Silicon Deposition in the Roots of Hordeum sativum Jess, Avena sativa L. and Triticum aestivum L.

Abstract

Electron-probe microanalysis was used to investigate the location of silicon at the proximal end of the seminal and adventitious roots, of almost mature field-grown specimens of Hordeum sativum Jess., Avena sativa L. and Triticum aestivum L. In the seminal roots silicon was confined to the endodermis, where it was present in the thickened inner tangential and radial walls. The outer tangential walls also contained silicon in all of the cells in wheat and in occasional cells in barley and oats. The adventitious roots of the three cereals displayed differences in silicon deposition. In barley, silicon was present in all the walls of the endodermal cells, whereas in oats it was only located in the inner tangential and radial walls. Wheat showed cultivar differences, no silicon was detected in Capelle Desprez, but it was present in the thickened endodermis of Little Joss and Hustler. In all the samples studied silicon was absent from the sub-epidermal sclerenchyma layer. The results are discussed in relation to the possible functions of the endodermis and the signficance of silicification.