Algal Pigments

Algal Pigments

All photosynthesizing plants have certain pigments in them by which

they capture sunlight. All plants have in common the photosynthetic

pigment of chlorophyll, but the other accessory pigments as different.

These accessory pigments can be the same between two red algae, or two

green algae. In this lab a red, green and brown algae will be used to

extract the photosynthetic pigments from. We will also be extracting

the photosynthetic pigments from Coleus sp., which is a red land plant

leaf and, and compare the accessory pigments of this to the red algae.

Methods and Materials

We used two different kinds of red algae for this experiment. The

first was Polysiphonia sp. and the second Porphyra sp. The green algae

were Entreromorpha linza, and the brown algae were Fucus gardneri. The

test plant we used to compare against the red algae was Coleus sp.

A different procedure was conducted for extracting pigments from the

different colors of algae. The red algae were grinded using both water

and 90% acetone in order to get all the pigments out. The green algae

was crushed in 90% acetone only, and the brown algae was placed in

DMSO and then in 90% acetone. We used the same technique for Coleus

sp. was as we did for the red algae.

A spectrophotometric analysis was taken of each of the seven total

samples.

Polysiphonia sp. was not used in the spectrophotometric analysis

because it did not seem to work as well as the Porphyra sp. when we

were extracting the pigments.

Results

The attached graphs show the spectropotometric analysis of each sample

taken. These graphs have the peaks labeled with their corresponding

photosynthetic pigments. Below is a list of the species, and the

wavelength peaks they had.

Species

Wavelengths

Porphyra in water

418 nm, 436 nm, 496 nm, 562 nm, 620 nm, 680 nm

Porphyra in acetone

414 nm, 432 nm, 480 nm, 620 nm, 664 nm

Enteromorpha in acetone

434 nm, 458 nm, 664 nm, 656 nm