Plants are adapting to rising CO2 rates

SOUTHAMPTON, England, Aug. 24 (UPI) -- New analysis of molecular signatures suggests plants are adapting the higher rates of carbon dioxide in the atmosphere.

Previous research has suggested rising CO2 levels would encourage accelerated plant growth in the short term, and indeed, greening has been documented across much of the globe.

But as Gail Taylor, a professor of biological sciences at the University of Southampton, recently pointed out: "[Few studies have] given us any insight into the long-term impacts of rising CO2 over multiple generations, and none have been undertaken on the molecular signature underpinning such adaptation."

Taylor is the lead author of a new study on the longer-term effects of CO2 rates on plant physiology, published this week in the journal Global Change Biology.

Part of the reason so little research has addressed the topic is that few living plants have been exposed to heightened CO2 rates for a prolonged period of time.

Some have, however, and Taylor and her colleagues set out to study them.

Plant communities growing near CO2 springs -- vents, often near volcanic systems, leaking high concentrations of carbon dioxide -- have been exposed to the greenhouse gas for many generations. Taylor and her fellow researchers compared the molecular signatures of plantago lanceolata plants living near a spring in Bossoleto, Italy, to plants living elsewhere.

Scientists identified markedly different patterns of gene expression in the plants living near a CO2 spring. When two specimens of the plant species were subjected to the same environment, the plant from the spring grow larger and featured higher rates of photosynthesis.

"Plants from the spring sites had differences in the expression of hundreds of genes," Taylor said.

Prior to their experiments, the scientists predicted that the plant's stomatal pores -- small leaf holes that control the uptake of CO2 and the evaporation of water -- would shrink in number over time. Study results suggest plants exposed to CO2 developed more pores.

"We don't understand the full consequences of this developmental change but it shows that plants will adapt in unpredictable ways to future CO2 over multiple generations," Taylor concluded. "This question is pressing -- we need to know how food crops may evolve over future generations in response to the changing climate, whether planetary greening is likely to continue and the impacts of this for global nature conservation."