Increasing the longevity of some native Australian cut flowers

Final report for the Australian Flora Foundation funded project:

Virginia G. Williamson, The University of New England, Armidale, N.S.W.

Longevity of cut Boronia heterophylla flowers was tested using nine different solutions, and was found to be significantly increased from 6.3 days (in distilled water) to 12.9 days by pulsing the stems with silver thiosulphate (STS), and then transferring them to distilled water. The use of 50 ppm chlorine resulted in a decreased vase life of 4.2 days.

The number of colony forming units of bacteria in the vase solutions was determined, and the solution which had the significantly greatest number of bacteria was also the solution in which flowers lasted the longest: the STS pulse, then distilled water, it would appear that the vase life of B. heterophylla is influenced by the vase solution composition rather than the number of bacteria present, although, as the type of bacteria was unable to be determined in this trial, that aspect cannot be precluded.

A preliminary vase life trial has just been completed using B. muelleri cv. Sunset Serenade, but these results have not been analysed. Leptospermum petersonii has not yet flowered, and I have doubts about the suitability of L. rotundifolium as a cut flower because the petals reflex within 24 h of opening. Grevillea banksii has not yet flowered, and G. johnsonii has only provided a small number of flowers: not enough to continue on from the preliminary vase life trial conducted last year.

A paper entitled ‘The influence of vase solution bacteria on the longevity of cut Boronia heterophylla flowers’ was presented at La Trobe University in October to the 1992 Australian Society of Plant Physiologists’ annual conference.