I’m now four weeks into my rhizotron experiments. Neither experiment is progressing fully according to plan (but in biological research nothing ever goes according to plan, so this was not a surprise). I am considering a modification to my flooding experiment, changing the focus from flooding tolerance to post flooding recovery.
The non-flooded plants all look good.
When flooding is added to the equation the Fraser firs look worse than the Nordmann firs at the above ground level. This is what I expected to see.
Things get troubling below ground. I had hoped the Nordmann fir roots would appear different than the Fraser fir roots. Alas, they look the same.
I have seen glimmers of adaptations in the Nordmann firs, but not anything dramatic. I am very curious how far gone the plants are right now. I fully believe the flooded Fraser firs are dead. I suspect the flooded Nordmann firs might rebound if the flooding stopped. And that is what I might test.
The phytophthora root rot experiment in the junior rhizotrons has not provided clear results yet. I think the stress level is not high enough for the disease to cause fatalities. It is not an ideal time (seasonally and physiologically) to cause death in firs due to root rot. This might prove problematic.