This week was off to a busy start as the magnolias finally showed enough root growth to be waterlogged. The trees will be fully submerged for a 14-day period. During that time we will be taking photosynthesis and stem diameter measurements. The maples will take their plunge next Monday and then we will be on double duty! But just because the trees are taking an extended swim doesn’t mean we will be sitting around guarding. We have other important duties to address, such as feeding our hungry caterpillars … and feeding ourselves! Keep reading to find out more about the Root Lab cuisine.
Traced and recorded leaf counts of waterlogging trees
If you can remember back to our first tracing session last month, we used a green paint-marker for the first age class of roots. For the second tracing we used yellow. The magnolias showed a good amount of root growth, with only a couple of the Star magnolia species showing no growth in a single window or two.
Leaf counts were taken using a hand tally counter and the help of Don, an arboretum volunteer. For the magnolias, this was no small feat with most of the trees having 200+ leaves! We will be counting again at the end of the seven-week period to see if the trees dropped their leaves due to the waterlogging stress.
Harvested root samples and began waterlogging the magnolias
Harvesting tissue samples allows scientists in many fields to run an unimaginable range of tests on an unimaginable range of organisms. For our purposes, we will be focusing on roots and shoots.
Below is the procedure we took to harvest roots from a single window of each tree:
Cut open clear window of rhizo-pot
Selected fine roots with tweezers and cut using scissors or scalpel
Cleaned potting mix from roots
Weighed on digital scale
Stored roots in labeled falcon tubes and put in liquid nitrogen
Moved falcon tubes to -80℃ freezer
We will be running stress measurements on these tissue samples once the waterlogging trial is done. Specifically we’ll be looking at lipid-oxidative damage and peroxidase activity. If those words seem daunting, don’t worry, I’ll break down what they mean and what cellular functions they involve in a future blog post. For now it’s just important to know that they will tell us how stressed the roots are. What would you hypothesize about the stress levels in the roots of a tree that is sensitive to waterlogging? What about a tree that’s tolerant?
Recorded stem diameters of magnolias
There are many ways scientists can record stem diameter. One of them is to use a tool called a caliper. A caliper is an instrument that measures the distance between two points and gives you a reading either digitally or on a ruled scale. We want to see if waterlogging changes the trees’ growing patterns, so we are measuring stem diameter throughout the course of the experiment.
Foraged for mushrooms
It’s Chanterelle season, so don’t miss out on the opportunity to forage in a forage-able place near you! Chanterelles fruit anytime from late spring to early fall in mixed hardwood forests. I have been sworn to secrecy so unfortunately I can’t share the location within the arboretum where we tend to find these fun guys (he-he, get it?), but I’ll just tell you that they like Oaks and you can start from there. The species seen below is the Chicago Chanterelle (Cantharellus chicagoensis).
First we foraged, then we feasted! We cooked these up with just a little bit of avocado oil, salt, and pepper.