Bubbling Cabomba Pondweed: Teaching Notes
Bubbling Cabomba pondweed Teaching Notes
Introduction
Like many other water plants, Cabomba has specialised tissue called aerenchyma that allows gases to diffuse inside the plant. Aerenchyma provide buoyancy and allows oxygen transport to the submerged roots that may otherwise be in hypoxic (low oxygen) conditions. If you cut through the aerenchyma, oxygen can escape.
This can be made use of this in the classroom to show how the rate of photosynthesis is affected by light intensity or by the colour of light reaching the plant. Don’t worry if you have tried to do his with other pondweed in the past - Cabomba is very reliable and bubbles freely for hours.
This document will explain how students can investigate the rate of photosynthesis by monitoring oxygen generation in Cabomba. It includes notes on how to do this by:
1) Counting Cabomba bubbles in white light
2) Counting Cabomba bubbles in different wavelengths (colours) of light
3) Collecting Cabomba bubbles in a pipette
4) Collecting Cabomba bubbles in a microsyringe
Demo video
We have produced a demo video showing how to get the most out of this protocol in the lab, available at https://www.youtube.com/watch?v=eIEJ0FfB-VI
Safety and biosecurity
Take care with use of water near electrical equipment. Ensure hands are dry when using lamps
Keep all containers of water away from sockets and from areas where spills could drip into sockets. Boiling tube racks could be placed into trays to catch any spills and prevent water running onto electrical equipment.
NB Cabomba is not native to the UK and should be disposed of in domestic rubbish and not put into ponds or waterways.
Apparatus
Per group to set up a piece of bubbling Cabomba
Approx 7cm long piece of Cabomba
Boiling tube
Boiling tube rack (type that allows light to illuminate whole tube)
Lamp (see ‘lighting’ in the technical notes)
Meter ruler / measuring tape
Stop clock
1% sodium hydrogencarbonate solution (using sodium hydrogen
Introduction
Like many other water plants, Cabomba has specialised tissue called aerenchyma that allows gases to diffuse inside the plant. Aerenchyma provide buoyancy and allows oxygen transport to the submerged roots that may otherwise be in hypoxic (low oxygen) conditions. If you cut through the aerenchyma, oxygen can escape.
This can be made use of this in the classroom to show how the rate of photosynthesis is affected by light intensity or by the colour of light reaching the plant. Don’t worry if you have tried to do his with other pondweed in the past - Cabomba is very reliable and bubbles freely for hours.
This document will explain how students can investigate the rate of photosynthesis by monitoring oxygen generation in Cabomba. It includes notes on how to do this by:
1) Counting Cabomba bubbles in white light
2) Counting Cabomba bubbles in different wavelengths (colours) of light
3) Collecting Cabomba bubbles in a pipette
4) Collecting Cabomba bubbles in a microsyringe
Demo video
We have produced a demo video showing how to get the most out of this protocol in the lab, available at https://www.youtube.com/watch?v=eIEJ0FfB-VI
Safety and biosecurity
Take care with use of water near electrical equipment. Ensure hands are dry when using lamps
Keep all containers of water away from sockets and from areas where spills could drip into sockets. Boiling tube racks could be placed into trays to catch any spills and prevent water running onto electrical equipment.
NB Cabomba is not native to the UK and should be disposed of in domestic rubbish and not put into ponds or waterways.
Apparatus
Per group to set up a piece of bubbling Cabomba
Approx 7cm long piece of Cabomba
Boiling tube
Boiling tube rack (type that allows light to illuminate whole tube)
Lamp (see ‘lighting’ in the technical notes)
Meter ruler / measuring tape
Stop clock
1% sodium hydrogencarbonate solution (using sodium hydrogen