"Our findings should help scientists understand how plant ecosystems respond to soil calcium depletion and design appropriate strategies to protect the environment," said Zhen-Ming Pei, a Duke University assistant professor of biology who led the study, to be published in the Friday, March 9, issue of the journal Science.
The research was supported by the National Science Foundation, the U.S. Department of Agriculture and Xiamen University in China.
Calcium enters plants dissolved within the water that roots take in from surrounding soil. As the water circulates through a plant, its dissolved calcium gets shuttled where it is needed to give the plant's cells their structural rigidity. To grow, a plant needs a reliable supply of calcium. But calcium supplies coming into the plant cycle up and down over the course of the day, dropping to a minimum at night.
Plants use molecular sensors and flows of chemical messengers to detect and regulate the storage and distribution of vital nutrients such as water and calcium.
To track the calcium sensors in the model mustard plant Arabidopsis, the team used molecules originally found in jellyfish that emit light in response to calcium's presence. To deduce what the sensor does and does not do, the researchers also introduced an "antisense" version of the calcium-sensor protein that abolishes the sensor's effects.
The calcium-sensing molecule in plants, called CAS, was first identified by Pei's group and described in the Sept. 11, 2003, issue of the journal Nature. Arabidopsis is favored for such experiments because it has a relatively short life cycle of eight weeks and its genome has been completely sequenced.
By tracking the glow of the jellyfish molecules, the researchers learned that CAS plays a number of roles in plants. The scientists initially thought it simply monitored changes in levels of dissolved calcium that enters the plant from the outside. They discovered instead that CAS also triggers the release of internal calcium that is stored within the plant via a chemical signaling system.
This coupled system, the researchers deduce, ensures that constant levels of calcium remain available to a plant's cells despite widely varying amounts of the nutrient coming in during each day and night cycle.
"The sensors try to detect how much calcium is there, and they coordinate that level with growth and development," Pei said. "If they detect there is not enough calcium, the plant may elect to hold off on growth and development until it has more calcium. The plant may thus appear not to be doing well."
The findings have prompted Pei to begin a new research program aimed at altering this calcium balancing act to help plants adjust to the ravages of acid rain.
Produced by interactions between water vapor and human-created pollutants, acid rain can disrupt plants' calcium balance by leaching significant amounts of calcium from agricultural and forest soils as well as from plant leaves, according to Pei.
"It has been found that some soils have lost as much as 75 percent of their calcium during the past century," he said. "One way to respond is to add new calcium to the soil. But we can't do that everywhere that it's needed and it is also expensive."
Although acid rain robs soil of much of its calcium, enough is still left for plants to live on, Pei added. But he suspects that sensors like CAS may misinterpret "less" as "too little" in those plants and unnecessarily signal for growth shutdowns. Perhaps a plant's calcium sensors could instead be tricked into interpreting "less" as "still enough" and keep building new cell walls, he suggested.
As a preamble to such genetic engineering, Pei is now leading a study in his native China that will evaluate the physiology of various plants affected by acid rain. "It is in the south of China where acid rain is huge because of industry," he said. "China is becoming the factory for the United States.
"We will monitor calcium changes in the soil there, and then clone calcium receptors from various plant species to see whether those receptors are responsible for growth and how they respond to acidity," he said. "Some plants grow terribly under acid rain, but others grow very well."
Monte Basgall | EurekAlert!
Atomic-level motion may drive bacteria's ability to evade immune system defenses
24.04.2017 | Indiana University
Two-dimensional melting of hard spheres experimentally unravelled after 60 years
24.04.2017 | University of Oxford
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
24.04.2017 | Physics and Astronomy
24.04.2017 | Materials Sciences
24.04.2017 | Life Sciences