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Apoplastic barriers effectively block oxygen permeability across outer cell layers of rice roots under deoxygenated conditions: roles of apoplastic pores and of respiration
Author(s) -
Kotula Lukasz,
Ranathunge Kosala,
Steudle Ernst
Publication year - 2009
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2009.03021.x
Subject(s) - apoplast , oryza sativa , respiration , oxygen , hydroponics , oxygen permeability , chemistry , aeration , avena , botany , oxygene , biophysics , horticulture , cell wall , biology , biochemistry , organic chemistry , gene
Summary• Despite the importance of the barrier to oxygen losses of the roots of hygrophytes growing in wet environments devoid of oxygen, there are few data available on permeability coefficients for O 2 across outer root cell layers ( P OPR ) and how they may change in response to low O 2 . • A gas perfusion technique was used to measure the P OPR of rice ( Oryza sativa ) plants grown in either aerated or deoxygenated solution. The contributions of the apoplast and of living cells to the overall P OPR were characterized either by blocking apoplastic pores with precipitates of brown Cu 2 [Fe(CN) 6 ] or by killing cells with 0.1 N HCl. • Compared with that of plants from aerated hydroponics, the P OPR of plants grown in deoxygenated medium was smaller by an order of magnitude. Precipitates resulting from CuSO 4 /K 4 [Fe(CN) 6 ] treatment only formed in plants grown in aerated solution, where they reduced the P OPR by 5–20%. Killing of root segments with HCl increased P OPR in plants grown in both conditions by 20–55%. • The results indicated that apoplastic barriers effectively restricted radial O 2 loss. The relative role of the respiratory O 2 consumption of root peripheral layers increased as P OPR decreased.