Fun with Photosynthesis

A Plant is a Living Organism (Dieffenbachia)

A Plant Leaf is made of Cells

  • Two layers of epidermis (skin) cells...not green
  • Two layers of mesophyll (middle of leaf) cells...dark green palisade and light green spongy
  • There are gas spaces between the mesophyll cells (78% nitrogen, 21% oxygen, 1% other is our atmosphere)

A Plant Leaf performs Photosynthesis in Mesophyll Cells

CO2
carbon dioxide 		+ H2O
water 		light
-------------->
chlorophyll 		O2
oxygen 		+
  		CH2O
carbohydrate

Basic Procedure

  1. Punch leaf discs into 20 mL syringe body
  2. Fill with carbon dioxide water (1 tsp baking soda in 1 liter of water)
  3. Vacuum out gas spaces, swirl to fill with carbon dioxide water, to sink discs
  4. Place within a few inches of fluorescent bulb, watch discs float

Having Fun with Photosynthesis:

  1. Do plants really need light? (one in light, one in dark--film can over top)
  2. Do plants really need chlorophyll? (green discs in one, white discs in other)
  3. Do plants really need carbon dioxide (carbon dioxide water in one, plain water in other)
  4. Do plants really produce oxygen? (float discs in two in light, then put one in dark)

Extension Thinking

  1. Plants remove carbon dioxide from atmosphere--help prevent global warming
  2. Plants need to be watered--can help drain wet areas
  3. Plants provide shade by absorbing light--free air conditioner for your house
  4. Plants produce oxygen for us to breathe
  5. Plants produce carbohydrates for our food, clothes, medicines, fossil fuels, etc.

Ross Koning, Biology Department, Eastern Connecticut State University, Willimantic, CT 06226

koning@easternct.edu -- (860)-465-5327 -- http://plantphys.info