Plant pigments- chromatography (1 Viewer)

[tam89]

Hey... i got questions from the lab manual that i'm stuck on. Any help would be great.

1) Referring to Rf values of pigments, what do the Rf values of various pigments tell you about their relative polarity?

2) In my experiment, there were no pigments shown in the dark reaction of photosynthesis. So what does a plant grown in the dark tell you about the synthesis of photosynthetic pigments?

 

[Survivor39]

Hey... i got questions from the lab manual that i'm stuck on. Any help would be great.

1) Referring to Rf values of pigments, what do the Rf values of various pigments tell you about their relative polarity?

Rf value is the ratio of the distance travelled by the solute, in this case plant pigments, to the distance travelled by the solvent. Depending on whether your solvent system is hydrophobic or hydrophilic, the Rf value will mean different things. So, say you've used n-butanbol:acetic acid:water solvent in your experiment, it would be hydrophobic (non-polar), hence the more polar the pigments, the lower the Rf value. If a hydrophilic solvent such as silica is used, then the polar pigments would result in a higher Rf value.

2) In my experiment, there were no pigments shown in the dark reaction of photosynthesis. So what does a plant grown in the dark tell you about the synthesis of photosynthetic pigments?

hmmm.. may be there was no synthesis of photosynthetic pigments present? It is very costly to maintain those pigments and if there is no light interception, then plants would degenerate those pigments.


I hope this helps.