The effect of macroelements in the induction of embryogenic callus from immature embryos of wheat ( Triticum aestivum L.)

Abstract

The effects of the concentrations of each of the five MS macroelements on the induction and morphology of embryogenic callus from immature embryos of wheat were investigated. Relatively high induction frequencies of epiblast callus were obtained over wide ranges of concentrations of the five salts: NH 4NO 3 10–20 mM, KNO 3 0–40 mM, KH 2PO 4 0.31 –10 mM, CaCl 2 0–24 mM and MgSO 4 0–48 mM. For induction of scutellum callus, the optimum concentration range of salts was narrower than that for induction of epiblast callus: KNO 3 0–20 mM, CaCl 2 0–24 mM and MgSO 4 0.19–12 mM. The presence of NH 4NO 3 was essential for the proliferation of embryogenic callus and a relatively high concentration (10 mM) was found to be optimum for the induction of both scutellum and epiblast callus. The presence of CaCl 2, MgSO 4 and KH 2PO 4 was not essential for the initiation of epiblast callus but strongly affected the further development of this callus and its differentiation potential. Phosphate showed a strong stimulation of the formation of leaf structures on the callus. The frequency of white callus was enhanced by four of the five macroelements at high concentrations and as high as 60% of primary callus could form white callus on some media. As the formation of typical embryoids of wheat has been previously reported as occurring with white callus, this study may provide a useful base for further work on factors affecting the formation of typical embryoids in wheat callus.