DURHAM, N.C. -- A new understanding of how plants manage their internal calcium levels could potentially lead to genetically engineering plants to avoid damage from acid rain, which robs soil of much of its calcium.
"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.