PLANT TROPISMPLANT TROPISM

ObjectivesObjectives

Identify tropisms in plants.Identify tropisms in plants. Examine effects of tropisms in plants.Examine effects of tropisms in plants. Recall differences in tropisms and effects of Recall differences in tropisms and effects of

tropisms in plants. tropisms in plants.

What is Tropism?What is Tropism?

A A growth movementgrowth movement whose direction is whose direction is determined by the direction from which the determined by the direction from which the stimulus strikes the plant.stimulus strikes the plant.

Negative & Positive TropismsNegative & Positive Tropisms

1. Negative Tropism1. Negative Tropism

2. Positive Tropism2. Positive Tropism

Positive TropismPositive Tropism

Grows in the direction from which the Grows in the direction from which the stimulus originates .stimulus originates .

Negative TropismsNegative Tropisms

Growth away from the stimulus. Growth away from the stimulus.

http://www.cccmkc.edu.hk/~sbj-biology/AL%20BIO/Continuity%20of%20life%20growth%20and%20development/Growth%20and%20development_image/

Tropism_image/Phototropism%20in%20mung%20bean%20seedling.jpg

4 TYPES OF TROPISMS4 TYPES OF TROPISMS

PhototropismPhototropism GeotropismGeotropism HydrotropismHydrotropism ThigmotropismThigmotropism

PHOTOTROPISMPHOTOTROPISM

Response to lightResponse to light

GEOTROPISMGEOTROPISM or or GRAVITROPISMGRAVITROPISM

Response to gravityResponse to gravity

HYDROTROPISMHYDROTROPISM

Response to waterResponse to water

THIGMOTROPISMTHIGMOTROPISM

Response to touchResponse to touch

SummarySummary

What is a tropism?What is a tropism? A growth movement towards a stimulus.A growth movement towards a stimulus.

4 Types of Tropisms4 Types of TropismsPhototropism-growth toward light.Phototropism-growth toward light.Geotropism-growth due to gravity.Geotropism-growth due to gravity.Hydrotropism-growth toward water.Hydrotropism-growth toward water.Thigmotropism -growth due to touch.Thigmotropism -growth due to touch.