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Seed dormancy and germination in the Australian baobab, Adansonia gregorii F. Muell.

Published online by Cambridge University Press:  01 December 2009

S.R. Turner*
Affiliation:
Kings Park and Botanic Garden, West Perth, WA6005, Australia Faculty of Health Sciences, School of Pharmacy, The University of Queensland, Brisbane, QLD4072, Australia
K.W. Dixon
Affiliation:
Kings Park and Botanic Garden, West Perth, WA6005, Australia Faculty of Natural and Agricultural Sciences, School of Plant Biology, The University of Western Australia, Crawley, WA6009, Australia
*
*Correspondence Fax: +61 9480 3641 E-mail: sturner@bgpa.wa.gov.au

Abstract

Seeds of the iconic Australian baobab Adansonia gregorii display physical dormancy (PY) and germinate readily once they become water permeable, a trait found in most other species in this genus. Highest germination (100%) was observed when seeds were placed in concentrated sulphuric acid (H2SO4) for 24 h, although exposure to H2SO4 for 6–12 h also resulted in >85% germination. Exposure to boiling water for 1–5 min was far less effective in promoting germination (0–23%), although a high number of seeds were water permeable (67–99%) following boiling water treatment. However, the majority of these water-permeable seeds appeared to have been injured by boiling water exposure. Germination at warmer temperatures (30 or 35°C) was found to be optimal (81–83% germination) and proceeded rapidly, with maximum germination occurring after incubation for only 8 d. In comparison, germination at 15–25°C resulted in 3–67% germination over a longer time frame (up to 20 d). While seeds of A. gregorii display PY they are unusually sensitive to dipping in boiling water and are therefore atypical when compared to most other Adansonia species.

Type
Short Communication
Copyright
Copyright © Cambridge University Press 2009

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