The Plant Physiological System:
How it works
This experiment was set up at the Headlands Center for the Arts in Sausalito California, in the summer 2008.
We have a range of equipment in two systems that are running concurrently. One system is measuring real-time atmosphere: the quality of the air outside. Another system is running through a plexiglass case that is the leaf chamber. We compare air outside to air in relationship to the leaf itself, because the leaf consumes CO2 and releases moisture through a process of transpiration.
A gas controller measures how fast the air is moving through the system. We have a CO2 analyser which samples the leaf in the leaf chamber. We also have a reference CO2 analyser which samples the atmosphere—the air outside. We have two lab-pro units which are taking data in from our CO2 analysers. Outside on the bar we have light sensors, humidity sensors, and temperature sensors.
The Diagram of the System
The first thing we do in testing a leaf is to turn everything on and get the system set up: get the hardware plugged into the computer and then open the program. With this set up, we are checking the calibration and making sure everything is running as expected, and we are saving the file.
I am looking for a leaf that we can run a test on easily. I am now going to turn on the collection system before I put the leaf in the chamber so that we can see the reaction of the leaf being put in the chamber.
Now the leaf is in the chamber and we are collecting data. At this point the tree is not really conducting any photosynthesis, nor is it transpiring. I just adjusted the flow rate up.
The leaf Chamber
The system is all organised through a laptop computer and here you can see the CO2 concentration. The red is the CO2 concentration outside; the blue is the CO2 concentration in the leaf chamber.
The system is all organised through a laptop computer
Here we are looking at CO2 concentrations and relative humidity. The blue is always the condition in the leaf chamber; the red is the actual condition in the atmosphere.
What is going on the leaf?
A leaf is surrounded by atmospheric turbulence. There are thousands of small pores called stomata under the leaf. Carbon dioxide enters from stomata. The stomata also control the transpiration. The water is drawn from the soil through the root and up the stem. The water passes to the green leaves. Transpiration maintains the leaf temperature and prevents dehydration from the plants. The colour of green in plants consists of chlorophyll. Chlorophyll has the power to capture the sun light, harnessing it to provide energy. The sun light, carbon dioxide, water and chlorophyll create a type of sugar that builds the plant body, fruits and seeds. Oxygen, very important substance for all living things, is a by-product of this process called photosynthesis.
We can not live without plants.
