1.    Describe the process of transpiration in vascular plants.

Transpiration is the procedure by which plants acquire nutrients in the air and lose their own moisture in the process. The leaf tissues is important for this process.

2.   What environmental factors that you tested increased the rate of transpiration? 

The simulation of time being pass by an hour without the heater, fan, or lamp. 

3.  Was the rate of transpiration increased for all plants tested?

All plants increased their rates of transpiration in the wind environment, and the heat and light environment also helped to increase the rate of transpiration.

4.    Did any of the environmental factors (heat, light, or wind) increase the transpiration rate more than the others? Why?

All plants increased their rates of transpiration in the wind environment.  The wind is blowing the moisture away at a higher rate than if the plant was just sitting in the sun, causing it to transpire more. Transpiration occurs at higher levels with heat because of evaporation.

5.   Which species of plants that you tested had the highest transpiration rates? Why do you think different species of plants transpire at different rates?

Rubber plants. I think it is because plants originally from sub-tropical or tropical areas will transpire at a higher rate than those originally from arid or semi-arid areas. 

6.    Suppose you coated the leaves of a plant with petroleum jelly. How would the plant's rate of transpiration be affected?

They would die because the stomata would no longer be able to open to the outside world, and respiration would be impossible.

7.    Of what value to a plant is the ability to lose water through transpiration?


Because water has cohesion between molecules it is drawn up through the xylem when the water evaporates from the top of the column. This creates the transpiration flow through the xylem and carries any dissolved nutrients upwards with the water. 

Having the ability to draw water and nutrients upwards to a branching leaf canopy allows plants to spread the leaves to intercept more sunlight. 

Transpiration raises the air humidity and moderates the daily change in temperature. 

Evaporation cools the leaves just as sweat evaporating from skin is cooling.

Plant Hormones

Auxin 

Auxin causes plant cell walls to become more flexible, which allows the cells to elongate as they grow. Auxin accumulates on the dark side of a stem. As a result, the cells on the dark side of a stem elongate more than the cells on the light side. The difference in elongation causes the stem to grow toward the light. Auxin also inhibits the growth of the buds along a stem. 

Abscisic Acid

• Induces seeds to synthesize storage proteins.
• Stimulates the closure of stomata (water stress brings about an increase in ABA synthesis). 
• Inhibits shoot growth but will not have as much affect on roots or may even promote growth of roots.  
• Inhibits the affect of gibberellins on stimulating de novo synthesis of a-amylase. 
• Has some effect on induction and maintanance of dormancy. 
• Induces gene transcription especially for proteinase inhibitors in response to wounding which may explain an apparent role in pathogen defense. 

Ethylene 

• Stimulates flower opening. 
• Stimulates fruit ripening.
• Stimulates the release of dormancy. 
• Stimulates shoot and root growth and differentiation (triple response) 
• May have a role in adventitious root formation. 
• Stimulates leaf and fruit abscission. 
• Stimulates Bromiliad flower induction. 
• Induction of femaleness in dioecious flowers. 
• Stimulates flower and leaf senescence.