Date of Award

2013

Degree Type

Thesis

Degree Name

Master of Science

School

School of Natural Sciences

Faculty

Faculty of Health, Engineering and Science

First Advisor

Dr Ian Bennett

Second Advisor

Dr Mary Boyce

Abstract

The objective of this study was to improve the existing shoot multiplication protocol for Verticordia grandis (McComb, Arthur & Newll, 1986; Newell, Growns & McComb, 2005) and to investigate and establish reliable root induction and acclimatisation protocols to enhance survival of micropropagated plantlets. It was envisaged that these protocols would be successful in micropropagation, growth and survival of different V. grandis clones and possibly applicable to other Verticordia species.


The elongation of in vitro Verticordia shoots on multiplication media was improved by reducing the concentration of BAP from 1μM to 0.25 μM, which resulted in a more uniform shoot length of 4.5 – 5 cm; necessary for root induction experiments. The root induction protocol was optimised by determining the appropriate auxin concentration (80μM indole butyric acid; IBA) with an exposure time of 6 days. Acclimatisation and survival was greatly improved by transferring the IBA pulsed shoots to ex vitro conditions consisting of a free draining and aerated substrate (a mixture of peat and perlite 1:3) in crack pots. These were initially placed into a greenhouse (with controlled temperature & light conditions) in order to maintain high humidity. Over time humidity was reduced and after 112 days the plantlets were transferred to larger pots, containing fresh soil (peat/perlite/sand = 1:1:1) and placed in a shade house with a regular watering regime. Long-term survival was monitored and after 252 days survival was over 70%. The declining survival rates after this time has made it evident that field performance and long-term survival needs further investigation. The application of the improved shoot multiplication and root induction protocols on other V. grandis clones produced survival rates of 0 to 62.5% (depending upon clone) over 252 days.

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