title: X-ray absorption spectroscopy study shows that the rapid selenium volatilizer, pickleweed (Salicornia bigelovii Torr.), reduces selenate to organic forms without the aid of microbes.
abstract: In many plant species, selenium (Se) volatilization is limited by the reduction of selenate and its chemical conversion to organic Se compounds, a process that may be facilitated by rhizosphere microbes. This study was conducted to determine if pickleweed (Salicornia bigelovii Torr.), which is characterized by having high rates of Se volatilization from selenate, is able to reduce selenate into organic forms of Se axenically, or whether it requires the presence of microbes. X-ray absorption spectroscopy analysis showed that shoots and roots of pickleweed plants supplied with 50 microM selenate accumulated Se predominantly in organic Se forms (about 65-75% of the total accumulated Se), regardless of whether the plants were grown axenically or in the presence of microbes. The results suggest that, unlike other species for which selenate reduction appears to be rate limiting. e.g. Indian mustard (Brassica juncea L.) and broccoli (Brassica oleracea L.), pickleweed is unusual in that it has an enhanced capacity to reduce selenate to organic forms that is independent of the presence of rhizosphere microbes.
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley 94720-3102, USA.
authors.forename: A
authors.initials: A
authors.lastname: Lee
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Lin
authors.forename: I J
authors.initials: IJ
authors.lastname: Pickering
authors.forename: N
authors.initials: N
authors.lastname: Terry
mesh_terms: D019663:Chenopodiaceae / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D009942:Organometallic Compounds / Q000378:metabolism; D016566:Organoselenium Compounds; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D064586:Selenic Acid; D012643:Selenium / Q000378:metabolism; D018036:Selenium Compounds / Q000378:metabolism* / Q000494:pharmacology; D018038:Sodium Selenite / Q000378:metabolism / Q000494:pharmacology; D013057:Spectrum Analysis / Q000379:methods*; D014835:Volatilization
chemical_list: D009942:Organometallic Compounds; D016566:Organoselenium Compounds; D018036:Selenium Compounds; D012643:Selenium; D018038:Sodium Selenite; D064586:Selenic Acid; C013503:dimethylselenide