Unfortunately, last week started off with all of the seed-born carrot disease experiments having to be redone. The petri dishes we had previously plated were supposed to have easy-to-count bacterial colonies on them… instead, most of the dishes had surfaces that were completely coated with bacteria that wasn’t the kind we were looking for. This means that something got contaminated in the process of the experiment.
For each treatment, we plated 9 different dilutions: 0 through 8. The 0 trials were the control plates and these did not have any of the phosphate buffer used for dilutions added to them. The other trials all had varying degrees of the buffer added. Because the 0 trial petri dishes did not have nearly as much of a coating of the other bacteria (thought to possibly be xanthomonas), it appeared that one of the main culprits of this problem was the buffer!
Sadly, we had to throw all of the previous work away… 
But I got to wear these super cool safety glasses again while redoing the experiments, so everything turned out alright.
One of the other projects we worked on last week was quantifying numbers of infected carrots at soft-rot carrot plots. We went out to two different plots one morning.
These particular carrot fields were pretty badly affected by the soft rot, the female plants more so than the males.
The affected plants can be identified by wilting flowers, black-ish spots near the base of the plant, and overall brown, unhealthiness that continues up to the top rather than only being located around the base of the plant (which is more likely caused by herbicide).
The carrot, or whatever is left of it, in the affected plants is usually very sad looking. The bacteria eats it away, leaving varying amounts of mushy carrot remnants. The amount remaining depends on how long the plant has been infected.
We went up and down the rows, counting how many affected carrots were in each one.
One last project that was started was planting different mustard seeds. These spicy mustard seeds produce an antimicrobial compound that can be used to prevent unwanted bacteria from growing in soil. After they’re done growing, we will be able to see how well their soil resists bacterial growth.
