CHARACTERIZATION OF POPULATION CO2 EXCHANGE OF POTATO GROWN IN KSC'S BIOMASS PRODUCTION CHAMBER.

Abstract

To characterize CO2, exchange, potatoes (Solanum tuberosum cv. Norland) were grown for 90 and 105 days in KSC's Biomass Production Chamber, a 116 m-3 closed cuvette, with 0.5 strength modified Hoagland solution using recirculating NFT culture, 12/12 photoperiod, 1000 μmol mol-1 CO2, and approximately 900 μmol m-2 s-1 PPF from HPS lamps. Canopy gas exchange responses to CO, concentration, light intensity, and photoperiod were experimentally determined. CO, exchange showed a linear response to PPF (up to 1100 μmol m-2 s-1 max.) and a light compensation point of about 150 μmol m-2 s-1. Sustained exchange rates of >45 μmol CO2, m-2 s-1 were obtained 50 days after planting. CO2 saturation was approximately 1200 μmol mol-1 CO2 with a compensation point < 100 μmol mol-1. A dark cycle of less than 4 hours resulted in a rapid, continuous decrease in C02 exchange rate which was partially reversed by a 12-hour dark cycle. There was a weak correlation CO2 exchange and leaf starch concentration at the end of the dark cycle.