Investigating photosynthetic and chlorophyll fluorescence responses to light in peanut acclimated to elevated CO2 and temperature

Authors: ADIREDDY, RAJANNA - Oak Ridge Institute For Science And Education (ORISE); Anapalli, Saseendran; Delhom, Christopher; PUPPALA, NAVEEN - New Mexico State University; Reddy, Krishna

Submitted to: Photosynthesis Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2025
Publication Date: 5/14/2025
Citation: Adireddy, .G., Anapalli, S.S., Delhom, C.D., Puppala, N., Reddy, K.N. 2025. Investigating photosynthetic and chlorophyll fluorescence responses to light in peanut acclimated to elevated CO2 and temperature. Photosynthesis Research. Photosynthesis Research (2025) 163:29. https://doi.org/10.1007/s11120-025-01151-8.
DOI: https://doi.org/10.1007/s11120-025-01151-8

Interpretive Summary: The reliance on fossil fuels for energy is causing a rapid rise in greenhouse gases that trap and heat the atmosphere. The primary component of these gases is carbon dioxide, which plants utilize for growing biomass. While higher levels of the gas can enhance crop yields, the accompanying increase in air temperatures due to the heat-trapping nature of these gases can induce heat stress in plants, ultimately reducing biomass production. Therefore, it is crucial to investigate how these conflicting factors will influence crop yields in the future. To address this, researchers from the Crop Production Systems Research Unit and Sustainable Water Management Research Unit, USDA ARS, Stoneville, MS and New Mexico State University, NM have developed and utilized climate-controlled growth chambers in which plants can be grown under simulated future climates. These plants allow us to grow crops to study variations in production and devise strategies to maintain agricultural output in the future. This article presents our findings on how photosynthetic biomass production in peanut plants growing in the climates of 2050 and 2080 respond to light variations across the crop season.

Technical Abstract: In plants, the photo-inhibitory effects of incident lights on the light-harvesting complexes are balanced by photoprotective mechanisms to maintain photosynthesis. With increasing air CO2 concentrations and temperatures, the balance can tilt either way, with unpredictable consequences for biomass assimilated through photosynthesis. As such, it is critical to assess the photosynthetic responses of crop plants growing in future climates to light for developing strategies for sustaining food production. This study evaluated changes in photosynthetic and chlorophyll fluorescence responses to light intensities in peanuts (Arachis hypogaea L) acclimated to projected future climates by Global Circulation Models (GCM). The plants were grown in plant growth chambers under three climate conditions (CC): (1) ambient air [CO2] and ambient temperature [Ta] (CC1), (2) [CO2] at 570 ppm and Ta + 3° C (CC2 climate possible in 2050), and (3) [CO2] at 780 ppm and Ta + 5°C (CC3, climate possible in 2080). Plants growing under all three climates enhanced photosynthetic rates (A) with light intensities from 0 to 1500 µ mol m-2 s-1 but decreased afterward. Compared to CC1, plants growing under CC2 and CC3 reduced electron transport rates (ETR), A, and transpiration (Tr) between 48 and 190%, 52 and 65%, and 22 and 24%, respectively. Concurrently, the quantum efficiency of photosystem II ('PS2) was reduced by 88-200% and photochemical quenching (qP) by 55-170%. Non-photochemical quenching increased with increasing light levels from 200-1500 µmol m'² s'¹ and decreased afterward. Results indicated the possibility of reduced photosynthetic efficiencies under CC2 and CC3, which would significantly reduce biomass production in future climates. Gaining insight into these impacts can help understand plant's ability to adapt and assist in developing adaptive strategies for sustainable peanut farming.