1. Leaf structure Mineral requirements

2. Cross section of a leaf Xylem/ Phloem Stomata
2 guard cells control the opening and closing of stomat

3. Function of leaf parts (Review)
Structure
Function
Epidermis
Top thin layer (protective). Prevents water loss and over heating of leaf
Cuticle
Waxy layer of the epidermis- Prevents water loss and over heating of leaf
Spongy Mesophyll / Palisade cells
Photosynthesis – there are more chloroplast in the palisade cells than the mesophyll cells are- this is where the majority of photosynthesis happens. Palisades are long – to maximize surface area. Spongy cells are round and few – allows for air to travel to the palisade cells (gas exchange)
stomata
Allows air to come in and out of leaf ( gas exchange)
Guard cells
Control the opening and closing of stomata
Vascular bundle
Has the xylem and phloem running through the leaf
xylem
Transports water into the leaf / structural support
phloem
Takes substance away (sugar) that the leaf has made to other pars of the cell / structurally support

4. Mineral Requirements
Plants can use the carbohydrates they make to make protein.
Proteins – C/H/O/ & N (Nitorgen)
Plants get their nitrogen from inorganic compounds like nitrate ions and ammonia ions.
Even though 80% of air is nitrogen oxide – it is mostly useless to plants as it is unreactive
Nitrates (NO3- / NH4+) taken up by roots
If not enough nitrates – can’t make protein / can’t make new cells
The plant will have stunt (short) growth / weak

5. Nitrates are needed to make enzymes for the plants
Smaller / less green / less healthy
Farmers can supplement this by adding nitrates to the soil in form of fertilizer
Magnesium ions:
Needed to make green pigment in chlorophyll
Plant leaves become yellow if magnesium not there quickly
Efficiency of photosynthesis goes down