The Proteaceae comprise about 1000 species of trees and shrubs within more than 50 genera. The most useful species is Macadamia ternifolia F. Muell., Macadamia or Queensland nut, which provides an edible nut. The fruits are nuts, drupes, capsules or follicles. Seed storage behaviour is uncertain. Although many species show orthodox seed storage behaviour - for example, Embothrium coccineum is maintained in the long-term seed store at the Wakehurst Place Gene Bank - recalcitrant seed storage behaviour has been suggested, though not confirmed, in the Macadamia nut.
SEED DORMANCY AND GERMINATION
Advice on suitable germination test procedures and dormancy-breaking treatments is limited (Table 60.1). In developing appropriate techniques, RBG Kew Wakehurst Place suggests a useful first step is to test a sample of the seeds in an alternating temperature regime of 33°/19°C (12h/12h) with light applied for 12h/d during the period spent at the upper temperature.
TABLE 60.1 Summary of germination test recommendations for species within the Proteaceae
|
Species and Authority |
Substrate |
Temperature |
Duration |
Additional directions |
Source |
|
Gevuina avellana |
|
|
21d |
pre-soak, 24h, then warm stratification |
Riley |
|
Grevillea robusta Cunn. ex R. Br.
|
TP |
20°/30°C |
28d |
potassium nitrate, pre-chill |
ISTA |
|
TP; BP |
20°/30°C |
21d |
light |
AOSA |
|
|
Macadamia spp. |
|
|
30d |
pre-soak, 24h |
Riley |
