DIFFERING PHOTOSYNTHETIC RESPONSES OF C₃ PLANT GROWN AT SIMILAR LIGHT INTENSITIES AND CO₂ CONCENTRATIONS.

Populations of peanut (Arachis hypogaea, L.) and soybean (Glycine max., Merr.) were grown under controlled environmental conditions at 25 °C, 60% RH 14-h photoperiod and 20 °C, 90% RH nyctoperiod.
Two different light sources were compared: fluorescent-incandescent lamps (500 uE m^-2s^-1PAR) and metal halidehigh pressure sodium lamps (500, 1000 and 1500 uE m^-2s^-1 PAR). Light interaction with atmospheric CO₂ concentration (350 and 700 u1 1^-1) during growth were subsequently evaluated in a closed photosynthetic system.
Both high light and high CO₂ concentration during growth of soybean increased its photosynthetic rate and saturation intensity.
Whereas neither high light and/or high CO₂ concentration during growth of peanut effectively changed its photosynthetic rate or saturation intensity.
Peanut leaf photosynthetic rates exceeded soybean photosynthetic rates at all light intensities grown with 350 ul 1^-1 whereas soybean photosynthetic rates only equalled peanut after being grown at 1500 uE m^-2s^-1 and 700 ul 1^-1. An increase in soybean leaf photosynthesis appears to parallel an increase in its leaf conductance when grown under high light.

Symposium on CO2 Enrichment

James E. Pallas Jr

https://doi.org/10.17660/ActaHortic.1984.162.14