Modeling of Fungal Colony Growth inside Substrate


by Shu Matsuura, Tokai University, Japan. last update 2000/06/12

This page introduces a simplified model of fungal colonies. Click here to DOWNLOAD JAVA APPLET, in a new window. I'm making this kind of  models to get, possibly, a better understanding on the colony patterning of fungi and mushroom formation (in future) under various basic environmental conditions.
The hyphal colony grows in a 3D square lattice space (50*50*20 lattice unit) with uniformly distributed nutrient. Hyphae are created by consuming nutrient particles that diffuse in the medium space.
(below an image)

image of applet

Sorry!:

Loading and running this Java applet program might eat up more than 11MB of RAM of your computer!
Also, the running time may be terribly long depending upon the choice of simulation variables.

  Usage:

1.      Set gTotal Mycelial Massh with the scroll bar. Please select a small number for the first time.

2.      Set g% of Spawn in the Substrateh. This defines the initial number of eseeds of hyphae (or spores)f that are distributed in random. The number of seed hyphae is defined by the percentage of the mass of substrate, namely, the number of total lattice points 50000 in this model. Actual number of seed hyphae is shown in the text box of "Mycelial Mass" when you push "Spawning" button, described below. There are two sexually compatible hyphal types that are distinguished by color (green and red).

3.      Set gMax No. of Hyphae at Each Siteh. The hyphal units occupy the lattice sites. Each lattice site can be occupied by more than two hyphal units. In the simulation, when two different types of hyphae are created in a site, at least one of them creates secondary hypha that are colored blue.

4.      Set gInitial Nutrient Levelh. This is the initial number of nutrient particles delivered to each site. If you set it less than 5, the running time will bec.forget it!

5.      Set gNutrient Diffusionh. This is actually the length of the trajectory of nutrient random walk. In this model, this number may be regarded as the diffusion coefficient of nutrient particles. If you set it large, it will again enlarge the running time.

6.      Set gHyphal Growth Rateh. The right scroll bar controls the exponent of the hyphal growth rate. The hyphal growth rate is defined by the frequency rate of nutrient uptake to the number of succeeding nutrient random walks.

7.      Then, push gSpawningh. You can see the seed hyphae are distributed in random. The amount of seed hyphae is shown in "Mycelial Mass" text box.

8.      Push gCultivationh. The growth begins. But the colony shape does not appear until the number of hyphae produced reach the gTotal Mycelial Massh you set.

Sometimes push buttons may not work! Try again. The text boxes show the current numbers of mycelial mass, average number of nutrient particles stored at each site, and the number of secondary hyphae generated. But, actually, not all of the boxes report the refreshed data.

Even after the growth, rendering colonies takes time.

Brightness of hyphal color indicates its vertical position. Right picture is the scanned image.

Efficiency of the production of secondary hyphae is of great interest.


I would be so happy if you could give me your comments.

Shu Matsuura
School of High-Technology for Human Welfare, Tokai University,
Nishino 317, Numazu, Shizuoka 410-0395.
fax: +81-559-68-1224
e-mail: shum@wing.ncc.u-tokai.ac.jp


Links:

Introductory Science Education Section, Tokai University, Numazu Campus. (Our web-based education site. Japanese only.)

Everyday Physics on Web. (My web-based introductory physics education site. Japanese only.)