Saline Stress Alters the Temporal Patterns of Xylem Differentiation and Alternative Oxidase Expression in Developing Soybean Roots1

• Published in: Plant physiology (Bethesda) 1998-06, Vol.117 (2), p.695-701
• Main Authors: Hilal, Mirna, Zenoff, Ana M., Ponessa, Graciela, Moreno, Hortensia, Massa, Eddy M.
• Format: Article
• Language: English
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.117.2.695

We conducted a coordinated biochemical and morphometric analysis of the effect of saline conditions on the differentiation zone of developing soybean (Glycine max L.) roots. Between d 3 and d 14 for seedlings grown in control or NaCl-supplemented medium, we studied (a) the temporal evolution of the respiratory alternative oxidase (AOX) capacity in correlation with the expression and localization of AOX protein analyzed by tissue-print immunoblotting; (b) the temporal evolution and tissue localization of a peroxidase activity involved in lignification; and (c) the structural changes, visualized by light microscopy and quantified by image digitization. The results revealed that saline stress retards primary xylem differentiation. There is a corresponding delay in the temporal pattern of AOX expression, which is consistent with the xylem-specific localization of AOX protein and the idea that this enzyme is linked to xylem development. An NaCl-induced acceleration of the development of secondary xylem was also observed. However, the temporal pattern of a peroxidase activity localized in the primary and secondary xylem was unaltered by NaCl treatment. Thus, the NaCl-stressed root was specifically affected in the temporal patterns of AOX expression and xylem development.