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IB Biology HL - Plants Topic
Leaf structure
label the parts ....
Write three comparisons between monocotyledons & dicotyledons
Tissue Plan Diagrams of Dicotyledon
Stem
Explain why the specialised part of a leaf carry out each function
·absorption of light,
·gas exchange,
·support,
·water conservation, and
·the transport of water and
·transport of the products of photosynthesis.
What are the main features of
monocotyledons ?
A panda walks into a café. He orders a sandwich, eats it, then draws a gun and proceeds to fire it at the other patrons.
'Why?' asks the confused, surviving waiter amidst the carnage, as the panda makes towards the exit. The panda produces a
badly punctuated wildlife manual and tosses it over his shoulder.
'Well, I'm a panda', he says, at the door. 'Look it up.'
The waiter turns to the relevant entry in the manual and, sure enough, finds an explanation. 'Panda. Large black-and-white
bear-like mammal, native to China. Eats, shoots and leaves.'
Meristems generate new cells for growth of the plant.
Apical meristems cause the stem and root to get longer.
They can be found at the top of the shoot and at the tip of the root.
Lateral Meristems produce the xylem and
the phloem in the stems and roots.
In trunks of trees the xylem produced
causes rings of growth - and thickening of
the trunk.
http://www2.puc.edu/Faculty/Gilbert_Muth/
art0062.jpg
Auxin is a plant growth substance that
causes phototropism.
Auxin is made by the cells in shoot tips.
It then diffuses down both sides of the
shoot. The auxin collects on the dark
side of the shoot. Auxin stimulates cell
elongation on the dark side of the shoot
and causes shoots to grow towards
light.
End of this section .....
THICK waxy cuticle
stomata
Vascular bundle (xylem &
phoem)
stomata in PITS
Hairs on leaf - reduce air flow
leaf rolled up
stomata
leaf
succulent
true leaf
dicotyledonous seeds
two cotyledons
seed leaves -
embryo
true leaf
cotyledon
radicle - "embryo root"
cotyledons