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Angiosperm Flora of India

Stagnant deoxygenated growth enhances root suberization and lignifications, but differentially affects water and NaCl permeabilities in rice (Oryza sativa L.) roots

Publication Type:Journal Article
Year of Publication:2011
Authors:RANATHUNGE, KOSALA, LIN, JINXING, Steudle, E, Schreiber, L
Journal:Plant, Cell & Environment
Volume:34
Issue:8
Date Published:2011
ISBN Number:1365-3040
Keywords:endodermis, exodermis, hydraulic conductivity, Lignin, Oryza, Oryza sativa, radial oxygen loss, reflection coefficient, suberin
Abstract:

It has been shown that rice roots grown in a stagnant medium develop a tight barrier to radial oxygen loss (ROL), whereas aerated roots do not. This study investigated whether the induction of a barrier to ROL affects water and solute permeabilities. Growth in stagnant medium markedly reduced the root growth rate relative to aerated conditions. Histochemical studies revealed an early deposition of Casparian bands (CBs) and suberin lamellae (SL) in both the endodermis (EN) and exodermis, and accelerated lignification of stagnant roots. The absolute amounts of suberin, lignin and esterified aromatics (coumaric and ferulic acid) in these barriers were significantly higher in stagnant roots. However, correlative permeability studies revealed that early deposition of barriers in stagnant roots failed to reduce hydraulic conductivity (Lpr) below those of aerated roots. In contrast to Lpr, the NaCl permeability (Psr) of stagnant roots was markedly lower than that of aerated roots, as indicated by an increased reflection coefficient (σsr). In stagnant roots, Psr decreased by 60%, while σsr increased by 55%. The stagnant medium differentially affected the Lpr and Psr of roots, which can be explained in terms of the physical properties of the molecules used and the size of the pores in the apoplast.

URL:http://dx.doi.org/10.1111/j.1365-3040.2011.02318.x
Short Title:Plant, Cell & Environment
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