The influence of composition of the basal medium on the growth and morphogenesis of cultured sitka spruce (Picea sitchensis) tissues
1990
Selby, C. | Harvey, B.M.R.
In vitro culture of Picea sitchensis (Bong.) Carr. needle explants on a number of basal culture media indicated that a complex mixture of organic additives was neither essential nor stimulatory. Adventitious bud production occurred at inorganic nitrogen levels of 15–60 × 10−3M and 7.5–30 × 10−3 M in the adventitious bud induction and elongation media, respectively, when a well-balanced ratio of NH4+:NO3− was maintained. However, necrosis was increased at the highest level of inorganic nitrogen. Organogenesis was more sensitive to changes in the ratio of NH4+:NO3−. Complete replacement of NH4+ with NO3− during the adventitious bud induction passage severely inhibited organogenesis, indicating that a reduced form of nitrogen may be essential for adventitious bud differentiation. Conversely, a high proportion of NH4+ in either the adventitious bud induction or elongation medium increased tissue necrosis and inhibited bud induction, reflecting the potential toxicity of this ion. Explants from different individual trees were found to vary considerably in their morphogenetic responses, but NH4+:NO3− ratios of 1:5 or 1:2 were o ptimal for all individual trees which developed adventitious buds from needle cultures.
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