UOE/2017/033/NT

The department of Geography conducts research into the responses of plant photosynthesis and stomatal conductance responses to changes in climate. The most important photosynthetic parameters, and thus the ones we need to understand, are the maximum rates of carboxylation (Vcmax) and electron transport (Jmax).

To measure Vcmax and Jmax, accurate estimates of mesophyll conductance (gm) are required. Until very recently, gm could not be measured accurately in the field and we were forced to use estimates that are known to be inadequate for water-stressed ecosystems.

Accurate measurements of gm are the key that will advance our knowledge of competing photosynthetic survival strategies of trees to changes in climate, such as drought stress. We wish to purchase a new LI-COR, Li-6800 infra-red gas analyser.

We require this analyser to measure leaf gas exchange and chlorophyll fluorescence together over a larger leaf area of 9 cm2. We require a measurement accuracy of 0.1 µmol mol-1 for CO2 and 0.01 µmol mol-1 for H2O and a fluorometer which allows full control of irradiance and the light in the red-blue spectral blend.

For temperature response measurements we also require this machine to reach stable chamber temperatures 10⁰C above and below ambient temperatures. It is believed that this is the only instrument currently available on the market capable of fulfilling our requirements.

This capability assessment offers alternative bidders the opportunity to demonstrate the suitability of their products to fulfil our needs. Registration is free of charge to potential suppliers.