I am writing this post a bit late today because I indulged my Slitherlink addiction. This is a logic puzzle that I encountered in Japan while looking for something besides Sudoku. The idea is to draw a continuous loop, no intersections, that goes by all of the numbers in the grid in such a way that a 3 has three links around the number occupied, a 2 has two, a 1 has one, and a zero has none. Nice simple rules, deceptively difficult. Lots of fun. There are on line portals, you can get addicted too!

I was eager for this past week’s experiment. I had happily extrapolated from the vigorous germination of the Silver Queen seed to a vigorous response of the coleoptiles to auxin. Nope. On Tuesday, experiment day, the seedlings were indeed beautifully uniform – soldiers on parade. I had as many as I needed of a similar, and convenient size. I cut the segments, allowed them to float for an hour, put them in various concentrations of auxin, including zero, took their photos at once, and again after four hours. From the images, I measured growth rates. And the growth at the best auxin concentration was a lackluster 4% per hour.

That rate is the same as coleoptiles from the UK maize. And both materials give excised coleoptile segments that grow with reasonable uniformity. Now that the UK material has aged, I must sow many more kernels than I need for an experiment, but whatever is limiting germination appears not to be curtailing a response to auxin. OK then.

For completeness, I am going to try Silver Queen mesocotyls. The coleoptiles of the UK material never had the crazy variability of the mesocotyls. The fastest mesocotyl segments hit a growth rate of 10% per hour and even the average was around 6% per hour. The amped up growth is a major reason why I have been pursuing mesocotyls. In this game of turning over stones, checking the genotype for the source of variability seems reasonable. I have the seed and everything in place.

During the past week, I spent plenty of time metabolizing numbers (for an explanation of that unusual phrase, please check the last post) on the computer. Good progress, but I’ll need an entire post to explain. I think I’ll wait until the metabolic reactions consume the last of the substrate.