Good blogging weather: raining and about 40?F. Laura says it reminds her of winter in Portland, Oregon. Certainly not much like winter in Amherst, Massachusetts.
It was a fairly quiet week in the lab. On the Siamese project, I analyzed files on the computer. Sitting at my desk, opening and closing files, making a few measurements on images, and typing in a few numbers. All part of an experiment but less fun to recount than tales of messing about with seeds and spongy paper.
But I did some of that too. One experiment. I set up two plates of seeds for germination, each the same. In the bottom of the plate, I put 6 Kimwipes, rather than spongy paper, because plates with spongy paper gave both Maura and I nothing but dead seeds, twice. I used the foam doofus, taped around the back, with no top on the plate, allowing the Kimwipe to contact water in the bottom of the box that holds the plates upright. I put this in the 25?C red room on Monday.
When I checked on Thursday, there was good news and bad. The bad was that some seeds had fallen into the water. I suppose that 6 Kimwipes are thinner than the spongy paper and not enough pressure was applied. But it is also possible that the doofuses are loosing their grip. I think I will go back to making the doofus with a wet brown towel. After all, this will keep the kernels wet and can be made fresh every time.
The good news was that each plate was similar. No evidence of the poltergeist. I set up an experiment with the seedlings on an agar plate and held them up by means of a narrow strip of wetted, brown towel placed over the roots (not over the tips). The results were consistent with good days in the past, meaning that the growth rate increased for about 6 hours and then stabilized. Probably, 25?C is a reasonable temperature for maize roots. And holding the roots onto the agar with wet towel is acceptable.
Nevertheless, all is not entirely well in rootland. The narrow towel strip covered one of the root tips by 1 mm or so and that root grew slowly before reaching the edge of the towel and freedom. More seriously, several of the root tips lifted up, off of the agar, even though their upper regions (their shanks, if you will) were snuggled onto the agar surface by the towel. The towel edge was about 1 cm, give or take, from the root tips, and even so, in that free centimeter of root, bends persisted. At the end of the experiment, several of the root tips were well off the agar, meaning that they don’t need to be touching the agar for growth.
When I planned this whole set up originally, I was thinking in terms of roots being covered by the towel including the tips, thereby ensuring contact between the root tip and the agar. I need this because in the actual experiments that I will do, some day (!), there will be inhibitors in the agar and I need reliable transfer of inhibitor to growing tip. For this recent experiment, I had been hoping that putting a towel strip close to, but not over, the tip would be sufficient. But evidently not. Even if I could get the towel edge to within a millimeter of the edge (assume some kind of bionic enhancement of fingers and vision for the dim red light, which is not bright enough to read by), since the uncovered roots can lift up off the agar, it still wouldn’t really solve the problem.
At this point, I am driven to try burying the roots inside the agar (Fig. 1). To do this, I cut a strip of Plexiglas, as long as the plate and about 1 inch wide. I will stand this up in the plate, about one inch from the top edge. This will make a large and a small area on the plate. I will then melt agar medium and pour it into the large area of the plate. When the agar sets, I will remove the strip of Plexiglas, leaving the small area empty, free of agar. When the plate is upright, that edge will become a shelf. For an experiment, I will poke a root through the shelf all the way up to the kernel.
In theory, this will keep the roots surrounded by agar, and they will grow well. In practice? Well we’ll see, won’t we…