Shoot Regeneration from Leaf Tißues of Phlox paniculata L.

Abstract

Summary A highly efficient shoot regeneration system from greenhouse-grown leaf tisues of Phlox paniculata cvs. Franz Schubert and Prospero was developed. In a preliminary experiment, both TDZ and BA (at 5 μmol/L each) along with 2.5 μmol/L IAA, induced almost a 100 % regeneration frequency for both genotypes, especially when explants were grown without any dark treatment. Moreover, significant differences were observed in regenerability of explants collected from first, second, and third nodes. In a factorial experiment with four BA or four TDZ levels (0.25, 1, 3, and 5 μmol/L) along with three IAA levels (0, 0.5 and 1.0 μmol/L), Franz Schubert, leaf explants exhibited significant differences in shoot organogenesis (mean number of sites of organogenesis/explant, callus development, % explants with>6 shoots/explant) and overall quality of shoot regenerants (mean length of longest shoot, hyperhydration). Results of a principal component analysis indicated that, overall, BA was more effective than TDZ in inducing more shoots and more regeneration sites per explant, and with les callus development. However, hyperhydration (vitrification) of shoot regenerants on media containing 1 μmol/L BA and 0 or 0.5 μmol/L IAA prevented further elongation of these shoots. In another factorial experiment, low levels of both BA (0.5 to 1.5 μmol/L) and IAA (0 to 1 μmol/L) were also investigated. It was observed that all shoot organogenesis occurred along the cut margins of leaf segments and without an intervening callus stage when explants were grown on an MS medium supplemented with 0.5 μmol/L BA and 0.5 μmol/L IAA. Elongation of shoot regenerants was achieved when these were transferred to an MS medium without growth regulators.