Well this is fine mess. If you have been following along then you will know that for my latest plans, I wanted to work with the long-ish roots that result from 3 days of germination. Alarmingly, during the past week, on day three, the roots were short-ish. I tried this twice and both times the roots were too short. Actually, this was going on for a while because, several times previously, the roots were shorter than I expected;  on those occasions, I made do. Then, long-ish roots were not at issue; this week they were. And it was weird. Why are the roots long in some three-day germination runs and short in others?

My immediate thought was too little water. As I have been making up the plates for germination, I have been removing excess water to prevent a puddle at the bottom of the plate; the puddle soaks the permeable tape holding the top and bottom of the plate together and water leaks out. Maybe the spongy paper got too dry? OK, I can solve this one. I put the spongy paper in the bottom plate, as usual, put the row of seeds across, added a foam doofus and simply taped the doofus directly to the back of the plate. I put the plate, nearly vertical as usual, in the large black plastic box and added half an inch of water. In this way, the spongy paper was in permanent contact with water during the three days of germination, thus saturated. The box has a lid so the amount of evaporation is minimal.

And after three days the roots were short. Decisively short. Plenty of water. Well, codswallop. Good that I can rule out a water shortage. But what else? The next thing I thought of was temperature. I have not been monitoring temperature in the experimental room. Whenever I am in the room, the temperature seems “reasonable”. It never feels unusually cold or warm, as it does sometimes in my lab or office. The room has good airflow from a duct. But maybe it gets cold during the night, when I am never there? If this happened on some nights and not others it might explain the slow growth for some but not all experiments. And was is the temperature, anyway? Well, I can find out. I resurrected a temperature logger. This is a little sensor, about the size of a Mars bar. It has a USB plug on the end and it takes instructions from a computer (how often to record the temperature, e.h.g.o.) and once set up, the logger is removed from the computer and put anywhere to patiently record its temperature, in this case every five minutes.

Good. I learned that during the last experiment, where the roots were too small, the temperature held steady, around 22.5?C. This is on the cool side for maize but it seems unlikely to explain just how slow the roots have been growing. I was looking for a swing down into the teens. Now it is possible that there have been swings upward, reaching 26 or 27?C when there were nice long roots. But I doubt it.

What else could be slowing down the roots?

The short answer is: I don’t know. The long answer is: I have an idea. Maybe they don’t like being squeezed? The doofus squeezes the kernels and thus will squeeze the emerging seedling. In the end, shoots and roots will cope but pressure might slow them down while acclimation steps are taken? Squeezy queasy? OK this idea is perhaps farfetched but it is straightforward to test. On Friday, I set up seeds without a doofus or any other squeezing thing. To hold up the seeds, on one plate, I stuck ‘em down on double-sided tape and ran a paper towel right up to the bottom of the kernels. This held the seeds just fine but I am a little worried about whether the kernels will stay hydrated from wet paper touching them at one side only. So on another plate, I used spongy paper and made a shelf where the kernels rested. Wet paper ran underneath them so no problem about hydration but they did tend to tumble off the shelf. Again, the plates had no tops and there was water in the box to keep all the paper wet.

Tomorrow, Monday, it will be three days and I will find out whether these roots are reasonably long. The temperature logger is dutifully keeping track in case the building HVAC goes haywire or whatever.