Measuring the diurnal rhythms of photosynthesis

Like most organisms, plants have an internal clock that regulates processes on a 24 hour schedule. This includes processes connected to photosynthesis, such as diurnal CO2 uptake, stomatal conductance, chlorophyll fluorescence, protein turnover, and many more. When a plant that has been growing under a regular day-light cycle (for example: 12 h light / 12 h dark) is shifted to continuous day or continuous night, many of its processes will continue to increase and decrease (or oscillate) following a 24 h rhythm. This topic is highly intriguing for several reasons: a) it reveals information about how central processes in plants are regulated, b) it can be wasteful to a degree, because it can temporarily reduce the efficiency of light and water used by the plant for growth. However, currently we are lacking a good overview of how strongly the processes related to photosynthesis are affected by diurnal rhythms. This is especially true of dynamic photosynthesis, for example how strongly the rate of photosynthetic induction is affected by the time of day during the photoperiod. In this project, you will measure how strongly photosynthesis and stomatal conductance, as well as their ability to react to sudden changes in light intensity, change throughout the day.

Used skills

  • Gas exchange measurements
  • Chlorophyll fluorescence
  • Data analysis

Interested in doing a BSc or MSc thesis at HPP? Please contact the HPP student coordinator Katharina Hanika.