Sulfur dioxide flux into leaves of Geranium carolinianum L. : evidence for a nonstomatal or residual resistance

Journal Article · Sat Jan 01 04:00:00 EST 1983 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.72.1.237· OSTI ID:5959936

Taylor, Jr, G E; Tingey, D T

The concurrent exchange of SO/sub 2/ and H/sub 2/O vapor between the atmosphere and foliage of Geranium carolinianum was investigated using a whole-plant gas exchange chamber. Total leaf flux of SO/sub 2/ was partitioned into leaf surface and internal fractions. The emission rate of SO/sub 2/-induced H/sub 2/S was measured to develop a net leaf budget for atmospherically derived sulfur. Stomatal resistance to SO/sub 2/ flux was estimated by two techniques: (a) R/sub s//sup SO/sub 2// from SO/sub 2/ data using analog modeling techniques and (b) R/sub s//sup SO/sub 2// from analogy to H/sub 2/O (i.e. 1.89 R/sub s//sup H/sub 2/O/). The emission of H/sub 2/S was positively correlated with the rate of SO/sub 2/ flux into the leaf interior. An accounting of the simultaneous, bidirectional flux of gaseous sulfur compounds during pollutant exposure showed that sulfur accumulation in the leaf interior of G. carolinianum was 7 to 15% lower than that estimated solely from mass-balance calculations of SO/sub 2/ flux data (i.e. ignoring H/sub 2/S emissions). The estimate of stomatal resistance to pollutant flux from the SO/sub 2/ data (R/sub s//sup SO/sub 2/'/) was consistently less than the simultaneous estimate derived from analogy to H/sub 2/O vapor (R/sub s//sup SO/sub 2//). The resultant of R/sub s//sup SO/sub 2/ - R/sub s//sup SO/sub 2//, which was always negative, is indicative of a residual resistance to SO/sub 2/ flux into the leaf interior. On a comparative basis, SO/sub 2/ molecules experienced less pathway resistance to diffusion than effluxing H/sub 2/O molecules. It is proposed that the SO/sub 2/:H/sub 2/O path length ratio is less than unity, as a consequence of the pollutant's high water solubility and unique chemical reactivity in solution. Thus, the diffusive paths for H/sub 2/O and SO/sub 2/ in G. carolinianum are not completely synonymous. 47 references, 6 figures, 2 tables.

• Research Organization: Oak Ridge National Lab., TN
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5959936
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 72; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

560303* -- Chemicals Metabolism & Toxicology-- Plants-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL ACCUMULATION
CHALCOGENIDES
CLEARANCE
DATA
EXCRETION
EXPERIMENTAL DATA
FLOWERS
FOLIAR UPTAKE
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
INFORMATION
LEAVES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
UPTAKE