The Lecythidaceae comprise over 230 species of trees within 18 genera which provide edible nuts (e.g. Lecythis zabucajo Aubl., paradise nut). The fruits have hard, thick walls and generally contain about 12 to 24 nuts. Seed storage characteristics are unknown.
SEED DORMANCY AND GERMINATION
The shells of the nuts vary from leathery to woody and can act as a barrier to germination. Information is provided in this chapter for the genus Bertholletia only.
BERTHOLLETIA
|
B. excelsa HBK |
Brazil nut |
I. Evidence of dormancy
Seeds of B. excelsa can show considerable dormancy due to the hard seed coat (1,2) and are reported to take between 12 and 15 months to germinate (1).
II. Germination regimes for non-dormant seeds
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III. Unsuccessful dormancy-breaking treatments
Sodium hydroxide: pre-applied, 7,15h, 1.5, 3% (1); pre-applied, 18,24h, 5, 10% (1)
Scarification: mechanical, at striae (2)
IV. Partly-successful dormancy-breaking treatments
Pre-soak: 18,24h (1); 7d (2)
Scarification: mechanical, at micropyle end (2); mechanical, at striae and micropyle end (2); sulphuric acid, 25, 50%, 18,24h (1); sulphuric acid, 25%, 7h (1)
V. Successful dormancy-breaking treatments
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VI. Comment
Unfortunately we have not found any reports which describe precise environmental conditions suitable for germinating seeds of B. excelsa. It is suggested that the seeds be scarified by hand at the micropyle end and then tested for germination between moist rolled paper towels at a constant temperature of 30°C - although ultimately a more suitable alternating temperature regime may be found. A considerable germination test period may be necessary - see the first section.
VII. References
1. Barbosa, M.M.S. (1974). [Germination trials with Brazil nuts.] Boletim da Instituto Biologico da Bahia, 13, 100-106.
2. Pereira, L.A.F., Muller, C.H., Muller, A.A., Figueriedo, F.J.C. and Frazao, D.A.C. (1980). [Mechanical scarification and imbibition (effect) on germination of Brazil nuts.] Boletim de Pesquisa, Centro de Pesquisa Agropecuaria do Tropico Umido, 10, 13 pp. (From Seed Abstracts, 1983, 6, 1130.)
