● The `color{violet}("epidermal tissue system")` forms the outer-most covering of the whole `color{violet}("plant body")` and `color{violet}("comprises")` `color{brown}("epidermal cells, stomata")` and the `color{brown}("epidermal appendages")` – the trichomes and hairs.
`star` `color{green}("Epidermis:")`
● The `color{brown}("epidermis")` is the outermost layer of the `color{violet}("primary plant body").`
● It is made up of `color{violet}("elongated,")` compactly arranged `color{violet}("cells,")` which form a `color{violet}("continuous layer.")`
● Epidermis is usually `color{violet}("single layered.")`
● `color{violet}("Epidermal cells")` are `color{violet}("parenchymatous")` with a small amount of `color{violet}("cytoplasm")` lining the cell wall and a `color{violet}("large vacuole.")`
● The outside of the `color{violet}("epidermis")` is often covered with a waxy thick layer called the `color{brown}("cuticle")` which prevents the `color{violet}("loss of water.")`
● `color{violet}("Cuticle")` is absent in `color{violet}("roots.")`
`star` `color{green}("Stomatal Apparatus:")`
● `color{brown}("Stomata")` are `color{violet}("structures")` present in the `color{violet}("epidermis ")` of leaves.
● `color{violet}("Stomata")` regulate the process of `color{violet}("transpiration")` and `color{violet}("gaseous exchange.")`
● Each `color{violet}("stoma")` is composed of two `color{violet}("bean shaped cells")` known as `color{brown}("guard cells.")`
● In grasses, the `color{violet}("guard cells")` are `color{violet}("dumbbell shaped.")`
● The outer walls of `color{violet}("guard cells")` (away from the `color{brown}("stomatal pore")` ) are thin and the `color{violet}("inner walls")` (towards the stomatal pore) are highly thickened.
● The `color{violet}("guard cells")` possess `color{violet}("chloroplasts")` and `color{violet}("regulate ")` the opening and closing of `color{violet}("stomata.")`
● Sometimes, a few `color{violet}("epidermal cells,")` in the vicinity of the `color{violet}("guard cells")` become specialised in their `color{violet}("shape")` and `color{violet}("size ")` and are known as `color{brown}("subsidiary cells")`.
● The stomatal aperture, `color{violet}("guard cells")` and the surrounding `color{violet}("subsidiary cells")` are together called `color{brown}("stomatal apparatus")`
`star` `color{green}("Root Hairs and Trichomes:")`
● The `color{violet}("cells of epidermis bear")` a number of hairs.
● The `color{brown}("root hairs")` are `color{violet]("unicellular elongations")` of the `color{violet}("epidermal cells")` and help absorb water and minerals from the `color{violet}("soil.")`
● On the stem the `color{violet}("epidermal hairs")` are called `color{brown}("trichomes.")`
● The `color{violet}("trichomes")` in the `color{violet}("shoot system")` are usually multicellular.
● They may be branched or `color(violet}("unbranched")` and `color{violet}("soft or stiff.")`
● They may even be secretory.
● The `color{violet}("trichomes")` help in preventing `color{violet}("water loss")` due to transpiration.
● The `color{violet}("epidermal tissue system")` forms the outer-most covering of the whole `color{violet}("plant body")` and `color{violet}("comprises")` `color{brown}("epidermal cells, stomata")` and the `color{brown}("epidermal appendages")` – the trichomes and hairs.
`star` `color{green}("Epidermis:")`
● The `color{brown}("epidermis")` is the outermost layer of the `color{violet}("primary plant body").`
● It is made up of `color{violet}("elongated,")` compactly arranged `color{violet}("cells,")` which form a `color{violet}("continuous layer.")`
● Epidermis is usually `color{violet}("single layered.")`
● `color{violet}("Epidermal cells")` are `color{violet}("parenchymatous")` with a small amount of `color{violet}("cytoplasm")` lining the cell wall and a `color{violet}("large vacuole.")`
● The outside of the `color{violet}("epidermis")` is often covered with a waxy thick layer called the `color{brown}("cuticle")` which prevents the `color{violet}("loss of water.")`
● `color{violet}("Cuticle")` is absent in `color{violet}("roots.")`
`star` `color{green}("Stomatal Apparatus:")`
● `color{brown}("Stomata")` are `color{violet}("structures")` present in the `color{violet}("epidermis ")` of leaves.
● `color{violet}("Stomata")` regulate the process of `color{violet}("transpiration")` and `color{violet}("gaseous exchange.")`
● Each `color{violet}("stoma")` is composed of two `color{violet}("bean shaped cells")` known as `color{brown}("guard cells.")`
● In grasses, the `color{violet}("guard cells")` are `color{violet}("dumbbell shaped.")`
● The outer walls of `color{violet}("guard cells")` (away from the `color{brown}("stomatal pore")` ) are thin and the `color{violet}("inner walls")` (towards the stomatal pore) are highly thickened.
● The `color{violet}("guard cells")` possess `color{violet}("chloroplasts")` and `color{violet}("regulate ")` the opening and closing of `color{violet}("stomata.")`
● Sometimes, a few `color{violet}("epidermal cells,")` in the vicinity of the `color{violet}("guard cells")` become specialised in their `color{violet}("shape")` and `color{violet}("size ")` and are known as `color{brown}("subsidiary cells")`.
● The stomatal aperture, `color{violet}("guard cells")` and the surrounding `color{violet}("subsidiary cells")` are together called `color{brown}("stomatal apparatus")`
`star` `color{green}("Root Hairs and Trichomes:")`
● The `color{violet}("cells of epidermis bear")` a number of hairs.
● The `color{brown}("root hairs")` are `color{violet]("unicellular elongations")` of the `color{violet}("epidermal cells")` and help absorb water and minerals from the `color{violet}("soil.")`
● On the stem the `color{violet}("epidermal hairs")` are called `color{brown}("trichomes.")`
● The `color{violet}("trichomes")` in the `color{violet}("shoot system")` are usually multicellular.
● They may be branched or `color(violet}("unbranched")` and `color{violet}("soft or stiff.")`
● They may even be secretory.
● The `color{violet}("trichomes")` help in preventing `color{violet}("water loss")` due to transpiration.