Phototropism

Important Notes to Know:

• The word photo in phototropism revers to light and tropism as in  growth response, so phototropism means light growth response. 
• positive phototropism means growth towards the light.
• wherever the light hits on the plant the compound called auxin moves in the opposite direction. 
• Auxin is a plant hormone.  
• Auxin causes plant growth this causes plants to bend towards light. 

Geotropism

Important Notes to Know:

• Geo in the word geotropic revers to gravity and tropic as in growth response so geotropic means gravitational growth response. 
• Roots growing down a seed is called positive geotropism.
• Embryonic shoot of a plant growing up towards the soil is called negative geotropism.
• If the germinating seed is rotated the roots will still grow downwards because of geotropism. 
• If the germinating seed is rotated the Embryonic shoot will grow upwards because of geotropism.  

Plants and Stimuli

Important Notes to Know

• Stimuli are changes in the environment 
• Receptors detect stimuli and turn them into a response
• The responses often take the form of growth.
• The growth response is called a tropism
• the connection between the receptor and the response usually takes the form of plant hormones called plant growth regulators such as Auxin. 

Transpiration

Important Notes to Know

• Transpiration is the evaporation of water from the surface of a plant.
• The equation for transpiration is H20+Sunlight----> Gas
• Phase change from liquid to gas occurs in the space just above the stomatal pore
• Diffusion of water vapor happens through the stomatal pore.
• Sunlight warms the leaf in order of evaporation to occur.
• Sunlight is absorbed by the leaf which emits heat and that causes the phase change to water vapor.

How to use a Potometer

Image From: en.wikipedia.org/wiki/Potometer#use

How to Setup 

1. Cut a leafy shoot from a plant and plunge its base into water. This prevents the xylem from taking up any air. Wetting the leaves themselves will alter the rate of transpiration.
2. put the whole of the potometer into the sink. Move it about until all the air bubbles come out.
3. cut the shoot's stem underwater. Put it into the bung.
4. Make sure the tap is closed, then lift the whole apparatus out of the water.
5. Leave the end of the capillary tube out of the water until an air bubble forms then put the end into a beaker of water.

How to use 

1. Set up the conditions of the experiment. changes to lighting (placing the plant in bright light or shadow), wind (directing a fan at the plant), and humidity (placing the plant in a humid chamber) are normal.
2. Let the bubble reach a "zero" point in the tube. 
3. Measure the movement of the bubble at regular intervals and record the results in excel or on paper.

Structure of a Root

Image from: media.web.britannica.com/eb-media/05/5605-004-CFE4B012.gif&imgrefurl=http://www.britannica.com/EBchecked/topic-art/138864/382/Cross-section-of-a-typical-root-showing-the-primary-xylem&h=320&w=458&sz=37&tbnid=D1sEhcmQ7jYteM:&tbnh=89&tbnw=128&prev=/images%3Fq%3Dstructure%2Bof%2Ba%2Broot&zoom=1&q=structure+of+a+root&hl=en&usg=__FlX1J74XewoVXldlQ9RMilmOTzs%3D&sa=X&ei=LyJ8Ta7IJfOD0QGY-fzLAw&ved=0CB4Q9QEwAw

The Uptake of Water

Important Notes to Know:

• The roots branching pattern is to increase the surface area to increase water intake.
• The roots will branch out to find a water source. 
• The root hairs on the roots are epidermal cells where the cell wall has been extended. 
• Root hairs increase the surface area for the absorption of water. 
• Plant concentrates minerals in the root hairs so the plant can take up water. 
• Water is taken in by the roots by using osmosis. 
• In osmosis the water moves from a dilute region to a highly concentrated region.