Spore Sedimentation

Background

A spore falls or is forcefully "pushed" from the stalk which it is connected to.  Though a spore does not

seem to travel a great distance (only a couple millimeters), it is actually quite impressive relative to the

size of a spore (~1250 Âµm³).

So far the average distance the spores travel is 500µm, while the average length of a spore is only

26.2µm. Therefore the spores are travelling on average over 19 times their length!

Procedure

The following is our current method:

• Sterilize a scalpel and forceps
• With forceps, place glass coverslips in an empty Petri dish
• Place two glass slides (directly on top of each other) on top of the coverslips so that half of the coverslips stick out from under the slides

• Cut a block of V8 agar in half with scalpel
• Remove one half of agar from the Petri dish and place in the other dish (directly on top of the glass slids) with metal spatula
• Swab the side of the agar perpendicular to the bottom of the dish with M. oryzae
• Wait 8 to 10 days for fungus to grow and spores to sediment
• Measure distance using NIS Elements program

• The next step:

  Controlling for Convection

Photo of the Assay

7/2/2007

Disecting microscope, 6.3x magnification

Notes about the photo:

• The agar block is the black area on the left
• The red line indicates the edge of the agar block.  The computer program we use printed this line using intensity measurements of the color of the agar under the microscope.
• The green lines measure the length from the agar to the spores.
• The units are µm.
• The photo was taken 10 days after the assay was constructed.

Data

The Mathematics of Spore Dispersal

Spore Dispersal Math 

• The next step:

  Detecting the Mechanism