ISHS Acta Horticulturae 162: Symposium on CO2 Enrichment
DIFFERING PHOTOSYNTHETIC RESPONSES OF C3 PLANT GROWN AT SIMILAR LIGHT INTENSITIES AND CO2 CONCENTRATIONS. |
| Author: | James E. Pallas Jr |
| Abstract:
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. | |
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