2018 ASHS Annual Conference

Characterizing the regulation of development by temperature requires controlled exposure of replicate plants (whole or in part) to multiple temperature environments simultaneously. Inexpensive access to the number of environmental chambers needed for the parameterizing temperature response curves for development is not common and can limit the scope of experiments. Similarly, these experiments are often also not included in teaching labs to demonstrate the effects of temperature on plant development. We found an inexpensive (<$40) temperature controller designed for use by homebrewers which allows a chest freezer to be tightly regulated to a desired set point across a range biologically relevant temperatures. Set up can be completed in a few minutes. We included a desktop fan for circulation and water ballast to stabilize temperature responses to opening the lid for observations. Temperature data loggers within the chambers recorded standard deviations of approximately 0.25 °C around temperature set points from 3 to 20 degrees °C. To demonstrate the potential of the chambers we performed two different experiments. First, we used these chambers evaluate temperature effects on ‘time to event’ data for different stages of germination as a laboratory exercise in an undergraduate plant physiology course. Second, we warm forced buds of a woody perennial (peach) at multiple temperatures for the calculation of base temperature and growing degree hour requirement for bud break. For our applications we added flexible strip LED lighting for photoperiod signaling. However, use of the chambers for photosynthetically driven growth may be limited by the lack of CO₂ or humidity control. Measures must also be taken to limit fungal growth due to high humidity.