I am typing this with a Bandaid wrapped around my left index finger. If this text is missing a few t’s, that is why. Last Friday afternoon in the lab, I had an accident with a paper cutter. I was making foil squares for culturing BY2 cells and the sheet of foil is 18 inches wide. Cutting it requires, shall I say, decisive strokes. I respect the power of the paper cutter and I always pay close attention to the location of my fingers, but something went wrong yesterday. Was I distracted? Tired? Old? I don’t know, but I sliced off a little of the pad on the side of my finger. Fortunately, I didn’t lose half the finger. The skin will grow back. I continued cutting the foil squares with a trepidation that will stay with me for the rest of time. Probably not a bad thing.

But now, a for the white towels, they are guilty. Last Monday, unrolling the jelly rolls, I saw, in the one made with the white paper towels, seedlings with short roots. The one made with brown towels had seedlings with long roots. Evidently, something about the white towels is unpleasant for roots.

I transplanted seedlings with long roots onto an agar plate and imaged their growth, exactly as previously. As seen in the figure, by about 5 h after being placed on the plate, the roots grew at a constant rate (the line with the filled in circles, the most recent experiment, becomes horizontal at around hour 5 for the rest of the time course).

OK, that’s nice. But look, even this batch took some hours to get up to speed. Certainly, root growth is closer to ideal constancy but it is not constant. Is there a way to improve things further? I am not chasing perfection for perfection’s sake: for the envisioned experiments, I predict that growth rate will be changed around three hours in, so it would not be a bad thing for the controls to be steady during that time.

What could explain the slower growth at the first part of the experiment? The brown towels might have less of toxic substance X than the white ones but still have a little of it. But also, when I move the seedlings from the jelly roll to the agar plate, they experience a host of changes; the roots go from being possibly oxygen-limited, swaddled in foamy paper, to sitting on the surface of moist agar, and they get shined on by red light. These are things to give any root pause.

To test this, I will try germinating seeds directly on the agar. I have been avoiding this because I thought the seeds would fall down. But I realized that the trick I used to keep seedlings from falling down should work with just seeds. That trick, described here, is to put a moist towel or Kleenex on top of them, with the needed support coming from the large surface of contact between agar and paper. Because I take the pictures through the agar, it doesn’t really matter what is behind the roots.

This way, the seeds will germinate on agar and the roots will see the red light always. The only manipulation needed will be to pick up a seedling from the agar and put it down again. That manipulation is required because, for later experiments, I need to move seedlings onto agar laced with a chemical. If it turns out that even this mechanical perturbation causes the roots to grow slowly for a while afterwards, then I have to live with it. But perhaps by lessening the changes happening to the roots as the experiment starts, I can lessen the period of slower root growth at the beginning? Time will tell.