The latest updates are in. Between last week and this week, plants grown in 0% D2O, 30% D2O, 70% D2O, and 80% D2O have died. While this is expected for the larger concentrations, I can’t explain why the 0% D2O sample or 30% D2O sample has died. But I did just think of an interesting effect:

Because the plants are more-or-less sealed from the environment, I have minimized the effects of evaporation and transpiration. I’m not sure if transpired water is harmful to the plants because it basically is their excrement. Regardless, the water in the solid media (the agar) should have a slight rise in D2O concentration due to transpiration processes in the leaves and evaporation of water from the solid media. I’ll have to find the reference for a paper I have that verifies this.