Root Washing

In the plus column, I have washed 35 samples of roots. I'm over halfway finished washing the roots from the bioassay! It has been quite interesting to see the variety of masses and volumes of the root systems. When looking at a plant, it is very easy to focus on the quality and size of the above ground mass. I have learned that the appearance of the shoots can be very similar, but the root systems of the plants can look completely different. Furthermore, their volumes may look very similar, but they may have a huge variance in masses. By huge, I mean a couple grams. This is quite a bit when the average mass of the roots remaining after the cassette's subsample is made is only 1.5 grams.

On the other hand, we are far from being finished with these roots! There are 25 samples left to wash. The remainder roots from the washed samples are still in the drying oven along with all of the shoots. Once all of the samples have been washed and dried, we will be able to draw conclusions about their composition. It has been pretty hectic for me, both in and out of the lab, so hopefully by the next post, I will have more of an update. In the words of the Dalai Lama, remember, " The roots of all goodness lie in the soil of appreciation for goodness". Washing these roots has given me a much greater appreciation  for the less obvious aspects of growing; all of the unseen parts are still a part of the big picture. 

Harvesting

On Wednesday,  October 2nd, we harvested the Zea mays bioassay that had been growing in the conetainers for 5 weeks. The 59 samples that survived were around a foot and a half tall and healthy, so we knew that the root systems were pretty strong. We were a little bit sad for our experiment to be leaving the Ecodome, but it will be moving on to bigger and better things!

RIP Zea mays bioassay August 29-October 2

The first step was to separate the roots and shoots of the sample. We harvested the plants by putting the shoots in paper bags to dry in the drying oven and then placed the roots in freezer bags in the freezer to wait until it is their turn to be washed. 

The latest task has been to wash all of the roots for staining and mounting on slides for us to examine. Today, while the Environmental Institute was empty and quiet with everyone on fall break, I made the polyvinyl alcohol-lactic acid-glycerol (PVLG) that we will be using to mount and preserve all of the roots so that they can be stored for around 20 years.  We will view these slides under a microscope and quantify the amount of mycorrhizae present in the roots, using a system that Dr. Chaudhary taught me and I practiced over the summer. 

Getting the roots washed and sorted for slide placement has been one of the more time-consuming processes that I have had to do with this project, which is ironic because the slides are the smallest-scale aspect of the project. For starters, we have 60 samples that need to have their roots washed and freed from the soil, detritus, and rocks that they grew into. This involves several transfers.  Below is a root sample after 2 washes, note the brown specks of soil that are still in the water.

Samples are then laid out and cut into 1 to 2 inch sections to ensure that we are getting an accurate representation of the roots included in each slide. Using forceps, I then take samples from each section of the sample to go into the root cassettes for the time being. Once the PVLG is ready and I have finished washing all the samples and they are cleaned up a bit, we will be able to mount them onto the slides.

As one can see, the root cassettes don't end up holding a large amount of roots, but the rest of the roots are not wasted. We have been recording their freshly harvested mass and then putting them in the drying oven with their shoots, so that we will be able to measure their organic carbon mass once they have dried. 

This process of washing and slide preparation will probably take a couple weeks for me to complete, but hopefully I will be able to post some graphs and other aspects of our project. I am about to begin delving deeper into the evolution of mycorrhizal fungi to supplement the current research. If you see me  and I have soil under my nails in the next couple of weeks, I apologize, but according to Anglo-Saxon law, "Whatever is affixed to the soil, belongs to the soil". Keep letting your roots spread deep, readers!