Cold Storage of Selected Members of the Proteaceae and Australian Native Cut Flowers Rod Jones and John Faragher

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O R T

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26(11):1395-1397. 1991.

Cold Storage of Selected Members of

the Proteaceae and Australian Native

Cut Flowers

Rod Jones and John Faragher

Institute of Plant Sciences, Knoxfield, Department of Agriculture,

Victoria, PO Box 174, Ferntree Gully 3156 Australia

Additional index words. Leucospermum spp., Protea spp., Leucadendron, Thryptomene

calycina , Telopea speciosissima , Chamelaucium uncinatum , Vertcordia spp . ,

Anigozanthos spp., postharvest physiology, vase life

Abstract. Five members of the Proteaceae and 13 Australian native cut flower culti-

vars were stored for 35 days under standard conditions at 1C to assess their ability to

withstand long-term storage and transport. Protea cynaroides L., Leucadendron ‘Silvan

Red’, Leucospermum ‘Firewheel’, Thryptomene calycina (Lindl.) Stapf., Telopea spe-

ciosissima R. Br., and Verticordia grandtiflora Endl. retained a vase life of at least 7

days after 21 days of storage. Leucospermum cordifolium Salisb. ex Knight, Protea

neriifoli R. Br., Chamelaucium uncinatum ‘Alba’, C. uncinatum ‘Purple Pride’, Ver-

ticordia monadelpha Turcz., Verticordia plumosa (Desf.) Druce, and Verticordia nitens

(Lindl.) Schau. suffered a decline in vase life ranging from 31% to 100% after 14 to

21 days of storage. Species of Verticordia and Chamelaucium were particularly suscep-

tible to fungal infection. Anigozanthos pulcherrimus Hook. and the Anigozanthos cul-

tivars Ruby Delight, Bush Harmony, Bush Haze, and Gold Fever all showed a significant

reduction in vase life after 14 days of storage compared with unstored controls.

Early research on the postharvest handling

of cut flowers demonstrated the potential of

dry storage in the rose, carnation, and chry-

santhemum (Fischer, 1952; Hauge et al.,

1947; Neff, 1939; Thornton, 1930). Recent

studies have also concentrated on storage

protocols for traditional flower crops (Gosz-

czynska and Rudnicki, 1988; Hardenburg et

al., 1986) The rapid expansion of the Aus-

tralian cut flower industry has resulted in a

marked increase in the export trade of Aus-

Received for publication 21 Mar. 1991. This work

was partially- funded by a grant from the Rural

Industry Research Development Corn. We thank

Ausflora Pacific Pty. Ltd.; The Australian Protea

Growers Assn., Australian Flower Exporters Ply.

Ltd, and Growth Industries Ltd. for supplying the

flowers used in this study. We are also greatly

indebted to Janyce Truett for her skilled technical

assistance and Peter Franz for assistance with sta-

tistical analysis. The cost of publishing this paper

was defrayed in part by the payment of page

charges. Under postal regulations, this paper

therefore must be hereby marked advertisement

solely to indicate this fact.

H

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. 26(11), N

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1991

tralian native cut flowers, particularly Cha-

melaucium uncinatum (Geraldton waxflower),

Anigozanthos cultivars (kangaroo paw), and

members of the Proteaceae. In the few stor-

age trials conducted using these crops, the

vase life of Telopea speciosissima (waratah)

was reduced by 25% after 28 days of storage

at 1C (Faragher, 1986), while vase life in

Anigozanthos rufus and Chamelaucium un-

cinatum was significantly reduced by 14 days

of storage at 1C (Joyce, 1988; Seaton and

Joyce, 1989). P. cynaroides and L. cordi-

folium withstood 42 days of dry storage at

2C without reduction in vase life (Haasbroek

et al., 1973; Ireland et al., 1967; Meynhardt,

1976). During a transient period of high air-

freight costs, successful seafreight of cut

Protea flowers from Cape Town, South Af-

rica, to Rotterdam, Holland, was completed

by several South African Protea growers in

1980 using refrigerated containers, but no

data exist on storage and transport protocol

(J. Wood, personal communication). Stor-

age protocols and conditions differed widely

between these trials, and in many cases the

criteria for determining the end of vase life

were not cited. The aim of this study was to

assess the storage capacity of a wide range

of commercial Australian native cut flowers

and members of the Proteaceae family using

specific vase life criteria and under a stan-

dard storage protocol. Cultivars that were

suited to long-ten dry storage were deter-

mined to be those that retained a vase life of

at least 7 days after 21 days of storage.

Verticordia spp. were obtained from

Western Australia and airfreighted to Knox-

field within 30 h of harvest. The Chamelau-

cium and Anigozanthos cultivars were

harvested from commercial flower growers,

cooled for 6 h, and transported dry for 6 to

12 h to the laboratory. All other flowers were

harvested locally and transported in water,

arriving at the laboratory within 3 h of har-

vest. Control, unstored flowers were sprayed

with 1 g iprodione/liter (wettable powder,

50% a.i.; commercial name: Rovral, Rhone

Poulenc, Melbourne, Australia) and placed

in water at 1C for 24 h, then removed to 20C

for vase life assessment. Stored blooms were

thoroughly sprayed with 1 g iprodione/liter,

allowed to dry, and kept at 1C for 24 h while

standing in distilled water. Preliminary trials

indicated that a pre- and poststorage treat-

ment in water lasting at least 24 h was most

effective (data not shown).

Flowers were bunched and tightly wrapped

in two layers of newsprint and placed in low-

density polyethylene bags (~38 µm thick).

These were then placed in fiberboard flower

boxes (1030 x 370 x 160 mm) and stored

in a room set at 1 ± 1C and 80% ± 5%

relative humidity (RH). A nonstored control

group was placed directly into the evaluation

Table 1. Criteria used for determining end of

vase life.

1395

Fig. 1. Fitted curves representing changes in vase

life after dry storage at 1C in members of the

Proteaceae. 1) L. cordifolium ( r ); Y =

10.66 

– 

0 . 1 2 9 X  

– 

0.00596X; Adj. R

2 

=

60.4. SE = 0.128X; 0.00353X

2

. 2) Firewheel

( 

t ); Y = 9.68 + 0.033X - 0.00756X

2

; Adj.

R

2 

= 39.4. 

S E

= 0.137X; 0.00378X

2

. 3) P.

cynaroides 

(◊); 

Y = 7.83 - 0.0883X; Adj.

R

2 

= 17.9. 

SE 

= 0.0389X. 4) P. neriifolia

(∆); 

Y = 6.58 – 0.374X + 0.00542X

2

; Adj.

R

2 

= 76.4. SE = 0.0508X; 0.004X2. Where  

Y = vase life (days); X = storage time (days).

room. After storage, the flowers were un-

wrapped, the stems recut and rehydrated at

1C in distilled water for 24 h, with flower

heads covered with a polyethylene bag sim-

ilar to that used in packing to increase rela-

tive humidity in the air surrounding the flower

heads. Vase life was evaluated at 20C and

55% to 65% RH under constant light (10

µmol·m

-2

·s

-1

) supplied by cool-white flu-

orescent lamps. Criteria used to specify the

end of vase life for each species and cultivar

were defined (Table 1).

Each treatment (storage time) consisted of

10 replicate stems, and each storage trial was

repeated twice. Regression analysis was per-

formed on the data. Those stems infected

with fungal growth during storage were ar-

bitrarily assigned a vase life of zero, and

these values were included in the calculation

of mean vase life.

Proteaceae. Leucadendron ‘Silvan Red’,

Leucospermum ‘Firewheel’, and Protea cy-

naroides retained a vase life of at least 7 days

after 21 days of storage (Figs. 1 and 2). The

vase life of ‘Silvan Red’ had decreased by

only 11% (25 days compared with 28 days

in unstored controls) after 28 days of storage

Fig. 4. Fitted curves representing changes in vase

life in Verticordia spp. after dry storage at 1C.

1) V grandiflora (o); Y = 13.67 + 0.1049(X)

– 0 . 0 1 4 9 9 ( X

2

); Adj. R

2

=   9 2 . 9 .  S E   =

0.0587(X); 0.0016(X

2

). 2) V. nitens ( 

t );

Y =6.503 – 02012(X); Adj R

2 

= 72.0. 

SE

= 0.0178(X). 3) V monadelpha 

(◊). 

N o

regression equation. 4) V. pulmosa (A). No

regression equation. Where Y = vase life (days);

X = storage time (days).

Fig. 2.

Fitted curve representing change in vase

life in Leucadendron ‘Silvan Red’ after dry

s t o r a g e   a t   1 C .   Y   =   2 7 . 7 2   +   0 . 1 5 6 X   –

0 . 0 0 6 2 6 X

2

, Adj. R

2 

= 25.2. 

SE 

= 0.182X

2

,

0.00321X

2

. Where Y = vase life (days); X =

storage time (days).

(Fig. 2), and storage was therefore continued

for an additional 21 days. ‘Silvan Red’

maintained a commercially acceptable vase

life of 19 days even after 49 days of storage

(Fig. 2).

Poststorage vase life of Leucospermum

cordifolium declined rapidly after 14 days of

storage, mainly due to fungal infection (data

not shown). A more effective anti-fungal

treatment than we used probably would dra-

matically improve poststorage vase life in

this flower. Preliminary trials with L. cor-

diforium indicated that stems not infected with

fungal rot during storage had a vase life of

at least 7 days after 21 days of storage.

Cold storage-induced leaf blackening after

14 days of storage in P. neriifolia resulted

in a short poststorage vase life. Storage-in-

duced leaf blackening was not observed in

P. cynaroides.

Australian native cut flowers. Generally,

Australian native cut flower species stored

in these trials did not withstand the rigors of

dry storage as well as members of the Pro-

teaceae family (Figs. 3,4, and 5). However,

vase life in Thryptomene calycina and Tel-

opea speciosissima did not change signifi-

cantly after 21 days of storage (11 and 

7

Fig. 5. Fitted curves representing vase life in

kangaroo paw cultivars after dry storage at 1C.

1) ‘Gold Fever’ ( r ); Y = 13.3 – 0.578X +

0 . 0 0 6 5 9 X

2

. Adj. R

2 

= 83.5. 

SE 

= 0.0757X;

0.00208X

2

. 2)A. pulcherrimus ( 

t ); Y = 12.17

– 0.521X + 0.0059X

2

. Adj. R

2 

= 72.0. S E

= 0.0941X; 0.0826X

2

. 3) ‘Bush Harmony (0);

Y = 6.45 – 0.01X – 0.0042X

2

. Adj. R

2 

=

69.5. SE = 0.0498X; 0.00138x2.4) ‘Bush Haze’

(∆); 

Y = 7.1 – 0.1726X; Adj. R

2 

= 80.8.

SE = 0.012X. 5) ‘Ruby Delight  '    ); Y = 6.53

– 0.162X; Adj. R

2 

= 73.6. 

SE 

= 0.014X.

Where Y = vase life (days); X = storage time

(days).

Fig. 3.

Fitted curves representing changes in vase

life in selected Australian native cut flowers after

dry storage at 1C. 1) T. speciosissima ( r );

Y = 8.273 + 0.1744X – 0.00566X

2

. Adj.

R

2 

= 8.3. 

SE 

= 0.0847X; 0.00234X

2

. 2) T.

calycina ( 

t ); Y = 6.622 + 0.1341X –

0 . 0 0 4 8 2 X

2

. Adj. R

2 

= 19.0. 

SE 

= 0.0552X;

0.00153X. 3) C. uncinatum ‘Alba’ 

(◊); 

Y =

8.847 – 0.4657X + 0.00756x2. Adj. R

2 

=

81.7. SE = 0.0489X; 0.00135X

2

. 4) C. uncin–

atum ‘Purple Pride’ ( 

∆  

);Y = 7.8 – 0.4582X

+ 0.0069X

2

. Adj. R

2 

= 83.8. 

SE 

= 0.0478X,

0.00132X

2

. Where Y = vase life (days); X =

storage time (days).

days, respectively; Fig. ,3).

Verticordia grandiflora maintained a vase

life of 10 days after 21 days of storage (Fig.

4), after which vase life declined severely,

whereas the vase life of all other species of

Verticordia declined significantly after 14 days

of storage. No regression analysis was per-

formed on V. monadelpha and V. plumosa

as no stems survived after 14 days of stor-

age.

Significant floral abscission occurred in T.

calycina after 28 days of storage 

(≈15% 

to

20% of flowers). As there was no further

abscission during vase life assessment, these

stems were rated in a similar manner as con-

trol stems. Observations during preliminary

trials indicated that abscission became a ma-

jor problem during storage only when flow-

ers are harvested late in the season and in

full flower.

The vase life of stored T. speciosissima

was 8 days after 35 days of storage, similar

to the vase life of unstored control stems

(Fig. 3). Faragher (1986) reported that war-

atah vase life was reduced by 50% (from 6

to 3 days) if stems were stored at 4C, or if

flowers were stored unwrapped, indicating

the importance of low temperature (1C) and

the need to maintain flower hydration during

storage with adequate wrapping.

Quality in both C. uncinatum ‘Alba’ and

‘Purple Pride’ declined rapidly after 14 days

of storage (Fig. 3). Stems of C. uncinatum

were stored with a similar reduction in vase

life by Seaton and Joyce (1989). C. uncin-

atum suffered from fungal attack (identified

as Botrytis cinerea Pers.) in these trials, de-

spite a prestorage spray with 1 g iprodione/

liter, resulting in poor poststorage vase life.

Fungal infection was also prevalent in all

Verticordia spp. and kangaroo paw cultivars

after 21 days of storage. When present, it

effectively ended vase life immediately after

storage. The Veticordia spp. were not treated

with an antifungal agent before air transport

from Western Australia to Victoria, and con-

ditions during transit (high temperature, high

1396

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relative humidity) possibly were conducive

to fungal attack. Subsequent spraying with

1 g iprodione/liter was not sufficient to pre-

vent further fungal infection.

The evaluation of other anti-fungal agents

and spraying/dipping techniques has estab-

lished the anti-fungal potential of a mixture

of 1 g iprodione/liter and 1 g mancozeb/liter

(wettable powder, 80% a.i.; commercial

name: Mancozeb, suggested by D. Joyce;

data not shown). An effective anti-fungal

treatment that can be applied immediately

after harvest to improve the storage perform-

ance of C. uncinatum and Verticordia spp.

possibly will be developed.

Kangaroo paw cultivars with a long con-

trol vase life (Anigozanthos pulcherrimus and

the cultivar Bush Fever) suffered a substan-

tial reduction in vase life after 14 days of

storage (Fig. 5), leaving all kangaroo paw

cultivars with a vase life of <7 days after

14 days of storage. Seaton and Joyce (1989)

reported a dramatic decrease in vase life when

Anigozanthos rufus cut flowers were stored

for 2 weeks at 0C. Vase life significantly

increased in unstored kangaroo paws pulsed

with sucrose solutions of up to 30% (Carter

et al., 1989; Manning et al., 1989), and it

is possible that pre- and poststorage treat-

ment with a sucrose solution might extend

vase life significantly.

The vase lives cited in this study represent

a minimum value. Further improvements of

this storage protocol, including more ad-

vanced packaging techniques and the use of

solutions containing a germicide and sucrose

in the precooling and rehydration phases,

should improve the length of storage possi-

ble and the condition of flowers after stor-

age.

Our results suggest that Leucospermum

‘Firewheel’, Protea cynaroides, Leucaden-

dron ‘Silvan Red’, Thryptomene calycina,

Telopea speciosissima , and Verticordia

grandiflora can be stored for at least 21 days

and retain a commercially acceptable vase

life of at least 7 days. Vase life of stored

Leucospermum cordifolium, Chamelaucium

uncinatum ‘Alba’ and ‘Purple Pride’, Ver-

ticordia monadelpha, Verticordia  plumosa,

Verticordia nitens, Anigozanthos pulcherri-

mus, and the Anigozanthos cultivars Ruby

Delight, Bush Harmony, Bush Haze, and

Gold Fever declined significantly compared

with unstored controls. Australian native

species were susceptible to fungal attack

during storage. Effective anti-fungal treat-

ments may extend the storage period and vase

life of these species.

Literature Cited

Carter, E.M., D.C. Joyce, and T.J. Enright. 1989.

Pulsing native Australian cut flowers with sugar.

Proc. Conf. Production and Mktg. Austral. Flora,

13-14 July 1989, Univ. of Western Australia,

Perth.

Faragher, J.D. 1986. Effects of cold storage meth-

ods on vase life and physiology of cut waratah

inflorescences (Telopea speciosissima, Protea-

ceae). Scientia Hort. 29:163-171.

Fischer, C. 1952. Long-term holding of cut flow-

ers. Proc. Amer. Soc. Hort. Sci. 61:585-592.

Goszczynska, D.M. and R.M. Rudnicki. 1988.

Storage of cut flowers. Hort. Rev. 10:35-64.

Haasbroek, F.J., G.G. Rousseau, and J.F. de Vil-

liers 1973. Effect of gamma-rays on cut blooms

of Protea compacta R. Br., Protea longiflora

Lamarck and Leucospermum cordfolium Sal-

isb. ex Knight. Agroplantae 5:33-42.

Hardenburg, R.E., A.E. Watada, and C.Y. Wang.

1986. The commercial storage of fruits, vege-

tabls, and florist and nursery stocks. U.S. Dept.

Agr., Agr. Hdbk. 66.

Hauge, A., W. Bryant, and A. Laurie. 1947.

Packaging of cut flowers. Proc. Amer. Soc. Hort.

Sci. 49:427-432.

Ireland, J.P., J.T. Meynhardt, and J.M. Strauss.

1967. When Proteas become sailors-treatment

before shipping. Farming in South Africa: Dept.

Agr. Tech. Serv., Pretoria, S. Africa, Sept. 1967.

p. 33-35.

Joyce, D.C. 1988. Postharvest characteristics of

Geraldton Waxflowers. J. Amer. Soc. Hort. Sci.

13:738-742.

Manning, L.E., D.C. Joyce, and B.B. Lamont.

1989. Postharvest handling of kangaroo paws.

Proc. Conf. Production and Mktg. Austral. Flora,

13-14 July 1989, Univ. of Western Australia,

Perth.

Meynhardt, J.T. 1976. Proteas-picking and han-

dling. Farming in South Africa; Flower, Or-

namental Shrubs and Trees Series no. B5/1976

Dept. Agr. Tech. Serv., Pretoria, S. Africa.

Neff, M.S. 1939. Problems in the storage of cut

carnations. Plant Physiol. 14:271-284.

Seaton, K.A. and D.C. Joyce. 1989. Cold storage

of Geraldton Wax, kangaroo paw and Banksia.

Proc. 5th Austral. Agron. Conf.. Sept. 1989.

Univ. of Western Australia, Perth. p.532.

Thornton, N.C. 1930. The use of CO, for pro-

longing the life of cut flowers with special ref-

erence to roses. Amer. J. Bot. 17:614-626.

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