Download Morphology 4 - University of Georgia

Tropical Morphology
How Plants Adapt Rain Forest
Leaf
Structures
Light Management Strategies
The University of Georgia
College of Agricultural and Environmental Sciences
About The Author
• Dr. Paul A. Thomas
– Professor of Floriculture
– Department of Horticulture
– The University of Georgia
– Extension Specialist
– Really into Photography!
Learning Objectives
• 1. Be able to decribe the ways plants manage light
within their own canopy zone to enhance their own
survival in low light conditions within the rainforest
• 2. Describe what a typical rain forest tree canopy
looks like in cross section, and explain why this is so.
Rain Forest Canopy
Maintains Leaves Only
Where There Is Light
Rapid New Growth When Sunlight Is Present
Epiphytic Growth On Branches
Epiphytic Growth on Stems/Trunk
Light Capture Strategy
Radial Distribution of Leaves
Leaflets that can raise up or go flat
depending on light levels.
Overlapping radial leaves
Staggered Leaflets allow leaflets to
turn toward the light
Stagger Leaves –
Larger the
spaces, the more
likely the plant
grows near the
forest floor.
Perforated Leaves
Allowing light to
pass through
otherwise large
leaves is how
Philodendron
shares light with
leaves lower down
on its stem.
More Off-Set Leaves
A great place to study
tropical leaf morphology!
Summary
We have seen that there are many different
ways plant leaves can adapt to the relative
lack of light under the forest canopy, or to the
hot, intense tropical sunlight at the canopy.
Leaf staggering, or light-sharing is a common
approach to forest floor plants and vines that
must collect every scrap of light that makes it
down to the forest floor.
Assessment Opportunity
• Explain how leaf orientation can help increase or
decrease light being received by the plant.
• How does having leaflets with the ability to bend
towards light help forest floor plants?
• Which do you think is a more successful strategy?
Being an epiphyte or eventually growing up to
being a tall canopy tree? What are the
advantages and disadvantages of both strategies?
For Future Exploration
• http://reocities.com/RainForest/5798/levels.h
tml
• http://en.wikipedia.org/wiki/Phyllotaxis