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Fate of oxygen losses from Typha domingensis (Typhaceae) and Cladium jamaicense (Cyperaceae) and consequences for root metabolism
Author(s) -
Chabbi Abad,
McKee Karen L.,
Mendelssohn Irving A.
Publication year - 2000
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.2307/2656644
Subject(s) - aerenchyma , biology , rhizosphere , oxygen , botany , typha , horticulture , ecology , chemistry , wetland , genetics , organic chemistry , bacteria
The objective of this work was to determine whether radial oxygen loss (ROL) from roots of Typha domingensis and Cladium jamaicense creates an internal oxygen deficiency or, conversely, indicates adequate internal aeration and leakage of excess oxygen to the rhizosphere. Methylene blue in agar was used to visualize the pattern of ROL from roots, and oxidation of a titanium‐citrate solution was used to quantify rates of oxygen leakage. Typha 's roots had a higher porosity than Cladium 's and responded to flooding treatment by increasing cortical air space, particularly near the root tips. A greater oxygen release, which occurred along the subapical root axis, and an increase in rhizosphere redox potential ( E h ) over time were associated with the well‐developed aerenchyma system in Typha. Typha roots, regardless of oxygen release pattern, showed low or undetectable alcohol dehydrogenase (ADH) activity or ethanol concentrations, indicating that ROL did not cause internal deficiencies. Cladium roots also released oxygen, but this loss primarily occurred at the root tips and was accompanied by increased root ADH activity and ethanol concentrations. These results support the hypothesis that oxygen release by Cladium is accompanied by internal deficiencies of oxygen sufficient to stimulate alcoholic fermentation and helps explain Cladium 's lesser flood tolerance in comparison with Typha.