Possible impacts of elevated CO2 and temperature on growth and development of grain legumes – review

Authors: ADIREDDY, RAJANNA - Oak Ridge Institute For Science And Education (ORISE); Anapalli, Saseendran; Reddy, Krishna; Mubvumba, Partson; George, Justin

Submitted to: Journal of Agronomy and Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2024
Publication Date: 12/2/2024
Citation: Adireddy, R.G., Anapalli, S.S., Reddy, K.N., Mubvumba, P., George, J. 2024. Possible impacts of elevated CO2 and temperature on growth and development of grain legumes – review. Journal of Agronomy and Crop Science. Environments 2024, 11, 273. https://doi.org/10.3390/environments11120273.
DOI: https://doi.org/10.3390/environments11120273

Interpretive Summary: Fossil fuel use for human energy needs has contributed to earth-warming greenhouse gas buildup in the atmosphere. Carbon dioxide is the most abundant greenhouse gas and the raw material used by plants for the photosynthetic fixation of dry matter (carbohydrates), which can result in better crop growth and harvested yields. However, the associated increase in air temperatures causes heat stress in crop plants. The plants also grow faster with less time for accumulating biomass and yield. In this context, scientists with the USDA ARS, Crop Production Systems Research Unit, Stoneville, MS, reviewed and summarized the available literature on the impacts of increased CO2 concentrations and temperatures in the air on legume growth and development, seed nutritional qualities, soil health, and insect behavior. The work was based on a Web of Science and Google Scholar collection of peer-reviewed papers, reports, and reviews. The review can help researchers to develop agronomic strategies to alleviate the impacts of climate change while also assisting breeders in developing novel genotypes that are more adaptable to the effects of climate change.

Technical Abstract: Carbon dioxide (CO2) is the most abundant greenhouse gas (GHG) in the atmosphere and the substrate for the photosynthetic fixation of carbohydrates in plants. Increasing GHG from anthropogenic emissions is warming the earth-atmospheric system at an alarming rate and changing its climate, which can affect photosynthesis and other biochemical reactions in crop plants favorably or unfavorably, depending on plant species. For the substrate role in plant carbon reduction reactions, CO2 concentration ([CO2]) in air potentially enhances photosynthesis. However, N uptake and availability for protein synthesis can be a potential limiting factor in enhanced biomass synthesis under enriched [CO2] conditions across species. Legumes are C3 plants and symbiotic N fixers and are expected to benefit from enhanced [CO2] in the air. However, the concurrent increase in air temperatures with enhanced [CO2] demands more detailed investigations on the effects of [CO2] enhancement on grain legume growth and yield. In this article, we critically reviewed and presented the online literature on growth, phenology, photosynthetic rate, stomatal conductance, productivity, soil health, and insect behavior under elevated [CO2] and temperature conditions. The review revealed that specific leaf weight, pod weight, and nodule number and weight increased significantly under elevated [CO2] of up to 750ppm. Under elevated [CO2], two mechanisms affected were photosynthesis rate (increased) and stomatal conductivity (decreased), which helped enhance water use efficiency in the C3 legume plants to achieve higher yields. Exposure of legumes to elevated levels of [CO2] when water stressed, resulted in an increase of 58% in [CO2] uptake, 73% in transpiration efficiency, and 41% in rubisco carboxylation and decreased stomatal conductance by 15-30%. The elevated [CO2] enhanced soybean yield by 10-101 %, peanut by 28-39%, mung bean by 20-28%, chickpea by 26-31%, and pigeon pea by 31-38% over ambient [CO2]. However, seed nutritional qualities like protein, Zn, and Ca were significantly decreased. Increased soil temperatures stimulate microbial activity, spiking organic matter decomposition rates and nutrient release into the soil system. Elevated temperatures impact insect behavior through higher plant feeding rates, posing an enhanced risk of invasive pest attacks in legumes. However, further investigations on the potential interaction effects of elevated [CO2] and temperatures and extreme climate events on growth, seed yields and nutritional qualities, soil health, and insect behavior are required to develop climate-resilient management practices for sustainable legume production systems.