HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Azaizeh, H. A. Articles by Terry, N. Search for Related Content PubMed Articles by Azaizeh, H. A. Articles by Terry, N. Agricola Articles by Azaizeh, H. A. Articles by Terry, N.

Microbial Selenium Volatilization in Rhizosphere and Bulk Soils from a Constructed Wetland

S. Gowthaman

N. Terry^*

Dep. of Plant and Microbial Biology, 111 Koshland Hall, Univ. of California, Berkeley, CA 94720.

^* Corresponding author.

ABSTRACT

The potential of rhizosphere and bulk soil microbes to volatilize selenate, selenite, and selenomethionine was studied in liquid cultures under controlled conditions. Microbes cultured from the rhizosphere of bulrush (Scirpus robustus) plants showed higher Se volatilization than those from bulk soil of a flow-through, constructed wetland area contaminated with selenite. The data show that bacteria are the dominant microbes involved in Se volatilization; fungi contribute relatively little to this process. Bactericides significantly decreased both Se volatilization and the number of culturable bacteria in rhizosphere cultures compared to an untreated control. In the absence of added C, Se volatilization was greatest from selenomethionine, then selenite, then selenate. Aeration substantially increased the percentages of Se volatilized from rhizosphere soil cultures to which no C was added. Up to 95, 21, and 3% of the Se was volatilized from selenomethionine, selenite, and selenate, respectively. When both C and aeration treatments were applied to the rhizosphere cultures, the corresponding percentages changed to 20, 57, and 4%, that is, selenomethionine volatilization by rhizosphere microbes decreased when C was added while selenite volatilization substantially increased. Since selenite volatilization was the greatest when rhizosphere microbes were supplied with C and aeration, we suggest that microbes in this selenite-contaminated wetland are adapted to volatilize Se by using C released from roots, and that Se volatilization may be enhanced by oxygen and environmental conditions provided by the plants.

current address: The Galilee Regional Research and Development Center, P.O. Box 536, Eilabun 16972, Israel;

current address: Dep. of Plant Cell Biotechnology, Central Food Technological Research Inst., Mysore 570013, India;

Received for publication May 31, 1996.

This article has been cited by other articles:

				S. Gao, K. K. Tanji, Z. Q. Lin, N. Terry, and D. W. Peters Selenium Removal and Mass Balance in a Constructed Flow-Through Wetland System J. Environ. Qual., July 1, 2003; 32(4): 1557 - 1570. [Abstract] [Full Text] [PDF]

				H. A. Azaizeh, N. Salhani, Z. Sebesvari, and H. Emons The Potential of Rhizosphere Microbes Isolated from a Constructed Wetland to Biomethylate Selenium J. Environ. Qual., January 1, 2003; 32(1): 55 - 62. [Abstract] [Full Text] [PDF]

				M. P. de Souza, D. Chu, M. Zhao, A. M. Zayed, S. E. Ruzin, D. Schichnes, and N. Terry Rhizosphere Bacteria Enhance Selenium Accumulation and Volatilization by Indian Mustard Plant Physiology, February 1, 1999; 119(2): 565 - 574. [Abstract] [Full Text]