Sources used:

• ESA Study Guide, Chapter 24: Plant Nutrition , Chapter 26 : Transpiration 
• NCEA Level 2 Life Processes, Life Processes: Cells, Adaptions
• Patterns of Lifework Book, NCEA Level 2 Biology
• http://www.everything-ponds.com/hydrophytes.html
• http://science.yourdictionary.com/hydrophyte
• http://www.tutorvista.com/content/biology/biology-iv/organisms-environment/hydrophytic-habitat.php#hydrophytes
• http://www.tutorvista.com/content/biology/biology-i/environment/adaptation-plants.php
• http://en.wikipedia.org/wiki/Xerophyte#Physiological_adaptations
• http://www.terradaily.com/reports/How_some_leaves_got_fat_Its_the_veins_999.html

Hydrophytes , Mesophytes and Xerophytes all have specialised adaptations which allow them to maintain water balance in different environments for their survival . Hydrophytes for example have specialised adaptations to maintain water balance to survive in a water rich environment , whereas xerophytes have specialised adaptations to maintain water balance in order to survive in an environment with a lack of water .

LEAVES:

Hydrophytes , Mesophytes and Xerophytes all have leaves which contain stomata and a waxy cuticle . Hydrophytes that are fully submerged have no stomata or waxy cuticle as these are not required , instead stomata and the waxy cuticle are found on floating parts of the leaf , by having stomata and the waxy cuticle on the floating part of the leaves it allows efficient gas exchange and prevents excess transpiration on very hot days , so hydrophytes can successfully maintain a water balance that is optimum for successful photosynthesis and respiration . In contrast xerophytes have a very thick waxy cuticle and few stomata , by having few stomata and thick waxy cuticle xerophytes are able to slow the rate of transpiration and to reflect light therefore keeping the plant cool , this allows xerophytes to maintain a water balance that is optimum for successful photosynthesis and respiration . Mesophytes also have stomata and a waxy cuticle on both the lower and upper epidermis to prevent excess transpiration on hot days or in wind , the stomata are located on the lower epidermis which is cool , so therefore reduces transpiration , this allows mesophytes to maintain a water balance that is optimum for successful photosynthesis and respiration .

Both mesophytes and xerophytes both lose their leaves in extreme weather conditions . Mesophytes that experience to snow or extremely cold weather , lose all their leaves and become dormant when exposed to these conditions , by losing their leaves and becoming dormant, mesophytes reduce the rate of transpiration , photosynthesis and respiration , this allows them to maintain a water balance at which they can survive and are therefore able to survive in periods extreme cold / snow . Xerophytes however lose their leaves and become dormant in periods of extreme heat or dry , such as droughts , by losing their leaves and becoming dormant, xerophytes are able to reduce the rate of transpiration , photosynthesis and respiration , this allows them to also maintain a water balance at which they can survive and are therefore able to survive in periods or extreme heat / dry .

CELLS:

Hydrophytes , Mesophytes and Xerophytes all have specialised tissue , which has different adaptations to allow photosynthesis and respiration to be carried out . Hydrophytes and Mesophytes both have air spaces around their leaf cells , by having very large air spaces around their leaf cells , hydrophytes aid the buoyancy of the leaves , so are able to get closer to the surface for photosynthesis , this also facilitates the diffusion of minerals and gases , and are therefore able to maintain water balance optimum for successful photosynthesis and respiration . By having air space around their leaf cells , mesophytes allow light to be reflected from spongy mesophyll , up to the palisade layer where it can be absorbed and used for photosynthesis . In comparison xerophytes , such as succulents have special tissue which store water , by having tissue which store water xeropyhtes are able to maintain a water balance which is optimum for successful photosynthesis and respiration , as the stored water can be used in droughts or when there is no moisture in the soil or air .

ROOTS:

Hydrophytes and Xerophytes both have roots which are specifically adapted to the environments in which these plant live . Hydrophytes usually have small roots , as minerals and gases that are needed for photosynthesis and respiration are dissolved in surrounding water and diffused directly in the leaves , so therefore roots are only needed for anchorage and stability , by having small roots hydrophytes are able to maintain a water balance which is optimum for successful photsynthesis and respiration , as the roots are not needed for diffusion of minerals and gases therefore they don't absorb water as this is in excess . In comparison to many xerophytes which have very deep root systems , which are able to absorb water deep in soil/sand , by having deep root systems xerophytes are to

absorb all available water and are therefore able to maintain a water balance which is optimum for successful photosynthesis and respiration . Cacti which are xerophytes have very shallow root systems , which absorb water in the top layers of soil / sand , by having shallow roots cacti are able to also absorb most available water , and are therefore able to maintain a water balance which is optimum for successful photosynthesis and respiration.

Xerophytes:

Xerophytes are plants that live in arid/dry environments, such as desserts, beaches and alpine regions . Examples of xerophytes include cacti and succulents. Xerophytes have a shortage of water , so have special adaptive features to store and/or reduce the loss of water, so that photosynthesis and respiration can be carried out .

Xerophytes have a reduced number of stomata , also the stomata are in sunken 'pits' in the lower epidermis, this traps moist air around the stomata and therefore reduces transpiration. Xerophytes have very small , rolled leaves which again traps moist air around the stomata and decreases surface area to volume ratio , therefore decreases the rate of transpiration . some xerophytes such as cacti have spines instead of leaves which significantly reduces the amount of transpiration as there are no stomata . By having few stomata and small rolled leaves , xerophytes are able to maintain water balance , as the rate of transpiration has been decreased .

Xerophytes also have an extremely thick waxy cuticle and lightly coloured hair on the epidermis of the leaves, which reduces transpiration by reducing the gradient of diffusion, as the hair lowers the wind movement surrounding the stomata, it also reflects some of the heat as it is white and shiny , so therefore helps to keep the plant cool . By having a extremely thick waxy cuticle and lightly coloured hairs on the epidermis , xerophytes are able to maintain water balance , by reducing transpiration and also keeping the plant cool , to prevent further transpiration.

Most xerophytes have very deep root systems that penetrate deep into the soil / sand (vertically), they are able to absorb any water present which is then transported by the xylem and phloem (vascular bundle) to the leaves , to be used for photosynthesis and respiration , however some xerophytes such as cacti have very shallow roots , which are able to absorb any water in the top layers or soil/ sand , which is then used for photosynthesis and respiration .By having deep root systems , xerophytes are able to maintain water balance which is optimum for successful photosynthesis and respiration, as the roots are able to absorb water in the soil / sand , which can then be used for photosynthesis and respiration.

In droughts or periods of extreme heat / dryness , xerophytes lose their leaves and become dormant , to reduce transpiration and because there is a lack of moisture in the air . Also some xerophytes such as succulents have special adaptive tissues in their stems , which store water , which can then be used in droughts , or when there is no moisture in the air or soil . having specialised adaptive tissue that stores water , allows xerophytes to maintain water balance at which they can survive in droughts , or when there is a lack of moisture in the air or soil / sand .

 

veins stained purple contain water . 

photos from:

http://archive.bio.ed.ac.uk/jdeacon/microbes/

http://www.bbc.co.uk/bitesize/higher/biology/genetics_adaptation/maintaining_water_balance/revision/4/

http://www.tynemouth.frankgillings.com/marram.html

Mesophytes:

Mesophytes are plants that grow in environments which don't usually have extreme weather conditions such a heat or dryness. Examples of mesophytes include roses and flax. Mesophytes typically transpire during the day or in when it is windy , so they have special adaptive features to prevent water loss so that photosynthesis and respiration are able to be carried out . 

Mesophytes usually have a waxy cuticle on both the upper and lower epidermis to reduce water loss through transpiration. Also stomata on mesophytes are only present on the lower epidermis , also the stomata close in extreme heat or wind to prevent transpiration , this is due the guard cells around the stomata which close when the plant starts to wilt and therefore force the stomata closed and prevent an water loss. By having waxy cuticle on the upper and lower epidermis , and stomata on the lower epidermis , mesophytes are able to maintain water balance , by reducing the rate of diffusion by the leaves .

Mesophytes also have air spaces around their leaf cells , especially around the spongy mesophyll layer , which facilitates the diffusion of gases such as oxygen and carbon dioxide , and water vapour , which are then used for photosynthesis and respiration . The air spaces in the spongy mesophyll also reflect light back up to the palisade layer (main site of photosynthesis) , which allows maximum light absorption for photosynthesis . 

Mesophytes have an extensive root system which allows both water and minerals to be absorbed from the soil and transported by the xylem and phloem (vascular bundle) to be used for photosynthesis and respiration . By having an extensive root system , mesophytes are able to maintain water balance which is optimum for successful photosynthesis , as the roots absorb both water and minerals from the soil , which are then transported through-out the plant.

Mesophytes , such as deciduous trees and shrubs that live in areas which often experience snow , lose their leaves during winter and become dormant (extremely cold weather) , because the water in the soil is often frozen so therefore cannot be absorbed by the plant , also by losing their leaves they reduce the rate of transpiration . By losing their leaves and becoming dormant , mesophytes maintain a water balance at which the plant is able to survive in extreme weather conditions (snow).

photos from:

http://www.123rf.com/photo_16589607_light-pink-rose-in-the-summer-sunny-day.html

http://www.biologymad.com/master.html?http://www.biologymad.com/planttransport/planttransport.htm

http://www.dreamstime.com/photos-images/summer-collage.html

Hydrophytes: 

Hydrophytes are plants that grow or live submerged in lakes , ponds , swamps and rivers . Examples of hydrophytes include water lilies and elodea . Hydrophytes have a shortage of oxygen and an excess of water , so they have special adaptations to allow oxygen and water to be used for photosynthesis and respiration . 

                                          

Hydrophytes which are fully submerged, such as elodea have very thin leaves to increase the surface area to volume ratio , which increases the rate of diffusion of minerals and gases (CO₂ and O₂) into the plant cells to be used for respiration and photosynthesis. Also hydrophytes that are fully submerged have no stomata or waxy cuticle as these are not required, instead stomata and the waxy cuticle are found on floating parts of the leaf to allow efficient gas exchange and to prevent excess water loss on very hot days, if the stomata and waxy cuticle were present on submerged leaves, they may be dense and therefore effect the buoyancy of the lea , sometimes a very thin cuticle is present on submerged leaves to prevent algae, but still allows photosynthesis . By having very thin leaves with no stomata and a thin waxy cuticle , or leaves with stomata and waxy cuticle only on the floating tissue , hydrophytes are able to maintain a water balance at which they are can diffuse minerals and gases and prevent excess transpiration .

Hydrophytes have very large air spaces around their leaf cells , especially the spongy and palisade (mesophyll) layers , this aids buoyancy in the leaves , so therefore they are closer to the surface for photosynthesis , it also facilitates diffusion of minerals and gases for photosynthesis and respiration. By having large air spaces around their leaf cells , hydrophytes are able to maintain a water balance at which minerals and gases can be diffused into the leaf , and also allows the leaf to float for optimum photosynthesis .

Hydrophytes usually have small roots because minerals and gases which are needed for respiration and photosynthesis are dissolved in the surrounding water , or diffused into the small thin leaves that are adapted specifically to allow diffusion , so therefore the roots are only needed for anchorage and stability , for example water caltrop  and giant water lilies .By having small roots hydrophytes are able to maintain a water balance which is optimum for successful photosynthesis and respiration , as the roots are not needed for diffusion of minerals and gases, so therefore they don't absorb water as this is in excess .

 

photos from:

http://www.flickr.com/photos/7294954@N02/485253237/

http://en.wikipedia.org/wiki/Elodea

http://ladyjskincare.blogspot.co.nz/2011/07/beauty-obsession-of-day-water-lilies.html