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Structural and geometrical analysis of follicles. (A) Micro-CT images of follicles in the longitudinal view: B. prionotes follicles show a porous exocarp in contrast to the other two species (this follicle aborted both seeds). A highly porous separator can be identified in all three species. (B) Schematic drawing based on longitudinal sections of follicles from all three species (top to bottom: B. prionotes, B. serrata, B. candolleana) showing the differences in size, geometry and embedment of all follicles and their components (valves in blue, seed separator in grey, seeds in white/ wings not displayed, embedment in dark grey). Orange area indicates areas with direct exposure to flames. Sometimes only one (as seen in B. candolleana here) or no seed is developed. All scale bars: 1 cm.
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Wildfires are a natural component in many terrestrial ecosystems and often play a crucial role in maintaining biodiversity, particularly in the fire-prone regions of Australia. A prime example of plants that are able to persist in these regions is the genus Banksia. Most Banksia species that occur in fire-prone regions produce woody seed pods (foll...
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... Thunderstorms are also associated with lightning strikes and these can lead to fires. Banksia are fire-adapted and most species that occur in fire-prone regions produce woody seed pods (follicles), which open during or soon after fire to release seeds into the postfire environment (Huss et al., 2019). ...
Banksia L.f., an iconic genus of the Proteaceae, is endemic to Australia, with its highest species richness and phylogenetic diversity (PD) in southwestern Western Australia. Analysis of the phylogenetic component of richness and endemism uncovered important patterns of Banksia evolutionary history that are not seen at the species level. We found that Banksia is significantly phylogenetically clustered in this region, likely due to recent evolutionary radiations. We also found significant concentrations of phylogenetic endemism in this region, both neoendemism (short, range‐restricted evolutionary branches) and paleoendemism (long, range‐restricted evolutionary branches). There is a striking northwest to southeast divide in phyloturnover in southwestern Western Australia. The majority of the variation in turnover patterns can be explained by environmental factors, with climate representing the largest covariate. This study adds to the growing body of evidence that indicates the importance of integrating phylogenetic and biodiversity data to inform conservation planning.
... 21 recorded higher concentrations of total phenolic and tannin in resistant species compared with those thermosensitive. Additionally, phenolics, mainly tannins, have low thermal conductivity [22][23][24] , which could have important roles during a fire event. ...
... Moreover, proanthocyanidins and flavan-3-ol monomers play critical ecological functions in environments with recurrent fires due to their excellent antioxidant capacity, resulting from their numerous hydroxyl groups 75,76 . Thus, we can assume that the prior presence of these compounds acted as a protective barrier against heat transfer during fires [22][23][24] . ...
We conducted a study on the effects of fire on Rhamnidium elaeocarpum, a widely distributed woody species found in the Pantanal wetlands, using LC–MS metabolomics, total phenolic and tannin content analysis, and thermogravimetric behavior. We sampled individuals from four groups: No Fire, Fire 2019, Fire 2020, and APD 20 (individuals whose aerial parts had died during the 2020 fire event). We found that recent fires had no significant impact on the species' phenolic metabolism except for those in the fourth group. These specimens showed a decline in secondary metabolites due to leaching. The high levels of phenolics in R. elaeocarpum suggest that this species has a biochemical tolerance to the stress caused by seasonal fires. Metabolomic profiling revealed the presence of proanthocyanidin oligomers, which protect against oxidative stress and post-fire environmental disturbances. However, the passage of fire also led to a high incidence of toxic karwinaphthopyranone derivatives, which could be a concern for the species' medicinal use. Finally, the thermogravimetric analysis showed that the species is thermotolerant, with an intrinsic relationship between the secondary compounds and thermotolerance. Our research has deepened the comprehension of how fire affects the metabolic processes of woody plants. The challenge now lies in determining if the identified chemical changes are adaptive characteristics that evolved over time or merely transient responses to external environmental stimuli.
... ericifolia is predominantly found in coastal heathland on shallow sandstone in the Sydney bioregion [56]. It relies on the release of seeds following plant death from fire for the production of the next generation of individuals [57]. The plants cannot resprout post-fire and rely on seeds for regeneration. ...
Seed fungal endophytes play a crucial role in assisting the overall health and success of their host plant; however, little is known about the factors that influence the diversity and composition of these endophytes, particularly with respect to how they change over time and within urban environments. Using culturing techniques, morphological analyses, and Sanger sequencing, we identified the culturable seed fungal endophytes of Banksia ericifolia at two urban and two natural sites in Sydney, New South Wales, Australia. A total of 27 Operational Taxonomic Units were obtained from 1200 seeds. Older cones were found to contain, on average, more colonised endophytes than younger cones. Species richness was also significantly influenced by cone age, with older cones being more speciose. Between urban and natural sites, the overall community composition did not change, although species richness and diversity were greatest at urban sites. Understanding how these endophytes vary in time and space may help provide an insight into the transmission pathways used and the potential role they play within the development and survival of the seed. This knowledge may also be crucial for restoration purposes, especially regarding the need to consider endophyte viability in ex situ seed collection and storage in seed-banking practices.
... Da Silva et al. (2021) recorded higher concentrations of total phenolic and tannin in resistant species compared to thermosensitive ones. Additionally, phenolics, mainly tannins, have low thermal conductivity (Celzard et al. 2011;Huss et al. 2019;Tributsch and Fiechter 2008), which could have important roles during a re event. ...
... Moreover, proanthocyanidins and avan-3-ol monomers play critical ecological functions in environments with recurrent res due to their excellent antioxidant capacity, resulting from their numerous hydroxyl groups (Dumanovié et al., 2021;Hasanuzzaman et al. 2020;Saini et al. 2018). Thus, we can assume that the prior presence of these compounds acted as a protective barrier against heat transfer during res (Celzard et al. 2011;Huss et al. 2019;Tributsch and Fiechter 2008). ...
We conducted a study on the effects of fire on Rhamnidium elaeocarpum , a widely distributed woody species found in the Pantanal wetlands, using LC-MS metabolomics, total phenolic and tannin content analysis, and thermogravimetric behavior. We sampled individuals from four different groups and found that recent fires had no significant impact on the species' phenolic metabolism, except for those specimens whose aerial parts had died during the 2020 megafire, which showed a compound decline due to leaching. The high levels of phenolics in R. elaeocarpum suggest that the species has a biochemical tolerance to the stress caused by seasonal fires. Metabolomic profiling revealed the presence of proanthocyanidin oligomers, which protect against oxidative stress and post-fire environmental disturbances. However, the passage of fire also led to a high incidence of toxic karwinaphthopyranone derivatives, which could be a concern for the species' medicinal use. Finally, the thermogravimetric analysis showed that the species is thermotolerant, with an intrinsic relationship between the secondary compounds and thermotolerance. Our study enhances our understanding of the impact of fire on woody species' metabolism, although distinguishing whether chemical traits are an adaptive feature or a response to surrounding environmental factors is challenging.
... Fire plays a major role in the ecology of seed release in many Banksia species (Lamont et al. 2007;Huss et al. 2019). Queensland populations of B. conferta are reportedly serotinous (George 1981), releasing seeds from the canopy only after a fire event. ...
Context and aim: Stands of the critically endangered Banksia conferta in north-eastern New South Wales show low recruitment and were examined to elucidate whether pollinator absence or fire history best explained this. Methods: Motion-detection cameras were deployed at three sites to identify potential pollinators, and age structure within stands and past follicle production were assessed through tree measurements and follicle counts. Key results: In total, 691 fauna-triggered image sequences were recorded between June and December 2019. Six mammal and 10 bird species were detected, but only 10 of these were observed probing inflorescences. White-cheeked Honeyeater and Sugar Glider combined comprised 66% of all fauna interactions, and of all 400 Banksia probes, 45% were from White-cheeked Honeyeaters and 18% were by Sugar Gliders. Different size structures of B. conferta were evident at each site, consistent with older and younger populations post-fire. Significantly more Banksia individuals (5×) were present at the younger site, likely governing pollinator composition through interspecific competition within pollinator guilds, and past follicle production was also greater here.
Conclusions: Pollinator absence is not the cause of low recruitment in this population, and current stand structure and follicle production reflect past fire history. The three sites differed in their dominant fauna foragers, suggesting that B. conferta is a pollinator-generalist. Birds appear to operate as the key pollinating species during the day but are replaced by small mammals at night. Follicle production is higher in younger post-fire plants. Implications: The absence of fire from older populations for over 55 years is of concern, and population decline seems likely without fire intervention.
... For seeds stored in serotinous woody fruits or cones in plant canopies, the structures covering the seeds insulate them from lethal temperatures (Hanley and Lamont, 2000;Huss et al., 2019;Lamont, 2020), which can exceed 450 C (Bradstock and Myerscough, 1981). However, modeling of the impacts of high severity crown fires in jack pine (Pinus banksiana) and lodgepole pine (P. ...
Climate change is increasing the frequency, intensity, and size of fire events due to longer and more sustained droughts and heatwaves. The potential for regeneration of plants from seeds in fire-prone regions that will be impacted by climate change is due to (1) changes in the environmental conditions experienced by parent plants, seeds, and seedlings, and (2) changes in the fire regime. One of the clearest projections of the impacts of climate change is the switching of fire regimes away from historic patterns, which is likely to cause changes in species abundance and persistence and associated changes in community composition. In the worst scenario, shifts in fire regime will increase the risk of local extinction. Further understanding the response of species to climate-driven shifts, particularly in the context of shorter intervals between fires, will help us predict which species will persist and which may decline in number of individuals under climate change and provide some guidance of actions required for conservation in fire-prone ecosystems.
... prionotes and B. sessilis) commonly maintain canopy seed banks via the storage of seeds within woody fruits (serotiny; Lamont, 1991). Serotiny provides seeds stored within the woody fruits increased protection from fire temperatures, as well as from ambient moisture Huss et al., 2019), with seeds typically released from the fruits after fire . However, within our study system of the Banksia woodlands of the Perth region, both Banksia species are weakly serotinous and release seeds in the absence of fire -annually and shortly after maturationinto the soil seed bank (Cowling and Lamont, 1985). ...
Changes in fire regimes due to climate change and fire management practices are affecting the timing, length, and distribution of vegetation fires throughout the year. Plant species responses and tolerances to fire differ from season to season and are influenced by species-specific phenological processes. The ability of seeds to tolerate extreme temperatures associated with fire is one of these processes, with survival linked to seed moisture content at the time of exposure. As fire is more often occurring outside historic dry fire seasons, the probability of fire occurring when seeds are hydrated may also be increasing. In this study, we set out to understand the seasonal dynamics of seed hydration for seeds of Banksia woodland species, and how certain seed traits interact with environmental conditions to influence survival of high temperatures associated with fire. We measured the moisture content of seeds buried to 2 cm in the soil seed bank for four common native species and one invasive species on a weekly basis throughout 2017, along with soil moisture content and environmental correlates. We determined water sorption isotherms at 20°C for seeds of each species and used these functions to model weekly variation in seed water activity and predict when seeds are most sensitive to soil heating. Using Generalised additive models (GAMs), we were able to describe approximately 67% of the weekly variance in seed water activity and explored differences in seed hydration dynamics between species. Seed water activity was sufficiently high (i.e., ≥ 0.85 aw) so as to have created an increased risk of mortality if a fire had occurred during an almost continuous period between May and November in the study period (i.e., 2017). There were brief windows when seeds may have been in a dry state during early winter and late spring, and also when they may have been in a wet state during summer and late autumn. These data, and the associated analyses, provide an opportunity to develop approaches to minimize seed mortality during fire and maximize the seed bank response.
... Some plant species from fire-prone environments have specialized structures in their diaspores that could provide higher or limited protection against fires and high temperatures. These plants generally have woody fruits, thick seed coats, and long viability when stored in the soil seed bank, due to the effects of soil insulation and seeds' tissue protection (Bicalho et al., 2016;Huss et al., 2019). ...
... Herein, the endocarp helps to avoid cell membrane damage and protect the seed against high temperatures while keeping embryos with high viability and vigor after its exposure to 80°C for up to 180 seconds. The same effect regarding viability maintenance was observed in Banksia seeds protected by lignified structures (follicles) (Huss et al., 2019) and in macaúba palm embryos, exposed to fire before fruit dispersion (Bicalho et al., 2016). Our results suggest that the temporal dynamics of fruit dispersion and seed bank formation with the exposition to fire in natural environments might be decisive to the maintenance of embryo viability in macaúba palm. ...
Acrocomia aculeata (macaúba palm) is a promising oilseed species for bioenergy, found in fire-prone areas. However, the effects of fire on the viability of macaúba palm embryos in fruits and during seed bank formation in the soil are unknown. This study aimed to evaluate the viability of A. aculeata embryos in response to fire and high temperatures. In the first assay, macaúba palm fruits and pyrenes were arranged on the soil surface and buried at 2 cm following fire exposition. Control treatment, buried fruits, and pyrenes showed no differences and presented embryos with high viability, contrasting with fruits and pyrenes in the soil surface. In a second assay, pyrenes and seeds were exposed to 80° C in a water bath for 30, 60, 180, and 300 seconds. The exposition of seeds to 80°C for 30 seconds, resulted in low viability (10%) and absence of vigorous embryos. Pyrenes presented greater viability (74%) and vigor (46%) after 60 seconds of exposure to thermal stress. Viable embryos were found in pyrenes exposed up to 180 seconds in high temperature. The soil and the structure of the macaúba’s palm endocarp play an important role in the tolerance of its embryos to fire and heat.
... For example, from the experience of the research I have been conducting on shape changing, you end up using these different tools in widely different disciplines. For example, when we explored macroscopic shape changes of the ice plant or the Banksia seed pods, we used the same computational tools that we use to describe the behavior of synthetic materials [Guiducci et al. 2015;Harrington et al. 2011, footnote 6;Huss et al. 2019]. Furthermore, the description of the reaction-diffusion equations mentioned earlier works well in chemistry, but it can also be used in biology. ...
... JD: In order to answer this question, it is necessary to describe the two directions that interest me. On the one hand, I am into changes in environmental conditionsand I suppose in this respect this is inspired by these structures that you can see in plants that actuate, like a pine cone (see Fig. 2), wheat awns, the ice plant, or the Banksia seed pods [Dunlop, Weinkamer, and Fratzl 2011;Harrington et al. 2011;Huss et al. 2019]. ...
The chapter is open access and can be downloaded for free at the editor house: https://www.degruyter.com/document/doi/10.1515/9783110562064/html
... The production of phenolic compounds in bark is associated with protection against herbivore attacks (Boeckler et al., 2011;Mason et al., 2017;Tozin et al., 2017) and abiotic factors, such as high or low temperatures and water deficit (Abreu and Mazzafera, 2005;Albergaria et al., 2020;Mechri et al., 2020). In addition to serving a defensive role, phenols and tannins also have a low thermal conductivity (Tributsch and Fiechter, 2008;Celzard et al., 2011;Huss et al., 2019). In some species of fire-prone environments, the leaf levels of phenolic compounds increase after fire events (Bardoni et al., 2011;Lavoir et al., 2013), and such levels are used as bioindicators of fire occurrence (Cannac et al., 2009;Santacruz-García et al., 2021). ...
Fire is common in seasonally dry areas in many parts of the world, and its effects on vegetation in these areas have been well studied. In riparian forests of the Pantanal, where fuel accumulation (dead plants) in the dry season can be a substantial driver of fire occurrence, little is known about the role of bark traits to fire protection in woody plants. Herein we evaluated some physical, chemical and anatomical bark traits to determine if they are associated with fire tolerance in tree riparian species of the Pantanal. To accomplish this, we selected three fire-sensitive species and seven fire-tolerant species in riparian forest of the Paraguay River. Bark samples were analyzed for relative total, outer and inner bark thickness, bark density, concentration of phenolic compounds and tannins, thermogravimetric behavior and their anatomical structure. We observed higher concentration of phenol and tannins and higher percentage of sclerenchyma in bark from fire-tolerant species than fire-sensitive species. Bark of fire-tolerant species also showed more sclerenchyma cells near vascular cambium and higher temperatures of thermal decomposition. In contrast, relative total, outer and inner bark thickness, and bark density did not differ between species groups. The high concentration of phenol and tannins, combined with higher percentage of sclerenchyma in secondary phloem, appear as the major bark traits that could mitigate fire damage in species from riparian forest of the Brazilian Pantanal.
