269-4 Arsenic and Phosphorus Transfer From Soils to Plants: Unique Ability of Arsenic Hyperaccumulator Pteris Vittata.

See more from this Division: SSSA Division: Soil Chemistry
See more from this Session: Soil-Plant Interactions: Small-Scale Processes and Large-Scale Implications: I

Tuesday, November 5, 2013: 2:15 PM
Tampa Convention Center, Room 11

Jason T. Lessl, Soil and Water Sciences, University of Georgia-Athens, Athens, GA and Lena Q. Ma, 2169 McCarty Hall POB 110290, University of Florida, Gainesville, FL
Abstract:
Arsenate, the most prevalent form of As in soils, is taken up by plant roots via phosphate (Pi) transporters.  However, labile Pi in soils is low and readily depleted by plant uptake.  To compensate, plants have evolved mechanisms to expedite Pi resupply, such as the production of finer roots, exudation of organic acid or acidification of the rhizosphere.  As-hyperaccumulator Pteris vittata L. (PV; Chinese brake fern) has the unparalleled ability to accumulate As from soils with low levels.  This suggests that the physiological aspects of Pi acquisition in PV are unique as Pi and As are chemical analogs.  In As-contaminated soils amended with phosphate rock (PR), a source of low available Pi, PV responded by increasing root biomass containing extensive root hair and adventitious growth, a trait absent in Pi-fertilized soils.  Pore water from the rhizosphere in PR-soils showed increased DOC (oxalic and malic acid) allowing PV to mineralize Pi from PR, even in alkaline soils, a unique observation.  Compared to growth with Pi-fertilizers, agronomic plants cannot adequately mineralize PR, suffering a reduction in biomass and yield.  Comparatively, PV biomass significantly increased in PR-soils in addition to accumulating more As compared to Pi-fertilized soils.  The rhizosphere modifications by PV in a Pi-limiting environment also mobilized As from fractions considered inaccessible for plant uptake.  In addition to providing a sustainable and affordable solution to As-contaminated soils, PV shows potential as a model plant for effective Pi acquisition and utilization.  Given the importance of P as a nonrenewable resource, understanding the P transfer in soil-rhizosphere-plant continuum may garner fundamental clues to develop crops that can efficiently acquire P from unavailable sources in soils.

See more from this Division: SSSA Division: Soil Chemistry
See more from this Session: Soil-Plant Interactions: Small-Scale Processes and Large-Scale Implications: I