Transcript for:
Adaptations of Xerophytes and Hydrophytes

welcome biologists to this session where we're going to take a look at the adaptations of xerophytes and hydrophytes so let's take a look at zerophytes to start off with one of the adaptations they have is that they can have rolled leaves now this is like the Marin grass that you would find on Sand Dunes especially on English Shore now the reason why they have rolled leaves as you can see in this picture here is because they reduce the surface area for evaporation of water vapor through the stomata they also by having these roll these is we trap a layer of water vapor in this area here now if we're trapping a layer of water babe the close to the stomata it means that we're creating a high water vapor potential outside of the stomata therefore reducing the water vapor potential gradient reducing an evaporation of water from the leaf or water vapor from the leaf it's really important for you to turn water vapor when describing these adaptations in order to get as many amounts as possible so some of them also have hairy leaves and these are exactly the same reasons why so it's a trap a layer of water vapor they create a high water vapor potential outside of the stavata therefore reducing the water vapor potential gradient and therefore reducing the evaporation of water vapor from the leaf or via the stomata foreign so as you can see in this particular example here the stomata here are in this almost like kind of pit area if you like and so normally in a in a normal Leaf it's not a zerophyte you'd find stomata kind of here on the bottom of the leaf but in the in the sentence tomato you kind of get this pit white structure on the inside so sunken's tomato and again exactly the same kind of idea is to trap a layer of water vapor so the wind or wherever it is can't take it away as easily therefore we get that high water of a potential gradient outside of the stomata reducing the water vapor potential ingredient and reducing evaporation of water vapor from the leaf the next one is we can have needle light hairs uh need a light leaves sorry and that's for reducing the surface area for evaporation of water so if you think about it this is what Christmas trees are adapted to be like the pine trees and that's because they live in such cold environments that they have reduced water availability because the water is ice so it's a bit more difficult for the trees to take up the water so therefore they reduce evaporation from the leaves by having the needle light leaves another one is that they have a dense sponging useful so this is the area here inside of the leaf now the reason why they would have a dense spongy mucibility so that it's a smaller area for evaporation of the water from the vascular bundle inside the leaf into the spongy mesophil area before the water vapor leaves the plant through the stomata other things to think about with zerophytes they have a lot of fewer stomata which will be closer in the day they're also found on the lower surface in the leaves rather than on top of the leaves to reduce evaporation again they have a very thick waxy cuticle which is waterproof and prevents any water leaving through evaporation they also have long deep roots to take up water with a high solute concentration in the root hair cells now they have a rat High solute concentration because if they have a lot of salts and ions in their hair cells this will reduce the water potential inside the roots and therefore draw more water in Via osmosis now a hydrophize they have something called erinchyma which are basically plant tissue with air spaces and this allows buoyancy because they live in water and the hydrophytes need to be able to float they also have a very very large leaves to increase the rate of photosynthesis because water is not a limiting factor for them they also have these special Roots called pneumatophores and you know because they live in water water is not a limiting Factory photosynthesis the main limiting factor here is going to be gas exchange and the gases involved needed for photosynthesis so they have these specialized roots that grow out of the water to Aid with gas exchange and therefore help to increase the rate of photosynthesis a couple more things to think about with hydrophytes they have plenty of stomata because water is not a limiting factor which will be open the majority of the Town they'll also be found on the upper surface of the leaves because the bottom of the surface of the leaf is normally in contact with the water so therefore stomatos on top of the leaves they also have a thinner waxy cuticle there's no need to try and prevent too much water leaving through evaporation and they also have a very short root system partly so they're not damaged by occurrants but also so the plant can meet its requirements for water um where it is because it lives in the water there's no need to have long extensive use to find water because it lives in water it's readily available to the plant so that's everything you need to know there on zero files and how to fights just remember when you're talking about zerophytes to mention the term water vapor and not just water guys good luck with your exams all the best and don't forget don't use the words if they amount and size use good scientific terminology to describe your answers good luck