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									Tropical Morphology
How Plants Adapt Rain Forest




                                   Leaf
                                Structures
                               Extreme Adaptation

                           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 describe 3 ways tropical plants
  conserve water, and 3 ways plants manage extreme
  light levels found in the tropics

• 2. Be able to describe why plants that live in a
  rainforest region might have to conserve water, or
  manage very high light levels.
Extremes in The Rainforest
 Tough Places for Rainforest Plants
• 1. The top of the plant canopy in a rainforest:
   – Very high light
   – Frequent high winds
   – Very hot leading to rapid drying

• 2). Dry slopes:
   – As warm, moist air rises over mountains, it loses its
     moisture as rain. The side facing the air current
     becomes a rainforest. The other side of the mountain
     is very dry and become desert-like. Thus some desert-
     like conditions are often nearby rainforests.
  Dealing With Tropical Winds
Bananas have leaves that can
tear in high wing with without
affecting photosynthesis.
Tearing reduces wind force on
the entire plant preventing it
from toppling in storms.
     Palms Are Coastal Survivors

Palms often grow in windy,
coastal areas. Like
bananas, they have
specialized leaves that
allow wind to pass through
without exerting a big
force against the plant.
This is how palms survive
hurricanes.
Waxy Cuticle
Water Conservation
Cuticle and Storage
                Heat and Wind




Many orchids live at the top of the
rainforest canopy. It can be dry,
very hot and windy in the tops of
the rainforest trees.
              High Light Avoidance




Light colored leaves reflects light, and tiny hairs reduce wind
passing over the leaflets and thus reduces drying effects of wind.
                High Light Avoidance




Tiny, hair-like leaves   Vertical, waxy leaves   Vertical, ribbon leaves
                    Modified Leaves




The string –o-pearls plant has modified leaves that are curled up to form a ball.
This greatly reduces evaporation effects by wind and exposure to the sun’s heat.
      High Light, High Heat, Wind and
           Predation Protection




Cacti must be experts at leaf modification as they store water, thus
being a good food source for animals. Spines and needles reduce
foraging, while waxy layers and vertical leaves reduce water loss.
                Summary
We have seen that there are three very distinct
regions of land in Costa Rica. Plants in the
rainforest areas adapt to high rainfall, plants
on the dry side of the mountains adapt to hot
dry conditions. These adaptations to dry, hot
windy conditions include waxy cuticle, vertical
facing leaves, leaves that store water, leaf
designs that reduce wind force, and leaves
that are so modified that they don’t look like
leaves!
       Assessment Opportunity
• Describe three ways plants in a rainforest
  region that is dry adapt to the hot , dry and
  windy tropical conditions.

• Find a map of Washington State. Can you
  determine the wet and dry regions of the
  state? Did mountains play a role? Now look at
  a map of Costa Rica. Are they similar? What’s
  different?
        For Future Exploration
• http://www.nps.gov/cany/forteachers/upload
  /FifthGrade_PlantAdaptations.pdf

• http://en.wikipedia.org/wiki/Orchid

• http://www.cactusmuseum.com/survival.asp

								
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