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Interior structure of a leaf - Coggle Diagram
Interior structure of a leaf
upper epidermis
transparent to allow light to pass through
waxy cuticle
keeps moisture in
keeps fungi and bacteria out
palisade mesophyll
contains tightly packed cells to minis light that passes through
in a vertical orientation to mean that it can absorb light through its whole length
as much as possible gets absorbed
contains a high concentration fo chloroplasts for photosynthesis
sight of most phtosynthesis
lower epidermis
the guard cells open and close the stomata
stomata
regulate gas exchange through diffusion
co2 in
o2 out
close to avoid evaporation of water (transpiration)
only open when the conditions are right for photosynthesis to avoid water loss
spongy mesophyll
air spaces to allow for gas exchange and diffusion of gasses (movement of co2 to the palisade mesophyll of photosynthesis, and the movement of 02 out as a waste product)
some chloroplasts to absorb any light that is not absorbed by the palisade mesophyll
contains the xylem and phloem, also called vascular bundle
xylem
transportation of water for photosynthesis
This is caused by waterless from the aerial surface of plants by evaporation (transpiration)
this means that there is a negative pressure of water in the leaves
water is drawn in from the root hair cells (by osmosis) and up through the xylem due to the concentration gradient and the low pressure.
this also bring mineral ions such as magnesium and potassium
Water moves cell to cell (in the root hair cells) by osmosis down a concentration gradient
Factors affecting transpiration
Light intensity
more light means that the stomata are more open
and more water evaporates
Heat
more heat means that the water evaporates faster, increased ke = increased evaporation
Windspeed
a higher windspeed removes the humid air around the stomata, increasing the conc gradient and therefore diffusion
humidity
more humidity decreases transpiration because there is a lower concentration gradient
phloem
movement off glucose to other parts of the plant for growth