Influence of phenolics on micropropogation of Eucalyptus Marginata
The Australasian Plant Breeding Association Inc.
Faculty of Computing, Health and Science
School of Natural Sciences
Phenolics have been extracted form micropropagated shoots of Eucalyptus marginata and analysed using Folin-Ciocalteau reagent and high performance liquid chromatography. Significant differences were obtained between clones in percentage rooting, total phenolic content and the levels of particular phenolics ( e.g. ferulic acid, p-coumaric acid, m-coumaric acid (tentative identification)). Total phenolic content Tanged from 11.6 ± 3.5 mg g-1 fresh weight (fwt) to 58.4 ± 4.7 mg g·1 fwt. The levels of individual phenolics also varied between clones with, in most cases, the same peaks appearing for all clones. One particular phenolic, that is yet to be identified, dominated the phenolic profile. The inclusion of the phenolic phloroglucinol into the shoot 1:11u1tiplication medium had two effects on the clones tested. Firstly, the levels of total phenolics increased when the shoots were grown on media containing 10 or 20 mM phloroglucinol. Secondly, when these shoots were transferred to root induction medium root production was significantly increased. For one clone, the increase was from 8 11 8% to 48 11 10% and for the other rooting increased from_ 48 11 12% to 80 11 9%. This significantly adds to the capacity to produce large numbers of these clones. Inclusion of phloroglucinol in the root induction medium increased rooting for some clones but this was less effective than its inclusion in the multiplication medium prior to root induction.