Hi Deena,
Very interesting project, that. How did your students measure 'density' of chloroplast layers?
Your question about the usefulness of chromatography as a method to identify plants is good because one goal of science is to find new applications for research. I have knowledge of botany and identifying species of trees, shrubs and plants in the field does require study in how to use ID keys. There is an especially useful app for smart phones called Leaf Snap. All you have to do is take a photo of the leaf and the software will compare it to the database of images and tell you immediately what the plant might be. The program then presents you with a set of images of the flowers, seeds, pods, bark and other features that you then use to identify the exact species.
The problem I see with chromatography is how would it be adapted to use for field identification? Chromatography procedures I am familiar with require a lot of chemical manipulation, some way of separating the compounds and a detector to analyze them. It would be a pretty tall order to put all that apparatus into a meter that could be used out in the woods.
Of course, the botanist or forestry person could tag the leaves and bring them back to the lab for analysis and identification. Nowadays, however, with the relative cheapness and accessibility of DNA sequencing, identifying species through DNA fingerprinting has become the norm for characterizing all organisms from bacteria to humans.
The uniqueness of chloroplast layers could be an important feature in plant research. Maybe it would give us some clues about how to create an artificial light-gathering system based on chlorophyll that could be used to make an organic solar cell to produce electricity and oxygen:
http://www.caltech.edu/news/one-step-cl ... uels-45875
That would be a very useful thing to have on the projected manned mission to Mars.
I hope this information is helpful to you. Please post again if you have more questions.
Sybee