Through two hot summers, the team monitored the sagebrush and discovered hydraulic lift stimulated microbial activity and more than doubled the plants' uptake of nitrogen from the surrounding surface soil at exactly the time they were flowering and setting seed.
"It's a fascinating nutrient acquisition system relying on tiny amounts of water released from plant roots into dry soil at night," explains Cardon. "That tiny flow of water is sustaining soil microbial community activity in the moistened sleeve of soil around sagebrush roots, and the microbes' activities are the natural recycling system making nutrients available to the plants at exactly the time they are flowering and setting seeds." Though microbes seem "high and dry" in surface soils in late summer, hydraulic lift delivers sips of sustaining water to fine roots and rhizosphere microbes, potentially supporting improved sagebrush seed set and even plant productivity in this nitrogen and water-limited ecosystem.
The scientists are now continuing the research at the MBL's Research Greenhouse in Falmouth, Mass, where they are looking at the gene expression in the microbial communities around sagebrush roots that are carrying out the hydraulic lift and exploring how those communities respond to alternating periods of drier and wetter soil around sagebrush roots carrying out hydraulic lift. Greater understanding of hydraulic lift, the researchers say, could aid scientists and growers in finding ways to protect crops from the effects of prolonged drought.
"Microbes house the molecular machines that sustain life on Earth, recycling the nutrient building blocks that plants need to grow," says Cardon. "Given how many billions of human
|Contact: Gina Hebert|
Marine Biological Laboratory