Transcript Leaves

Leaves - II
Corn leaves show Kranz anatomy
Photosynthesis
• Light Reactions produces ATP and
NADPH
• Carbon fixation reaction incorporates CO2
into sugars
– Normal fixation is by Calvin Cycle: C-3
pathway
• CO2 + Ribulose-1,6-bisphosphate forms 2
molecules of PGA
– C-4 plants prefix CO2 into oxaloacetic acid
and malic acid prior to the Calvin Cycle
Calvin Cycle (C-3)
C-3 plant leaves
C-4 pathway
Sugar Cane Leaf
Grama grass leaf (C-4)
Corn leaf
Amaranth Leaf (C-4 dicot)
Schematic of Atriplex leaf (a C-4 dicot)
1 = vascular
bundle
2 = bundle sheath
cell
3 = radially
arranged palisade
mesophyll (Kranzmesophyll) cell
4 = water-storage
parenchyma cell
5 = stomatal
complex
6 = sub-stomatal
cavity
7 = cuticle of
adaxial epidermis
Adaptations to Xeric
Environments
Thickened cuticle
Sunken stomata
Beach grass
Yucca
Oleander has many xeromorphic adaptations
Ficus
Succulency
Succulents
Lithops
Saguaro cactus
Hydrophytes
Nymphae spp
Nymphae leaves
Elodea
Potamogeton
Floating leaf
Submerged leaf
Submerged Vallisneria leaf
Gymnosperm leaves
Pine needles
Pine
Cooksonia earliest vascular plant
Evolution of microphylls as enations
Evolution of Megaphylls by
•Overtopping
•Plannation
•Webbing