Pyrogenic flowering

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Telopea speciosissima - popular flower in New South Wales Australia that utilizes pyrogenic flowering. Telopea speciosissima Ingar Falls crop.jpg
Telopea speciosissima - popular flower in New South Wales Australia that utilizes pyrogenic flowering.

Pyrogenic flowering is the fire-adapted trait in plants that is defined by an increase or a peak in flowering after a fire event. [1] Pyrogenic flowering allows for plants to persist in fire-prone environments. [2] [3] Pyrogenic flowering can be facultative, meaning the rate of flowering temporarily increases following burning, or obligate, meaning flowering only occurs post-fire. [3] There is high variation in the length of time between when a fire occurs and when pyrogenic flowering is triggered, and it is frequently species specific. Some pyrogenic flowering does not occur until up to a year post-fire [1] whereas in extreme cases some flowers can emerge just hours after fire disturbance. [4] Precise physiological triggers for pyrogenic flowering have not been heavily studied as is likely to vary between groups. Some suggested stimuli of pyrogenic flowering are the increase in light due to loss of canopy or competition, nutrient changes in the soil, or chemicals associated with fires acting as a trigger. [1] [5]

Contents

Pyrogenic flowering is likely to have first evolved in the Late Cretaceous period (146-66 million years ago) from a plant which already demonstrated post-fire re-sprouting ability, the trait evolved then more rapidly in the Cenozoic era. [2] This flowering adaptation can be found in plants across the world in the Americas, Australia, Europe, and Africa in fire-prone environments such as heathland and savannas. [2] Zirondi et al. found that nearly 66% of plants in the Cerrado tropical savanna of Brazil utilize some form of pyrogenic flowering as a reproductive strategy [5] highlighting how widespread this strategy can be in fire-prone environments.

The most well known species of plant that utilizes pyrogenic flowering strategies is Telopea speciosissima, commonly known as Waratah. It is the floral emblem of New South Wales in Australia, and is frequently used as a motif on insignia and official emblems. [6] Waratah has been successfully cultivated in many areas of the world, and hybridization of different plants have resulted in many different color varieties. [6]

Benefits

Doryanthes excelsa - facultative flowering plant native to Australia. Utilized in landscaping. Doryanthes excelsa (Gymea Lilly), Birrarung Marr, Melbourne, Victoria Australia (5129020223).jpg
Doryanthes excelsa - facultative flowering plant native to Australia. Utilized in landscaping.

Pyrogenic flowering confers many fitness benefits to plants in fire-prone habitats. Plants with pyrogenic flowering will flower at the same time after a fire, potentially increasing the rate of pollination and creating a seed-boom which satiates seed predators, positively affecting the overall germination rate. [3] The delayed recruitment of seeds seen in pyrogenic flowering may also allow the plants to avoid periods of high seed predation post-fire. [7] Flowering post fire may also be advantageous in allowing the plants to take advantage of new and plentiful resources post-fire, avoiding competition during non-fire periods. [3]

Ecology

Fire exclusion has resulted in a declining reproductive output, and thus population size, of some species of pyrogenic plants. [3] Additionally, evidence suggests that fires that occur outside of normal seasonal burn times (typically summer months) can have negative repercussions on pyrogenic flowering plants, including lower flowering and seed production when compared to fire-exposed plants during normal burn times. [8] [1] Competition between pyrogenic flowering plants may also be impacted by the anthropogenic control of fire, as alteration of fire seasons or fire intensity may favour one species over another. [1]

Pyrogenic flowering plants

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<span class="mw-page-title-main">Nymphaeaceae</span> Family of plants

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<i>Xanthorrhoea</i> Genus of flowering plants

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<span class="mw-page-title-main">Waratah</span> Genus of plants in the family Proteaceae from southeastern Australia

Waratah (Telopea) is an Australian-endemic genus of five species of large shrubs or small trees, native to the southeastern parts of Australia. The best-known species in this genus is Telopea speciosissima, which has bright red flowers and is the New South Wales (NSW) state emblem. The waratah is a member of the family Proteaceae, flowering plants distributed in the Southern Hemisphere. The key diagnostic feature of Proteaceae is the inflorescence, which is often very large, brightly coloured and showy, consisting of many small flowers densely packed into a compact head or spike. Species of waratah boast such inflorescences ranging from 6–15 cm in diameter with a basal ring of coloured bracts. The leaves are spirally arranged, 10–20 cm long and 2–3 cm broad with entire or serrated margins. The name waratah comes from the Eora Aboriginal people, the pre-European inhabitants of the Sydney area.

<i>Telopea speciosissima</i> Large shrub in the plant family Proteaceae endemic to New South Wales in Australia

Telopea speciosissima, commonly known as the New South Wales waratah or simply waratah, is a large shrub in the plant family Proteaceae. It is endemic to New South Wales in Australia and is the floral emblem of that state. No subspecies are recognised, but the closely related Telopea aspera was only recently classified as a separate species.

<span class="mw-page-title-main">Telopea, New South Wales</span> Suburb of Sydney, New South Wales, Australia

Telopea is a suburb of Greater Western Sydney, in the state of New South Wales, Australia. Telopea is located 23 kilometres north-west of the Sydney central business district, in the local government area of the City of Parramatta. The suburb is bordered by Kissing Point Road to the south and Pennant Hills Road to the north.

<i>Doryanthes excelsa</i> Species of flowering plant

Doryanthes excelsa, commonly known as the gymea lily, is a flowering plant in the family Doryanthaceae that is endemic to coastal areas of New South Wales near Sydney. It has sword-like leaves more than 1 metre (3 ft) long and it grows a flower spike up to 6 metres (20 ft) high. The apex of the spike bears a large cluster of bright red flowers, each 10 centimetres (4 in) across. Its common name is derived from the name given to the plant by the indigenous [Dharawal] people. The Sydney suburbs of Gymea and Gymea Bay are named after the lily.

<span class="mw-page-title-main">Serotiny</span> Seed release in response to environment

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<span class="mw-page-title-main">Proteaceae</span> Family of flowering plants

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<span class="mw-page-title-main">Parasitic plant</span> Type of plant that derives some or all of its nutritional requirements from another living plant

A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called the haustorium, which penetrates the host plant, connecting them to the host vasculature – either the xylem, phloem, or both. For example, plants like Striga or Rhinanthus connect only to the xylem, via xylem bridges (xylem-feeding). Alternately, plants like Cuscuta and some members of Orobanche connect to both the xylem and phloem of the host. This provides them with the ability to extract resources from the host. These resources can include water, nitrogen, carbon and/or sugars Parasitic plants are classified depending on the location where the parasitic plant latches onto the host, the amount of nutrients it requires, and their photosynthetic capability. Some parasitic plants can locate their host plants by detecting volatile chemicals in the air or soil given off by host shoots or roots, respectively. About 4,500 species of parasitic plants in approximately 20 families of flowering plants are known.

<i>Alloxylon flammeum</i> Species of tree in the family Proteaceae

Alloxylon flammeum, commonly known as the Queensland tree waratah or red silky oak, is a medium-sized tree of the family Proteaceae found in the Queensland tropical rain forests of northeastern Australia. It has shiny green elliptical leaves up to 18 cm (7.1 in) long, and prominent orange-red inflorescences that appear from August to October, followed by rectangular woody seed pods that ripen in February and March. Juvenile plants have large deeply lobed pinnate leaves. Previously known as Oreocallis wickhamii, the initial specimen turned out to be a different species to the one cultivated and hence a new scientific name was required. Described formally by Peter Weston and Mike Crisp in 1991, A. flammeum was designated the type species of the genus Alloxylon. This genus contains the four species previously classified in Oreocallis that are found in Australasia.

<i>Lambertia formosa</i> Shrub of the family Proteaceae, endemic to New South Wales, Australia

Lambertia formosa, commonly known as mountain devil, is a shrub of the family Proteaceae, endemic to New South Wales, Australia. First described in 1798 by English botanist James Edward Smith, it is the type species of the small genus Lambertia. It is generally found in heathland or open forest, growing in sandstone-based soils. It grows as a multistemmed shrub to around 2 m (7 ft) with a woody base known as a lignotuber, from which it regrows after bushfire. It has stiff narrow leaves, and the pink to red flowerheads, made up of seven individual tubular flowers, generally appear in spring and summer. It gains its common name from the horned woody follicles, which were used to make small devil-figures.

<i>Telopea mongaensis</i> Species of plant in the family Proteaceae endemic to south eastern New South Wales, Australia

Telopea mongaensis, commonly known as the Monga waratah or Braidwood waratah, is a shrub or small tree in the family Proteaceae. Endemic to Australia, it grows at high altitude in south eastern New South Wales, where it is often seen in moist areas at the edge of rainforest or by streams in eucalyptus forests. Growing to 6 m (20 ft) high, it has narrow green leaves 4–18 cm (1.6–7.1 in) in length, and 0.5–2 cm (0.20–0.79 in) wide. In spring bears many red flowerheads, each made up of 28 to 65 individual flowers.

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Telopea oreades, commonly known as the Gippsland-, mountain- or Victorian waratah, is a large shrub or small tree in the family Proteaceae. Native to southeastern Australia, it is found in wet sclerophyll forest and rainforest on rich acidic soils high in organic matter. No subspecies are recognised, though a northern isolated population hybridises extensively with the Braidwood waratah (T. mongaensis). Reaching a height of up to 19 metres, T. oreades grows with a single trunk and erect habit. It has dark green leaves with prominent veins that are 11–28 centimetres (4.3–11 in) long and 1.5–6 cm (0.6–2.4 in) wide. The red flower heads, known as inflorescences, appear in late spring. Each is composed of up to 60 individual flowers.

<i>Telopea truncata</i> Shrub in the family Proteaceae endemic to Tasmania

Telopea truncata, commonly known as the Tasmanian waratah, is a plant in the family Proteaceae. It is endemic to Tasmania where it is found on moist acidic soils at altitudes of 600 to 1200 m (2000–4000 ft). Telopea truncata is a component of alpine eucalypt forest, rainforest and scrub communities. It grows as a multistemmed shrub to a height of 3 metres (10 ft), or occasionally as a small tree to 10 m (35 ft) high, with red flower heads, known as inflorescences, appearing over the Tasmanian summer and bearing 10 to 35 individual flowers. Yellow-flowered forms are occasionally seen, but do not form a population distinct from the rest of the species.

<i>Telopea aspera</i> Species of plant in the family Proteaceae from New South Wales in Australia

Telopea aspera, commonly known as Gibraltar Range waratah, is a plant in the family Proteaceae. It grows as a woody shrub to 3 metres (10 ft) high with leathery rough leaves and bright red flower heads known as inflorescences—each composed of hundreds of individual flowers. It is endemic to the New England region in New South Wales in Australia. It was formally described as a species by botanists Peter Weston and Mike Crisp in 1995, separated from its close relative Telopea speciosissima by its rough foliage and preference for dryer habitat. Unlike its better known relative, Telopea aspera has rarely been cultivated.

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Alloxylon pinnatum, known as Dorrigo waratah, is a tree of the family Proteaceae found in warm-temperate rainforest of south-east Queensland and northern New South Wales in eastern Australia. It has shiny green leaves that are either pinnate (lobed) and up to 30 cm (12 in) long, or lanceolate (spear-shaped) and up to 15 cm (5.9 in) long. The prominent pinkish-red flower heads, known as inflorescences, appear in spring and summer; these are made up of 50 to 140 individual flowers arranged in corymb or raceme. These are followed by rectangular woody seed pods, which bear two rows of winged seeds.

<span class="mw-page-title-main">Resprouter</span>

Resprouters are plant species that are able to survive fire by the activation of dormant vegetative buds to produce regrowth.

Flowering synchrony is the amount of overlap between flowering periods of plants in their mating season compared to what would be expected to occur randomly under given environmental conditions. A population which is flowering synchronously has more plants flowering at the same time than would be expected to occur randomly. A population which is flowering asynchronously has fewer plants flowering at the same time than would be expected randomly. Flowering synchrony can describe synchrony of flowering periods within a year, across years, and across species in a community. There are fitness benefits and disadvantages to synchronized flowering, and it is a widespread phenomenon across pollination syndromes.

<span class="mw-page-title-main">Fire adaptations</span> Traits of plants and animals

Fire adaptations are traits of plants and animals that help them survive wildfire or to use resources created by wildfire. These traits can help plants and animals increase their survival rates during a fire and/or reproduce offspring after a fire. Both plants and animals have multiple strategies for surviving and reproducing after fire. Plants in wildfire-prone ecosystems often survive through adaptations to their local fire regime. Such adaptations include physical protection against heat, increased growth after a fire event, and flammable materials that encourage fire and may eliminate competition.

References

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