Seed storage, germination and establishment in southwestern Australia (original) (raw)

Seed release and dispersal in southwestern Australia

The southwestern Australian flora is unique in the world, not only for its biodiversity and endemism, but also for its functional biodiversity. It also contains the world's most nutrient-impoverished soils, has a prolonged-summer period and the vegetation is extremely fire-prone. These conditions have engendered an array of survival adaptations that have evolved in these harsh conditions across a diverse range of species. It is well recognised that the southwest flora has the toughest and most spiny vegetation of the world, the greatest number of species that store their seeds in woody fruits, and the most specialised means of obtaining limited soil nutrients and water. This book focuses on the survival mechanisms, adaptations and ecology of the unique Southwest Australian flora (restricted here to flowering plants). The book begins with an examination of how the flora has evolved into the present forms. It describes further in detail the adaptive responses of the flora to the m...

Evolution and diversity of the southwestern Australian flora

Fire adaptations in the southwestern Australian flora

Drought responses in the southwestern Australian flora

Pollination strategies in southwestern Australia

Distinguishing between persistence and dormancy in soil seed banks of three shrub species from fire-prone southeastern Australia

Journal of Vegetation Science, 2007

Is primary dormancy required for seed bank persistence of Leucopogon species? How does the distinction between dormancy and persistence affect our understanding of seed bank dynamics in fire-prone regions? Location: Sclerophyllous plant communities, Sydney region, southeastern Australia. Methods: Seed bank longevity of three morphophysiologically dormant species was ascertained using seed burial trials. Seeds of each species were buried in situ in replicate mesh bags and retrieved annually over three years. Laboratory germination trials and embryo growth measurements over time were used to establish in which order each component of dormancy was overcome, and whether seed banks persisted after the loss of primary dormancy. Results: All species had long-term persistent seed banks, with estimated half-lives between 3.5 and 5.5 years. Physiological dormancy was broken by stratification prior to embryo growth, during the first year of burial. Seeds were able to germinate after retrieval, in light and at warm temperatures. Only low levels of germination occurred in situ over three years of burial, and did not increase over time. During germination trials, embryos remained underdeveloped unless seeds germinated, indicating that seeds were committed to germination once embryo growth was initiated. Conclusions: Long-lived seed banks are an important trait of plants from fire-prone communities, but cues observed to promote germination in situ are not necessarily the ones that break dormancy. A failure to distinguish between these two factors can divert attention away from mechanisms actually controlling dormancy and seed bank dynamics.

Seed bank patterns in Restionaceae and Epacridaceae after wildfire in kwongan in southwestern Australia

Journal of Vegetation Science, 1994

Abstract. Post-fire seed germination, seedling mortality and seed banks were investigated in scrub-heath (kwongan) in SW Australia. Study species included herbaceous and woody, obligate seeders and resprouters in two non-bradysporous but significant plant families (Restionaceae and Epacridaceae). In all species, seedlings were recruited only in the first autumn-spring after fire and occurred in similar densities as the estimated germinable annual seed input. Seedlings were absent from unburnt vegetation. Although most species retained some residual seeds after fire, tests (excised embryo culture) indicated that a negligible number of seeds were germinable. Regardless of fire response or species, there appeared to be a large loss of seeds each year and in most cases, only a small proportion of the annual seed production was used in post-fire recovery of plants. Based on seedling: parent ratios, all species had the capacity to reconstitute parent densities from germinants in the first year after fire, but high seedling mortality and no further recruitment resulted in less seedlings than replacements for four resprouter Restionaceae and three Epacridaceae (all obligate seeders) at the end of the third year after fire.

Seed storage, germination and establishment in southwestern Australia (original) (raw)

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