The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system...
-
Upload
toby-brookins -
Category
Documents
-
view
235 -
download
2
Transcript of The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system...
![Page 1: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/1.jpg)
The leaf is the main photosynthetic organ of most vascular plants
Leaves - Overview
Shootsystem
LeafBlade
Petiole
Leaves generally have a flattened blade and a stalk called the petiole, which joins the leaf to a node of the stem
![Page 2: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/2.jpg)
Most Dicots have branch-like veins and palmate leaf shape
Monocots have parallel leaf veins and longer, slender blades
Leaves - Comparisons
Monocots and Dicots differ in the arrangement of veins, the vascular tissue of leaves
![Page 3: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/3.jpg)
LEAF PARTS
1. Stoma (stomata) – small pores that act as a doorway for gases involved in photosynthesis (found mainly on the underside of leaves).
2. Guard Cells – Cells that regulate the opening of the stomata.
3. Lower and upper epidermis – outer layer of a plant that serves for protection, like skin.
![Page 4: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/4.jpg)
LEAF PARTS CONTINUED…
4. Palisade layer – layer where majority of chloroplasts are found (site of photosynthesis).
5. Spongy layer – cells surrounded by air spaces; allow water, CO2 and O2 to diffuse during photosynthesis.
6. Waxy layer/cuticle – protects leaf from water loss and from feeding insects.
![Page 5: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/5.jpg)
Leaves – Structure and Development
• Most dicots have 2 types of mesophyll– Palisade
mesophyllhigh
photosynthesis– Spongy
mesophyllair spaces for gas
& water exchange
• Monocot leaves have 1 type of mesophyll
![Page 6: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/6.jpg)
CROSS SECTION OF A LEAF
![Page 7: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/7.jpg)
Leaves – Structure and Development
• Leaves are several layers thick – each with different cell types
![Page 8: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/8.jpg)
Epidermis Leaves• Leaf epidermis contains stomata - allow CO2
exchange • Stomata flanked by two guard cells, control open vs.
closed• The ground tissue in a leaf, called mesophyll, fills the
middleKey
to labels
Dermal
Ground
VascularCuticle Sclerenchyma
fibersStoma
Bundle-sheathcell
Xylem
Phloem
(a) Cutaway drawing of leaf tissuesGuardcells
Vein
Cuticle
Lowerepidermis
Spongymesophyll
Palisademesophyll
Upperepidermis
Guardcells
Stomatalpore
Surface view of a spiderwort(Tradescantia) leaf (LM)
Epidermalcell
(b)
50 µ
m1
00
µm
Vein Air spaces Guard cells
Cross section of a lilac(Syringa)) leaf (LM)
(c)
![Page 9: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/9.jpg)
VASCULAR TISSUE
Xylem – cells that carry water and dissolved minerals from the roots to the leaves.
Phloem – cells that carry food (sugar) that is made in the leaves to all parts of the plant.
Use: Collectively the vascular tissue, xylem and phloem create a vein or vascular bundle to transport material in plants.
![Page 10: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/10.jpg)
STOMA OPEN VS. CLOSED
Open – with light and when guard cells are filled with water.
Closed – without light and when guard cells are lacking water (dehydrated).
Why is it important to have stomata open?
Closed vs. Open
![Page 11: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/11.jpg)
![Page 12: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/12.jpg)
![Page 13: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/13.jpg)
![Page 14: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/14.jpg)
![Page 15: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/15.jpg)
![Page 16: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/16.jpg)
![Page 17: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/17.jpg)
![Page 18: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/18.jpg)
![Page 19: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/19.jpg)
![Page 20: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/20.jpg)
![Page 21: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/21.jpg)
![Page 22: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/22.jpg)
![Page 23: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/23.jpg)
![Page 24: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/24.jpg)
![Page 25: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/25.jpg)
Question time????????
![Page 26: The leaf is the main photosynthetic organ of most vascular plants Leaves - Overview Shoot system Leaf Blade Petiole Leaves generally have a flattened blade.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649cad5503460f9496efa6/html5/thumbnails/26.jpg)