a

Preparation and Anticipation

At the beginning of the internship I had multiple project ideas, to make sure that one would be doable given time constraints and available fresh material, and thankfully one of them tied in perfectly with my mentor’s projects after some adjustments. My mentor, Drake Mullet, hopes to answer the questions, how do nutrients impact the outcome of antagonistic interactions, and how do different antagonistic interactions impact the outcome of another antagonistic interaction (herbivory)? He will observe intraspecific, interspecific, and parasitic interactions to get his answers.

The question I will answer with my project is, how do induced physical defenses differ under different antagonistic interactions? I will be looking specifically at silica hair content on the blades of Koeleria macrantha (prairie Junegrass). These past few weeks have mainly been occupied by reading scientific articles to get a better understanding of silica content as an induced defense, and developing a good method to see and count silica hair on the blades. For now we have decided to use safranin to die our cuts of the blades of grass. We found the most beneficial cut to be a peel-like cut done by cutting into the blade of grass, to get the epidermal layer without chloroplasts, and that layer is then removed by a pulling motion which peels the layer down the blade’s length. We chose this method after practicing different methods on Junegrass that we collected from the garden’s grounds.

SIL.jpg
We collected blades of Junegrass on the grounds, and
from the sandbox next to the Plant Science Center.

From the reading that I’ve done, I feel like I have more questions than notes, especially concerning the roots and how they will react in comparison to the blades in silica production. The parasite we are working with conducts its parasitic interaction with its roots, so will this cause the roots to divert silica production efforts to the roots, will it cause a similar increase in silica both above-ground and underground? Grasses have a greater amount of their silica content in their roots, will the parasitic interaction at the roots cause the silica content to go down in the host’s roots and go up in the parasites roots? Will it increase in the leaves of the parasite? When we were testing what would be the best way to look at the silica hair in the blades safranin was clearly the best clear, but with the roots it was very difficult to tell the silica hairs from the roots. I found papers that were able to completely separate the silica content from the rest of the plant to find a total mass of silica for each plant, if this is something we can replicate at the garden, I believe it will be a better approach to answering my question. This would allow us to compare silica content in a variety of combinations with more accuracy.

SIIL_OIL.jpg
Originally we viewed the section under oil immersion
at x1000 magnification because we anticipated the
​hairs to be more difficult to see than they actually were.

As we enter week four, the pace will start to pick, we will begin to pot up plants this week. Hopefully all will go as planned, and we’ll have our answers.