Germ Tubes

Our first experiment involves examining the behavior of germ tubes in the presence of volatiles.

Plants give off volatiles as gases, but we will use the volatiles in liquid form for this project because

it is more convenient.  Since the effectiveness of the volatile in gas and liquid form may differ, we are

in the process of testing each volatile in its liquid form on barley, rice, and lima bean leaves.

So far we have tested the following volatiles:

• Limonene - a known volatile of rice
• Farnesyl Acetate - a volatile that contributes to the bean rust fungus

Our plans include headspace sampling (in Harsh's lab) that may help us find more volatiles.

Our ultimate goal is to examine the distribution of orientations that the spores' germ tubes exhibit

in the presence of each volatile.

Photos

Germ Tube Assay Photos

Concentration Gradient

Concentration Gradient

Data

This photo is germinating spores on water agar in the presence of limonene (seen to the left).

(Click to enlarge)

Here is some data we obtained from the above photo.

- Angles between 0 and 180 degrees are pointing away from the volatile.

- The closer to 270 degrees the angle is, the more the spore is oriented towards the volatile.