Variation in some floral, seed, and growth characteristics of Acacia harpophylla (Brigalow)

Coaldrake, J. E.

doi:10.1071/bt9710335

Cited by 16 publications

(6 citation statements)

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“…Acacia harpophylla and A. cambagei are well known to have non-dormant seeds that have a relatively short viability (Coaldrake, 1971; Reichman et al ., 2006). Johnson (1964) noted that this allows establishment after spasmodic rain which was then followed by hot, dry periods.…”

Section: Discussionmentioning

confidence: 99%

Markedly different patterns of imbibition in seeds of 48 Acacia species

2019

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The seeds of most Australian acacias have pronounced physical dormancy (PY). While fire and hot water (HW) treatments cause the lens to ‘pop’ almost instantaneously, for many Acacia species the increase in germination percentage can be gradual. If PY is broken instantly by HW treatment, why is germination often an extended process? Control and HW treatments were performed on seeds of 48 species of Acacia. Seeds were placed on a moist substrate and imbibition was assessed by frequently weighing individual seeds. In the two soft-seeded species all control seeds were fully imbibed within 6–24 h, while in hard-seeded species very few control seeds imbibed over several weeks. In 10 species over 50% of the HW-treated seeds imbibed within 30 h, but mostly the percentage of imbibed seeds gradually increased over several weeks. Some seeds in a replicate would imbibe early, while others would remain unimbibed for many days or weeks then, remarkably, become fully imbibed in less than 24 h. While HW treatment broke PY almost instantaneously, it appeared that in many Acacia species some other part of the testa slowed water from reaching the embryo. This process of having staggered imbibition may be a way of ensuring not all seeds in a population germinate after small rain events. Thus it appears the lens acts as a ‘fire gauge’ while some other part of the seed coat acts as a ‘rain gauge’.

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Section: Discussionmentioning

confidence: 99%

Markedly different patterns of imbibition in seeds of 48 Acacia species

2019

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“…Genecological differentiation of habit has also been demonstrated in several other Acacia species (e.g. Coaldrake 1971;Hannon and McMillan 1972;McMillan 1973;Farrell and Ashton 1978), so it is possible that this characteristic may be quite widespread in this cosmopolitan genus. Genecological differentiation of habit has not been reported in the other three genera, although some species of Banksia and Hakea do show phenotypic habit differentiation in the Sydney region (e.g.…”

Section: (A) and Site 4 (Site 5 For A Myrtifolia) (V)mentioning

confidence: 89%

Genetic Determination of Erect and Prostrate Growth Habit in Five Shrubs From Windswept Headlands in the Sydney Region

Auld¹,

Morrison²

1992

Aust. J. Bot.

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In the Sydney region, many plants from populations on windswept headlands have a more prostrate growth habit compared with plants from populations of the same species occurring away from the coast. To determine whether these different growth habits are genetically determined, plants from four populations of each of five species (Acacia rnyrtifolia, Acacia suaveolens, Banksia ericifolia, Casuarina distyla, Hakea teretifolia) were grown under uniform glasshouse conditions. Multivariate analyses of six morphological characteristics indicate that, for four of these species, the offspring are similar to their maternal parent; we thus conclude that the habit differences are genetically fixed in these populations. The same trend is apparent for C. distyla, although significant variation occurs in the offspring. Univariate analyses indicate that different characteristics reflect the habit differences in different species. For conservation biology, the implications of this intra-specific variation are that attempts should be made to conserve viable populations of all genetically isolated taxa within a species.

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“…The adaptation of the populations to its environment seems achieved by variable pinnules morphology where reduction in transpiring surfaces has compensated by an increase in number of pinnules. Although, these two traits are expected to be highly correlated but the inconsistency for pinnules number and size can be explained in the light of work reported by Coaldrake (1971), who demonstrated an independent pattern of differentiation even for correlated characters on account of the variability of each microsite that influenced inconsistently different traits. Therefore, an incoherent differentiation pattern can result even for associated characters.…”

Section: Discussionmentioning

confidence: 99%

Spatial pattern of variation in populations of Acacia nilotica in semi-arid environment

Mahmood

Ahmed

Hussain³

et al. 2005

Int. J. Environ. Sci. Technol.

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Variability among populations was analyzed in five provenances of Acacia nilotica from spatially variable habitats. Populations of A. nilotica developed in response to their habitat conditions. The level of variability was significantly high among the populations. Phenotypic variability was extremely high for leaf and stipular spine characteristics. The nature of morphological variability for vegetative traits appeared environmentally controlled. The differentiation of leaf and stipular spine expression seems to have an adaptive significance for the species in terms of water economy. Although, seed and pod characteristics are genetically controlled showing a lower proportion of variability but these traits supported r and k-selection that may allow the species to survive under a wide array of contrasting habitats. The study suggested that populations of A. nilotica are differentiated in relation to the heterogeneity of environment. These populations became adapted to their habitat through the variability of morphological expressions. The morphologically differentiated populations of the species had allowed them to maintain themselves in a wide array of environmental situations enabling A. nilotica to occupy ample ecological ranges.

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Variation in some floral, seed, and growth characteristics of Acacia harpophylla (Brigalow)

Cited by 16 publications

References 0 publications

Markedly different patterns of imbibition in seeds of 48 Acacia species

Markedly different patterns of imbibition in seeds of 48 Acacia species

Genetic Determination of Erect and Prostrate Growth Habit in Five Shrubs From Windswept Headlands in the Sydney Region

Spatial pattern of variation in populations of Acacia nilotica in semi-arid environment

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