amount of water possible through transpiration than broad leaves would. It is important that there is good water retention as the environment is dry and known for droughts.
To help Prairie grass survive and reproduce they are brightly coloured. This helps to attract pollinators such as bees, wasps and birds which can carry out seed dispersal for the grass.
Due to grasslands being very windy the grass takes advantage of the wind and allows itself to be wind pollinated. However to overcome the windy conditions the stems of the prairie grass are flexible allowing them to bend in strong windy conditions (Mbgnet.net, 2015).
After researching various plants it has been highlighted that every plant is different with their adaptations for surviving in their individual environment. Venus flytrap’s have adapted themselves to be carnivores to survive in their wet environment whereas Pine trees have overcome their cold environment by allowing for ice formation that permits the repair of the tracheid instead of having to grow new ones each time.
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