| heal.abstract |
Callus cultures were initiated from mature excised embryos of winter wheat on Murashige and Skoog (MS) medium supplemented with either 0, 3, 6 or 9 g/l NaCl and various combinations of growth regulators. Callus induction tales were virtually 100% on every medium used, while the growth of calli during the induction phase was retarded at higher NaCl concentrations. Application of NaCl and auxin at high concentrations during the induction and proliferation phases strongly inhibited shoot induction. In addition, a competition between root induction and shoot induction was clearly observed. Conversely, rhizogenesis was not significantly decreased under saline conditions and was actually favoured at high NaCl (≤ 6 g/l) concentrations, especially when 2.4-D was used as the only auxin for callus induction. Roots induced at lower NaCl levels were significantly longer, thinner, lighter-coloured and had fewer hairs than roots induced on 6 or 9 g/l NaCl. Roots induced on NaCl-free medium also had fewer but larger cortex parenchymatic cell layers and a wider stele compared with roots induced on the highest NaCl level. The best plant regeneration (simultaneous root and shoot formation) rates were observed when calli were induced on 2 mg/l 2,4-D and subcultured on 1 mg/l NAA and 3 g/l NaCl. |
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