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Ecological divergence and evolutionary transition of resprouting types in Banksia attenuata.

He T - Ecol Evol (2014)

Bottom Line: The fitness benefits associated with resprouting include a rapid return to adult growth, early flowering, and setting seed.A microsatellite allele has been shown to be associated with epicormic populations.It is concluded that the postfire resprouting type in B. attenuata is likely determined by the fire's characteristics.

View Article: PubMed Central - PubMed

Affiliation: Department of Environment and Agriculture, Curtin University PO Box U1987, Perth, WA, 6845, Australia.

ABSTRACT
Resprouting is a key functional trait that allows plants to survive diverse disturbances. The fitness benefits associated with resprouting include a rapid return to adult growth, early flowering, and setting seed. The resprouting responses observed following fire are varied, as are the ecological outcomes. Understanding the ecological divergence and evolutionary pathways of different resprouting types and how the environment and genetics interact to drive such morphological evolution represents an important, but under-studied, topic. In the present study, microsatellite markers and microevolutionary approaches were used to better understand: (1) whether genetic differentiation is related to morphological divergence among resprouting types and if so, whether there are any specific genetic variations associated with morphological divergence and (2) the evolutionary pathway of the transitions between two resprouting types in Banksia attenuata (epicormic resprouting from aerial stems or branch; resprouting from a underground lignotuber). The results revealed an association between population genetic differentiation and the morphological divergence of postfire resprouting types in B. attenuata. A microsatellite allele has been shown to be associated with epicormic populations. Approximate Bayesian Computation analysis revealed a likely evolutionary transition from epicormic to lignotuberous resprouting in B. attenuata. It is concluded that the postfire resprouting type in B. attenuata is likely determined by the fire's characteristics. The differentiated expression of postfire resprouting types in different environments is likely a consequence of local genetic adaptation. The capacity to shift the postfire resprouting type to adapt to diverse fire regimes is most likely the key factor explaining why B. attenuata is the most widespread member of the Banksia genus.

No MeSH data available.


The distinctive morphologies of the two postfire resprouting types of Banksia attenuata. (A) Tree form (8.6 m in the figure); (B) epicormic resprouting (1 year after fire); (C) shrub form (1.8 m in the figure); (D) lignotuberous resprouting (1 year after fire).
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fig02: The distinctive morphologies of the two postfire resprouting types of Banksia attenuata. (A) Tree form (8.6 m in the figure); (B) epicormic resprouting (1 year after fire); (C) shrub form (1.8 m in the figure); (D) lignotuberous resprouting (1 year after fire).

Mentions: The examined populations of Banksia attenuata displayed clear morphological discontinuity across the species' range (Table 1, Fig. 1). The natural populations of B. attenuata in the northern part of its range are exclusively lignotuberous, with a lignotuber structure being observed in all individuals. The lignotuberous individuals are multistemmed, with short (less than 2.4 m), narrow stems (smaller than 26 cm in circumference at 50 cm above the ground) (Table 1, Figs. 1, 2). In contrast, no individuals in the southern populations were found to present a lignotuberous structure. The growth form of these individuals is trees up to 10.4 m tall with one, or rarely two main trunks emerging from the ground and a circumference of up to 134 cm at 50 cm above the ground (Table 1, Figs. 1, 2). The vegetation in the northern range is heath shrubland with a canopy height of less than 2.5 m, whereas the southern sand plains are usually covered by open forest dominated by species (such as B. attenuata) up to 10 m tall. The northern range is drier and hotter, and its plants show a shorter growth season compared to southern part (Table 1). Extensive field surveys over the area where the two types were suggested to overlap failed to locate any mixed populations.


Ecological divergence and evolutionary transition of resprouting types in Banksia attenuata.

He T - Ecol Evol (2014)

The distinctive morphologies of the two postfire resprouting types of Banksia attenuata. (A) Tree form (8.6 m in the figure); (B) epicormic resprouting (1 year after fire); (C) shrub form (1.8 m in the figure); (D) lignotuberous resprouting (1 year after fire).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222204&req=5

fig02: The distinctive morphologies of the two postfire resprouting types of Banksia attenuata. (A) Tree form (8.6 m in the figure); (B) epicormic resprouting (1 year after fire); (C) shrub form (1.8 m in the figure); (D) lignotuberous resprouting (1 year after fire).
Mentions: The examined populations of Banksia attenuata displayed clear morphological discontinuity across the species' range (Table 1, Fig. 1). The natural populations of B. attenuata in the northern part of its range are exclusively lignotuberous, with a lignotuber structure being observed in all individuals. The lignotuberous individuals are multistemmed, with short (less than 2.4 m), narrow stems (smaller than 26 cm in circumference at 50 cm above the ground) (Table 1, Figs. 1, 2). In contrast, no individuals in the southern populations were found to present a lignotuberous structure. The growth form of these individuals is trees up to 10.4 m tall with one, or rarely two main trunks emerging from the ground and a circumference of up to 134 cm at 50 cm above the ground (Table 1, Figs. 1, 2). The vegetation in the northern range is heath shrubland with a canopy height of less than 2.5 m, whereas the southern sand plains are usually covered by open forest dominated by species (such as B. attenuata) up to 10 m tall. The northern range is drier and hotter, and its plants show a shorter growth season compared to southern part (Table 1). Extensive field surveys over the area where the two types were suggested to overlap failed to locate any mixed populations.

Bottom Line: The fitness benefits associated with resprouting include a rapid return to adult growth, early flowering, and setting seed.A microsatellite allele has been shown to be associated with epicormic populations.It is concluded that the postfire resprouting type in B. attenuata is likely determined by the fire's characteristics.

View Article: PubMed Central - PubMed

Affiliation: Department of Environment and Agriculture, Curtin University PO Box U1987, Perth, WA, 6845, Australia.

ABSTRACT
Resprouting is a key functional trait that allows plants to survive diverse disturbances. The fitness benefits associated with resprouting include a rapid return to adult growth, early flowering, and setting seed. The resprouting responses observed following fire are varied, as are the ecological outcomes. Understanding the ecological divergence and evolutionary pathways of different resprouting types and how the environment and genetics interact to drive such morphological evolution represents an important, but under-studied, topic. In the present study, microsatellite markers and microevolutionary approaches were used to better understand: (1) whether genetic differentiation is related to morphological divergence among resprouting types and if so, whether there are any specific genetic variations associated with morphological divergence and (2) the evolutionary pathway of the transitions between two resprouting types in Banksia attenuata (epicormic resprouting from aerial stems or branch; resprouting from a underground lignotuber). The results revealed an association between population genetic differentiation and the morphological divergence of postfire resprouting types in B. attenuata. A microsatellite allele has been shown to be associated with epicormic populations. Approximate Bayesian Computation analysis revealed a likely evolutionary transition from epicormic to lignotuberous resprouting in B. attenuata. It is concluded that the postfire resprouting type in B. attenuata is likely determined by the fire's characteristics. The differentiated expression of postfire resprouting types in different environments is likely a consequence of local genetic adaptation. The capacity to shift the postfire resprouting type to adapt to diverse fire regimes is most likely the key factor explaining why B. attenuata is the most widespread member of the Banksia genus.

No MeSH data available.