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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Adaptive Cropping Systems Laboratory » Research » Publications at this Location » Publication #366766
Research Project: Experimentally Assessing and Modeling the Impact of Climate and Management on the Resiliency of Crop-Weed-Soil Agro-Ecosystems

Location: Adaptive Cropping Systems Laboratory

Title: Variation in responses of photosynthesis and apparent rubisco kinetics to temperature in three soybean cultivars

Author
item BUNCE - Retired ARS Employee

Submitted to: Photosynthesis Research
Publication Type: Research Technical Update
Publication Acceptance Date: 8/23/2019
Publication Date: 10/23/2019
Citation: Bunce 2019. Variation in responses of photosynthesis and apparent rubisco kinetics to temperature in three soybean cultivars. Photosynthesis Research. 8:443.

Interpretive Summary: Recent assays of the responses of Rubisco to temperature in C3 plants have revealed substantial diversity. Three cultivars of soybean, Holt, Fiskeby V, and Spencer, were grown in indoor chambers at 15, 20, and 25 C. Leaf photosynthesis was measured over the range of 15 to 30 C, deliberately avoiding higher temperatures which may cause deactivation of Rubisco, in order to test for differences in temperature responses of photosynthesis, and to investigate the Rubisco kinetic characteristics responsible for any differences observed. The three cultivars differed in the optimum temperature for photosynthesis (from 15 to 30 C) at 400 ppm external CO2 concentration when grown at 15 C, and in the shapes of the response curves when grown at 25 C. The apparent activation energy of the maximum carboxylation rate of Rubisco differed substantially between cultivars at all growth temperatures, as well as changing with growth temperature in two of the cultivars. The activation energy ranged from 58 to 84 kJ per mol, compared with the value of 64 kJ per mol used in many photosynthesis models.

Technical Abstract: Photosynthesis, which drives plant growth, varies widely among species in its response to temperature. However, to date little effort has been made to match the temperature responses of photosynthesis with the temperatures of the environments where crop varieties are grown. This work discovered that three commercial varieties of soybean differ widely in their response of photosynthesis to temperature. The research suggests that better matching of cultivar temperature responses with climate could be a new avenue for crop improvement.