What is Lemna sp?

Please find out a little about about Lemna sp..
Some teachers are not aware the significance of this species in Bio SPM syllabus.

When you talk about Lemna sp..the aquatic green small plant which is found growing in the pond..it is often used in studies related to abiotic factors affecting its population distribution / GROWTH..Common name for Lemna sp is duckweed.

For example:

Design an experiment to study the effect of pH on the population growth of Lemna sp OR
...Other factors which possibly be asked are: temperature, light intensity, humidity and topography...
..But in the Lab, the factors such as light intensity, pH and temperature could be investigated easier.

Sample QS:
To investigate the effect of light intensity on the population growth rate of Lemna sp

Tips:
1. Identify all the three Variables first!!
Manipulated Var : Light intensities
(How are you going to operate this??...perhaps by using different power of the bulbs : 20W, 40W, 60W and 80W???)

Responding Var: Number of Lemna sp. ((Because Lemna leaves/plants can be counted one by one!!!..its small leaves are cute!)
(The more the number of Lemna means the more growth..)

..and of course the Fixed variable...any suitable parameters such as, pH of water..or even temperature.

...As for pH factors...how to operate manipulated variable?? By using different pH medium of Knop Solution: maybe pH 2, pH6, pH8...and Lemna best growth in neutral medium..Both acidic and alkali are not suitable for Lemna sp.

...As for temperature..manipulate the temperature by using different temperature of water where Lemna is growing..Maybe at 10, 20, 40,60..degree Celcius..

So guys..go and read about Lemna sp..Who knows it might come out for your Paper 3 SPM, Question 1 or even Question 2...