Tag Archives: tobacco seeds

Growth of Arabidopsis in heavy water

Arabidopsis seeds in DI water (0.0156% D2O).
Arabidopsis seeds in DI water (0.0156% D2O).
Arabidopsis seeds in 33% D2O.
Arabidopsis seeds in 33% D2O.
Arabidopsis seeds in 66% D2O.
Arabidopsis seeds in 66% D2O.
Arabidopsis seeds in 99% D2O.
Arabidopsis seeds in 99% D2O.

Growth of tobacco seeds in low concentrations of deuterium

Growth of tobacco seeds in DDW.
Growth of tobacco seeds in DDW (0.0001% D2O).
Growth of tobacco seeds in DI water.
Growth of tobacco seeds in DI water (0.0156% D2O).
Growth of tobacco seeds in 1% D2O.
Growth of tobacco seeds in 1% D2O.
tobacco seed root length
Tobacco seed root length growth.

Growth of Tobacco Seeds in Heavy Water

Growth of tobacco seeds in DI water.
Growth of tobacco seeds in DI water.
Growth of tobacco seeds in DDW.
Growth of tobacco seeds in DDW.
Growth of tobacco seeds in 33% D2O.
Growth of tobacco seeds in 33% D2O.
Growth of tobacco seeds in 66% D2O.
Growth of tobacco seeds in 66% D2O.
Growth of tobacco seeds in 99% D2O.
Growth of tobacco seeds in 99% D2O.

Tobacco Seed Growth Rates

I got some awesome new data to show. The first is the compilation of all the Repeating Crumley experiments. And the second is some new data that I’ve been meaning to create and now have with the help of Koch.

Tobacco seed germination rates
Tobacco seed germination rates

The data above is the compilation of all the RC data. Each trial had different water types, but I combined the samples that were the same in every set (DDW, DI water, 33% D2O, 66% D2O, and 99% D2O). Steve adapted his R-code that applies binomial confidence intervals to a data set and used it on this data. If that makes no sense, then just know that the dotted lines are the most probable range of germination rates. For instance, in 66% D2O there is a ~70% likelihood that seeds will germinate at a rate within the dotted yellow lines.

Now it’s time for some brand new data:

tobacco seed root length
tobacco seed root length

Here we went through the pictures from Trial 5 and compared the growth rates of the roots. We calculated the lengths of various seeds in each image and tracked the changes from image to image. We chose DI, DDW, and 1% D2O, because the D2O concentrations are relatively similar and because we wanted to test a hypothesis from a while ago. It’s interesting that the seeds in DDW and D2O grow at the same rate, while seeds in DI water grow at roughly half the speed.

RCD: Day 36

This will be the final data point for this experiment. Looks like seeds don’t grow in 99% D2O as Lewis reported, but Crumley argued against.

RCD: Day 28

Still nothing growing and the old sample that had one sprout stopped growing as well, which leads me to believe it started growing a long time ago, possibly while still in the package and not in D2O, and I just never noticed.

RCD: Day 22

It should be noted that the annual spring cooling system maintenance is occurring as I post this. That means that the lab is excurciatingly warm right now and this may negatively impact the seed growth (which shouldn’t happen anyways).