Plant Responses
and
Adaptations
Plant Adaptations
Plants have adaptations to help them survive (live and grow) in different areas. Adaptations - features that allow a plant or
animal to live in a particular place or habitat.
Adaptations of Plants
1. Absorbing Nutrients –absorb mineral nutrients from soil. (roots)
2. Preventing Water Loss -cuticle – watertight, waxy outer covering
-epidermis – outer layer of plant
-stomata –small openings
guard cells – cells around stomatas which help them to open.
3. Reproducing on Land –use pollen to reproduce
Adaptations of Plants4. Advantages of Conducting Tissues
- Vascular plants have a system of well-
developed tissues that transport water in a
plant.
5. Advantages of seeds
- Protection
- Nourishment
- Dispersal
- Delayed growth
6. Advantages of Flowers – Color/ scent help with pollination (reproduction)
WHAT ARE SOME ADAPTATIONS IN DIFFERENT
HABITATS?
Desert Adaptation
This plant has a waxy coating on its leaves to prevent water loss.
This cactus displays light-colored hair that helps shade the plant and hair to help shade the plant, reducing water loss.
Tropical Rainforest Plant Adaptation
Drip-tips on leaves help shed excess water.
Prop roots help support plants in the shallow soil.
Temperate Rainforest Plant Adaptation
Epiphytes live on other plants to reach the sunlight. Trees can grow very
tall in this very moist environment.
Temperate Deciduous Forest
Wild flowers grow in the spring before trees grow their leaves.
In the autumn, deciduous trees drop their leaves to minimize water loss.
Temperate Deciduous Forest Plant Adaptations
Many trees have thick bark to protect against cold winters .
Broad leaves can capture a lot of sunlight for a tree.
Plant Growth & Responses
1. Plant cells produce hormones which are chemical messengers that travel throughout plant causing other cells called target cells to respond.
2. In plants, hormones control:
a) Plant growth & development
b) Plant responses to environment
c) Flower Blooming
Hormone-producing
cells
Target cells
Movement of hormone
A. Hormone Action on Plants
Cells in one blooming flower signals other blooms using hormones to open.
B. Plant cells will send signals to one another to tell them:1. When trees to drop their leaves.
2. When to start new growth.
3. When to cause fruit to ripen.
4. When to cause flowers to bloom.
5. When to cause seeds to sprout.
Leaf DropFruit Ripening
Sprouting Corn Seeds
Cactus BloomingTree Budding
Important Hormones
1.Gibberellins - responsible for plants growing into adult plants and flower growth
2.Ethylene – causes fruits to ripen
3.Auxins - responsible for geotropisms and phototropisms
Ethylene released by apples and tomatoes causes fruit to age quickly.
D. Plant TropismsTropismTropism: the way a plant grows in
response to stimuli in the environment.1) Phototropism: growth response to light
Plants bend towards light
2) Gravitrophism: growth response to gravity plant roots grow down with gravity, shoots (stems) grow
up against gravity and out of the soil. Also called geotrophism
3) Thigmotropism: growth response to touch vines grow up around trees, Venus flytrap closes when
leaves are touched
Slide # 23
Gravitropism
What type of tropism is shown in these pictures?
ThigmotropismPhototropism
Phototropism
ThigmotropismGravitropism
Plants in our lives
Fruits and vegetablesCropsWoodmedicineFibers