Isolated Green Root Cultures of Triticum aestivum L. Capable of Unlimited Growth on Hormone-Free Nutrient Media

Abstract

When cultivating calli generated from mature germs of spring bread wheat (Triticum aestivum L.), variety Fisht, spontaneous regeneration of chlorophyll-containing green roots sometimes occurred. When isolated from callus, these roots were capable of unlimited growth on hormone-free nutrient media, similar to cultures of hairy roots of dicotyledonous plants. Ordinary wheat roots did not grow under these conditions, while green roots continued to grow even when exposed to 100 mM NaCl. Typical chloroplasts were found in the parenchyma cells of green wheat roots. Approximately equal amounts of chlorophyll a and b were found in green wheat roots; however, their total content was tens of times less than in the leaves. Green roots were characterized by a higher proline content and higher activity of superoxide dismutase, catalase, and peroxidase than ordinary wheat roots, both under normal and under salinity conditions. Green roots may provide an alternative to hairy roots, which are very difficult to generate from grasses and other monocots, for use in both basic research and applied applications.