Abstract Detail

Ecophysiology

Ebbs, Stephen [1], Whankaew, Sukhuman [2], Rhanor, Thomas [1], Triwitayakorn, Kanakporn [2].

Utilization of cyanide as a supplemental source of nitrogen by plants under nitrogen replete conditions and nitrogen starvation.

Cyanide is generally perceived as a metabolic poison both for plants and animals. Nevertheless, ongoing studies are revealing that at the sub-toxic concentrations more commonly encountered in the natural environment, plants transport and assimilate cyanide as an alternate source of nitrogen, even in the presence of nominal concentrations of ammonium and nitrate. Hydroponic studies using wheat, sorghum, and other plants have shown that exposure to cyanide (labeled with the stable isotope 15N) results in a highly significant enrichment in 15N without a corresponding increase in total plant N, mediated by the assimilatory activity of the β-cyanoalanine pathway. Moreover, under nitrogen starvation, cyanide assimilation by this pathway increases commensurate with an increase in activity of the principal enzyme, β-cyanoalanine synthase. These results indicate that assimilation of cyanide allows the cyanogenic N atom to be incorporated into primary metabolism, ostensibly as an alternate source of ammonium. Single nitrogen source growth experiments conducted with these species showed that when presented at the same concentration, plant growth was similar when nitrate, ammonium, or cyanide was the source of nitrogen, although the relative growth rate of plants grown under the cyanide regime was less than that for nitrate or ammonium. The results suggest that when cyanide is present in the soil environment, the nitrogen from this molecule can serve as a supplement to plant nitrogen metabolism, particularly when other nitrogen sources may be limiting or absent. Cyanide at non-toxic concentration may therefore be benefit to plant mineral nutrition when present in the rhizosphere.

Broader Impacts:

1 - Southern Illinois University Carbondale, Plant Biology, 420 Life Science II, 1125 Lincoln Dr., Carbondale, IL, 62901-6509, USA
2 - Mahidol University, Institute of Molecular Biosciences, 25/25 Phuttamonthon 4 Road, Salaya, Nakhon Pathom , 73170, Thailand

Keywords:
cyanide
nitrogen
cyanoalanine synthase.

Presentation Type: Oral Paper:Papers for Topics
Session: 18
Location: Forsyth Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 2:05 PM
Number: 18004
Abstract ID:30