This post is part of the series Simulating Climates in Growth Chambers.

In some cases, quick and relatively uniform germination is desirable even in the coldest treatment, to reduce noise among populations. In our case, a minimum plant size was also needed for the plants in the coldest treatment to allow for the harvest of fresh green material, at the beginning of the second season, for DNA extraction without impacting growth or phenology. This required starting out with a uniform ‘greenhouse’ regime, which gradually diverged and morphed into climates of 2, 6 and 10 °C MAT. The second season started with the ‘real’ target climates of MAT 1, 6 and 11°C.

Modification of germination temperatures to speed up germination, achieve necessary plant sizes and reduce noise. On the left: the first 14 weeks gradually evolve from a ‘greenhouse’ regime to a real MAT 6°C regime. Right: the last ten weeks are unmodified.

Gradual diversification of temperature regimes in the first season