Platypodium elegans
Encyclopedia
Platypodium elegans or the graceful platypodium is a large leguminous tree found in the Neotropics that forms part of the forest canopy. It was first described by Julius Rudolph Theodor Vogel
in 1837 and is the type species
of the genus. The tree has been known to grow up to 30 metres in height and have a trunk with a diameter up to 1 m at breast height
. Its trunk has large holes in it, sometimes making it possible to see through the trunk. The holes provide a habitat for giant damselflies and other insects both when alive and once the tree has died and fallen over. It has compound leaves each of which is made up of 10–20 leaflets. Three new chemical compounds have been isolated from the leaves and they form part of the diet of several monkeys and the squirrel Sciurus ingrami
. In Panama it flowers from April to June, the flowers contain only four ovules, but normally only one of these reaches maturity forming a winged seed pod
around 10 cm long and weighing 2 g. During the dry season around a year after the flowers are fertilised, the seeds are dispersed by the wind and the tree loses it leaves. The seeds are eaten by agoutis and by bruchid beetle larvae. The majority of seedlings are killed by damping off
fungi in the first few months of growth, with seedlings that grow nearer the parent trees being more likely to die. The seedlings are relatively unable to survive in deep shade
compared to other species in the same habitat. Various epiphyte
s are known to grow on P. elegans with the cactus Epiphyllum phyllanthus
being the most abundant in Panama. Despite having holes in its trunk which should encourage debris and seeds to collect, hemiepiphyte
s are relatively uncommon, possibly due to the seeds being dispersed by wind, meaning that animals are not attracted to it to feed and then defecate. It has no known uses in traditional medicine
and although it can be used for timber, the wood is of poor quality.
(dbh) of 75–100 cm. Trees over 20 cm dbh grow at a rate of around 0.5 cm per year, as measured by how their dbh increases. Its trunk is fenestrated
, having large and conspicuous holes in it, even so much so that it is possible to see through the trunk, meaning it can be mistaken for a strangler fig
. The bark is soft and dark brown and contains a foul-smelling sap. It has compound leaves which grow up to 25 cm in length, each having 10–20 leaflets, which are 2.5–7.5 cm long, 1–3 cm wide, hairless on the upper side and positioned not quite opposite each other. Three new compounds have been isolated from the leaves of P. elegans; two seco-lupane triterpene
s (canaric acid and dihydrocanaric acid), as well as a coumarin
, 6,7,8-trimethoxycoumarin. The mature leaves are relatively tough, requiring more than 100 g/mm2 to be applied to them to puncture them. It is deciduous, losing its leaves during the dry season, when its seeds are dispersed. The diameter of the conducting vessels
in the roots are on average 69 μm
, up to 98 μm and in the shoots 57 μm up to 87 μm. The trees (over 20 cm dbh) are relatively stiff
compared to other trees on Barro Colorado Island
(BCI), having a Young's modulus
of 180,000 kg/cm2.
In Panama, it flowers from April to June. It was first reported to flower only every other year, but this is now known to be incorrect, although seed production can vary considerably from year to year. The flowers of P. elegans contain four ovules, but normally only the most distal ovule develops in to a seed, with other seeds being aborted before they mature. The pedicel
s are 8–12 mm long, the bract
s around 2 mm long and the calyx around 4 mm long. After being fertilised a winged fruit (a samara
) develops quickly, but it takes around one year for the seed to mature. The fruit remains on the tree whilst the seeds develop and is thought to photosynthesise during this time. The samaras dry out during the dry season, before detaching from the tree and being dispersed by the wind over 2–3 months. In Panama the seeds are dispersed between February and April, just under a year after the flowers formed. Each samara normally only contains one seed, but sometimes they contain two instead, which affects their dispersal. The samaras vary in size and shape between trees, but are generally similar on each individual tree. On average, they weigh around 2 g when dry, and are around 10 cm long but can grow up to 16 cm. Samaras containing two seeds are heavier, have a larger surface area and fall faster from the tree than those containing only one seed. Each seed weighs around one third of a gram, making them relatively large compared to other trees in its habitat, but seeds that are the result of self-fertilisation are significantly lighter (by 0.03 g). The cotyledon
s, of the seedlings remain underground after germination and only serve as a stored source of nutrients, they detach within 8 weeks of germination.
in 1837 and it is the type species
of the Platypodium
genus. In 1862 George Bentham
described a variety, Platypodium elegans var. major. In 1917 Henri François Pittier
described Platypodium maxonianum from Chiriqui
, Panama, noting that it differed from Vogel's description of P. elegans as it had larger leaves and fruits. He named the species after William Maxon, then a curator of the United States National Herbarium. P. maxonianum is now considered to be a synonym
of P. elegans. According to The Plant List
, P. elegans is currently one of only two accepted species of Platypodium, the other being P. viride
.
There are many common names for P. elegans in different languages. In English it is known as the graceful platypodium and similarly, in French as platypodium graceiux. In Brazil it has several names: amendoim-do-campo, amendoim-bravo, jacarandá-branco, jacarandá-bana, jacarandá-do-campo, jacarandazinho, jacarandá-tã, faviero, secupiruna and uruvalheira. Several names are also used in Panama: carcuera, costilla, arbol soga, canalua, canaleto and tigre. In Paraguay it is known as desconocido and in Colombia as lomo de caimán.
s and savannah
of the Neotropics, ranging from Panama
in the North, to Paraguay
in the South. It is also found in Bolivia, Brasil, Colombia and Venezuela. It is not found in the central and northern parts of Brazil, but is found in the cerrado
, Mato Grosso
, Minas Gerais
and around Sao Paulo
. On Barro Colorado Island (BCI) P. elegans is found at a moderate abundance in both old and young forest, each hectare may contain several mature trees, but it is not unusual to find isolated individuals. Generally, only large individuals are found, with saplings being rare, except in forest gaps.
) is estimated to be between 25 and 50 hectares around each tree. 92% of seeds that mature result from flowers that have been pollinated with pollen from other individuals
but self-fertilisation is actually much higher than this would suggest. The difference between these values is explained by the fact that many fruits are aborted after being fertilised, but before dispersal occurs. Hufford and Hamrick suggested that they abort fruit for two reasons; they could have a set amount of resources to invest in their seeds in one year but produce extra flowers which then compete between each other, with only some surviving to maturity. Alternatively, the tree may detect which fruits are the result of self-fertilisation and selectively abort them, but this is considered less likely. The seeds are dispersed
by wind.
In Panama the seeds germinate at the start of the rainy season in May. Damping off
fungi account for 64–95% of the deaths of seedlings during their first three months of growth, with deaths being more common for seedlings near their parents, as the Janzen-Connell hypothesis
predicts. Falling leaf litter and digging mammals are also significant causes of seedling mortality. An artificial experiment found that if seedlings have their leaves removed or are placed in deep shade (0.08% of full sunlight) they die within 60 days, whereas around 80% of the seedlings of Lacmellea panamensis
are able to survive these treatments. The seedlings are able to grow slowly in 0.8% sunlight, but the seedlings are at the low end of the spectrum in terms of being able to tolerate shade
. Another experiment has shown that seedlings die faster if either their cotyledons or leaves are removed, those that have had their cotyledons removed die more quickly.
bacteria, in this case from the Bradyrhizobium
genus. Genetic analysis of the bacteria has shown that different genotype
s colonise the roots of the same tree and are strains of Bradyrhizobium japonicum
.
The epiphytic
cactus, Epiphyllum phyllanthus
is particularly abundant in the canopies of P. elegans on BCI particularly growing in cavities in the trunk. Another cactus Rhipsalis baccifera
and the ferns Niphidium crassifolium
and Campyloneurum phyllitidis
are also found growing on P. elegans. After rainfall the bark stores around one third of a gram of water per cm2 which epiphytes can the absorb, a moderate amount compared to other trees. Todzia found that despite having a trunk with deep invaginations that collect debris and which should encourage the germination of seeds, hemiepiphyte
s (plants which germinate on the tree and then send down roots into the soil) are relatively rare on P. elegans on BCI. It is though that this is because its seeds are wind dispersed, and the tree therefore attracts relatively few animals which could deposit the seeds of hemiepiphytes whilst feeding on seeds. Todzia noted that Hura crepitans disperses it seeds explosively
, yet is heavily laden with hemiepiphytes however. A survey of 20 trees on BCI with a diameter at breast height
of 20 cm or more, found that 75 % had liana
s growing on them.
Various invertebrates live in water filled holes
which form in ridges of the trunk of P. elegans when they die and fall over, and in tree hollow
s that exist when the tree is alive. Leaf litter collects in the water and as it decomposes animals feed on the debris. An experiment, where leaves of P. elegans were added to an artificial pool containing 650 ml of water in the rainforest found that 17 species lived in them, with the mosquito Culex mollis being the most abundant. The pools contained a greater species diversity and abundance of animals than similar experiments using leaves of Ceiba pentandra, Dipteryx panamensis and Ficus yoponensis
; species that also contain water pools in their trunks. Yanoviak suggested that this indicates that the leaves are a relatively higher-quality nutrient source, than those of the other species. On BCI, Fincke found that trees had between 1 and 10 water filled holes, more than any other tree species investigated, each containing on average 2 litres of water. Yanoviak found that the holes contained only 400 ml of water on average however. The pools are an important habitat for the larvae of giant damselflies
. As a coloniser of new habitats, P. elegans may provide an ideal habitat for giant damselflies in secondary forest
. The beetle Microvelia cavicola also lives in the water filled holes, with the type specimen of the species being found in one.
The embryos of immature fruit are eaten by agoutis (Dasyprocta punctata) once they have fallen to the forest floor. Mature seeds can be infected by fungi and are also eaten by bruchid beetle larvae. The squirrel, Sciurus ingrami
eats the leaves of P. elegans on BCI, but not in Southeastern Brazil. Woolly spider monkeys
in Brazil feed extensively on the leaves in October, prior to the beginning of their mating season. The leaves are thought to be low in tannin
s and other secondary metabolite
s which hinder protein digestion, making them an ideal food before the mating season. They also contain phytoestrogens which can change the monkey's estrogen
levels, possibly affecting their fertility. Both young and mature leaves of P. elegans are eaten by howler monkeys, as the leaves mature, the protein content decreases, the cell wall content increases, but the proportion of non-structural carbohydrates remains equal. When fresh, the leaves contain between 100 and 200 mg of ascorbic acid
(Vitamin C
) per 100 g, like humans some primates on BCI require in their diet, since they do not possess the gene for L-gulonolactone oxidase
, the enzyme required to convert glucose to ascorbic acid.
Julius Rudolph Theodor Vogel
Julius Rudolph Theodor Vogel was a botanist. His author abbreviation is Vogel.-References:...
in 1837 and is the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the genus. The tree has been known to grow up to 30 metres in height and have a trunk with a diameter up to 1 m at breast height
Diameter at breast height
Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements....
. Its trunk has large holes in it, sometimes making it possible to see through the trunk. The holes provide a habitat for giant damselflies and other insects both when alive and once the tree has died and fallen over. It has compound leaves each of which is made up of 10–20 leaflets. Three new chemical compounds have been isolated from the leaves and they form part of the diet of several monkeys and the squirrel Sciurus ingrami
Sciurus ingrami
Sciurus ingrami, commonly known as Ingram's squirrel and serelepe, is a squirrel found in South America regarded variously as a species or as a subspecies of the Brazilian squirrel. It is solitary and territorial, but has been seen to act together and mob a predatory cat, the margay....
. In Panama it flowers from April to June, the flowers contain only four ovules, but normally only one of these reaches maturity forming a winged seed pod
Samara (fruit)
A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...
around 10 cm long and weighing 2 g. During the dry season around a year after the flowers are fertilised, the seeds are dispersed by the wind and the tree loses it leaves. The seeds are eaten by agoutis and by bruchid beetle larvae. The majority of seedlings are killed by damping off
Damping off
Damping off is the term used for a number of different fungus-caused ailments that can kill seeds or seedlings before or after they germinate....
fungi in the first few months of growth, with seedlings that grow nearer the parent trees being more likely to die. The seedlings are relatively unable to survive in deep shade
Shade tolerance
In ecology, shade tolerance is a plant's abilities to tolerate low light levels. The term is also used in horticulture and landscaping, although in this context its use is sometimes sloppy, especially with respect to labeling of plants for sale in nurseries....
compared to other species in the same habitat. Various epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
s are known to grow on P. elegans with the cactus Epiphyllum phyllanthus
Epiphyllum phyllanthus
Epiphyllum phyllanthus, commonly known as the climbing cactus is a species of epiphytic cacti. It has no leaves, instead having stems that photosynthesise...
being the most abundant in Panama. Despite having holes in its trunk which should encourage debris and seeds to collect, hemiepiphyte
Hemiepiphyte
A hemiepiphyte is a plant which begins its life as an epiphyte but which later grows roots down into the ground. The seeds of hemiepiphytes germinate in the canopy and initially live epiphytically...
s are relatively uncommon, possibly due to the seeds being dispersed by wind, meaning that animals are not attracted to it to feed and then defecate. It has no known uses in traditional medicine
Traditional medicine
Traditional medicine comprises unscientific knowledge systems that developed over generations within various societies before the era of modern medicine...
and although it can be used for timber, the wood is of poor quality.
Description
Platypodium elegans is a large forest tree, which forms part of the forest canopy. It can grow up to 30 m in height, with mature trees having an average crown diameter of 16 m and a diameter at breast heightDiameter at breast height
Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements....
(dbh) of 75–100 cm. Trees over 20 cm dbh grow at a rate of around 0.5 cm per year, as measured by how their dbh increases. Its trunk is fenestrated
Fenestration (plant)
Fenestration is a term in botany that refers to natural holes in the leaves of some species of plants. The size, shape, and quantity of holes in each leaf can vary greatly depending on the species and can even vary greatly within a given species. Fenestration is caused by sections of leaf ceasing...
, having large and conspicuous holes in it, even so much so that it is possible to see through the trunk, meaning it can be mistaken for a strangler fig
Strangler Fig
Strangler fig is the common name for a number of tropical and subtropical plant species, including some banyans and unrelated vines, including among many other species:* Ficus aurea, also known as the Florida Strangler Fig...
. The bark is soft and dark brown and contains a foul-smelling sap. It has compound leaves which grow up to 25 cm in length, each having 10–20 leaflets, which are 2.5–7.5 cm long, 1–3 cm wide, hairless on the upper side and positioned not quite opposite each other. Three new compounds have been isolated from the leaves of P. elegans; two seco-lupane triterpene
Triterpene
Triterpenes are terpenes consisting of six isoprene units and have the molecular formula C30H48.The pentacyclic triterpenes can be classified into lupane, oleanane or ursane groups.Animal- and plant-derived triterpenes exist, such as:*squalene...
s (canaric acid and dihydrocanaric acid), as well as a coumarin
Coumarin
Coumarin is a fragrant chemical compound in the benzopyrone chemical class, found in many plants, notably in high concentration in the tonka bean , vanilla grass , sweet woodruff , mullein , sweet grass , cassia cinnamon and sweet clover...
, 6,7,8-trimethoxycoumarin. The mature leaves are relatively tough, requiring more than 100 g/mm2 to be applied to them to puncture them. It is deciduous, losing its leaves during the dry season, when its seeds are dispersed. The diameter of the conducting vessels
Vascular tissue
Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue:...
in the roots are on average 69 μm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
, up to 98 μm and in the shoots 57 μm up to 87 μm. The trees (over 20 cm dbh) are relatively stiff
Elasticity
Elasticity may refer to:*Elasticity , continuum mechanics of bodies that deform reversibly under stressNumerous uses are derived from this physical sense of the term, which is inherently mathematical, such as used in Engineering, Chemistry, Construction and variously in Economics:*Elasticity , the...
compared to other trees on Barro Colorado Island
Barro Colorado Island
Barro Colorado Island is located in the man-made Gatun Lake in the middle of the Panama Canal. The island was formed when the waters of the Chagres River were dammed to form the lake. When the waters rose, they covered a significant part of the existing rainforest, and the hilltops remained as...
(BCI), having a Young's modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...
of 180,000 kg/cm2.
In Panama, it flowers from April to June. It was first reported to flower only every other year, but this is now known to be incorrect, although seed production can vary considerably from year to year. The flowers of P. elegans contain four ovules, but normally only the most distal ovule develops in to a seed, with other seeds being aborted before they mature. The pedicel
Pedicel (botany)
A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....
s are 8–12 mm long, the bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s around 2 mm long and the calyx around 4 mm long. After being fertilised a winged fruit (a samara
Samara (fruit)
A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...
) develops quickly, but it takes around one year for the seed to mature. The fruit remains on the tree whilst the seeds develop and is thought to photosynthesise during this time. The samaras dry out during the dry season, before detaching from the tree and being dispersed by the wind over 2–3 months. In Panama the seeds are dispersed between February and April, just under a year after the flowers formed. Each samara normally only contains one seed, but sometimes they contain two instead, which affects their dispersal. The samaras vary in size and shape between trees, but are generally similar on each individual tree. On average, they weigh around 2 g when dry, and are around 10 cm long but can grow up to 16 cm. Samaras containing two seeds are heavier, have a larger surface area and fall faster from the tree than those containing only one seed. Each seed weighs around one third of a gram, making them relatively large compared to other trees in its habitat, but seeds that are the result of self-fertilisation are significantly lighter (by 0.03 g). The cotyledon
Cotyledon
A cotyledon , is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants...
s, of the seedlings remain underground after germination and only serve as a stored source of nutrients, they detach within 8 weeks of germination.
Taxonomy
Platypodium elegans was first described by Julius Rudolph Theodor VogelJulius Rudolph Theodor Vogel
Julius Rudolph Theodor Vogel was a botanist. His author abbreviation is Vogel.-References:...
in 1837 and it is the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the Platypodium
Platypodium
Platypodium is a genus of flowering plants in the legume family, Fabaceae. It belongs to the subfamily Faboideae....
genus. In 1862 George Bentham
George Bentham
George Bentham CMG FRS was an English botanist, characterized by Duane Isely as "the premier systematic botanist of the nineteenth century".- Formative years :...
described a variety, Platypodium elegans var. major. In 1917 Henri François Pittier
Henri François Pittier
Henri François Pittier was a Swiss-born geographer and botanist, who moved to Costa Rica in 1887, where he founded the Physical Geographic Institute and an herbarium. Henri Pittier National Park in Venezuela is named after him.-References:...
described Platypodium maxonianum from Chiriqui
Chiriquí
Chiriquí refers to one of the following, in or around Panama:* Chiriquí Province* Chiriquí River* Gulf of Chiriquí...
, Panama, noting that it differed from Vogel's description of P. elegans as it had larger leaves and fruits. He named the species after William Maxon, then a curator of the United States National Herbarium. P. maxonianum is now considered to be a synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
of P. elegans. According to The Plant List
The Plant List
The Plant List is a list of botanical names of species of plants, available on the world wide web. It was created by the Royal Botanic Gardens, Kew and the Missouri Botanical Garden...
, P. elegans is currently one of only two accepted species of Platypodium, the other being P. viride
Platypodium viride
Platypodium viride is a species of tree in the Fabaceae found in Peru. It is one of two accepted species of Platypodium, the other being P. elegans. It was first described by Julius Rudolph Theodor Vogel in 1837....
.
There are many common names for P. elegans in different languages. In English it is known as the graceful platypodium and similarly, in French as platypodium graceiux. In Brazil it has several names: amendoim-do-campo, amendoim-bravo, jacarandá-branco, jacarandá-bana, jacarandá-do-campo, jacarandazinho, jacarandá-tã, faviero, secupiruna and uruvalheira. Several names are also used in Panama: carcuera, costilla, arbol soga, canalua, canaleto and tigre. In Paraguay it is known as desconocido and in Colombia as lomo de caimán.
Distribution
Platypodium elegans is found in the rainforestRainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s and savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
of the Neotropics, ranging from Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
in the North, to Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
in the South. It is also found in Bolivia, Brasil, Colombia and Venezuela. It is not found in the central and northern parts of Brazil, but is found in the cerrado
Cerrado
The Cerrado, is a vast tropical savanna ecoregion of Brazil, particularly in the states of Gioas and Minas Gerais...
, Mato Grosso
Mato Grosso
Mato Grosso is one of the states of Brazil, the third largest in area, located in the western part of the country.Neighboring states are Rondônia, Amazonas, Pará, Tocantins, Goiás and Mato Grosso do Sul. It also borders Bolivia to the southwest...
, Minas Gerais
Minas Gerais
Minas Gerais is one of the 26 states of Brazil, of which it is the second most populous, the third richest, and the fourth largest in area. Minas Gerais is the Brazilian state with the largest number of Presidents of Brazil, the current one, Dilma Rousseff, being one of them. The capital is the...
and around Sao Paulo
São Paulo
São Paulo is the largest city in Brazil, the largest city in the southern hemisphere and South America, and the world's seventh largest city by population. The metropolis is anchor to the São Paulo metropolitan area, ranked as the second-most populous metropolitan area in the Americas and among...
. On Barro Colorado Island (BCI) P. elegans is found at a moderate abundance in both old and young forest, each hectare may contain several mature trees, but it is not unusual to find isolated individuals. Generally, only large individuals are found, with saplings being rare, except in forest gaps.
Ecology
Reproduction
Platypodium elegans is pollinated by bees. In Panama pollen is moved on average between 368 and 419 m from the parent tree and commonly over 1 km away. The population that regularly share genes (termed the demeDeme (biology)
In biology, a deme is a term for a local population of organisms of one species that actively interbreed with one another and share a distinct gene pool...
) is estimated to be between 25 and 50 hectares around each tree. 92% of seeds that mature result from flowers that have been pollinated with pollen from other individuals
Outcrossing
Outcrossing is the practice of introducing unrelated genetic material into a breeding line. It increases genetic diversity, thus reducing the probability of all individuals being subject to disease or reducing genetic abnormalities...
but self-fertilisation is actually much higher than this would suggest. The difference between these values is explained by the fact that many fruits are aborted after being fertilised, but before dispersal occurs. Hufford and Hamrick suggested that they abort fruit for two reasons; they could have a set amount of resources to invest in their seeds in one year but produce extra flowers which then compete between each other, with only some surviving to maturity. Alternatively, the tree may detect which fruits are the result of self-fertilisation and selectively abort them, but this is considered less likely. The seeds are dispersed
Seed dispersal
Seed dispersal is the movement or transport of seeds away from the parent plant. Plants have limited mobility and consequently rely upon a variety of dispersal vectors to transport their propagules, including both abiotic and biotic vectors. Seeds can be dispersed away from the parent plant...
by wind.
In Panama the seeds germinate at the start of the rainy season in May. Damping off
Damping off
Damping off is the term used for a number of different fungus-caused ailments that can kill seeds or seedlings before or after they germinate....
fungi account for 64–95% of the deaths of seedlings during their first three months of growth, with deaths being more common for seedlings near their parents, as the Janzen-Connell hypothesis
Janzen-Connell hypothesis
The Janzen-Connell hypothesis is a widely accepted explanation for the maintenance of tree species biodiversity in tropical rainforests. It was published independently in the early 1970s by Daniel Janzen and Joseph Connell...
predicts. Falling leaf litter and digging mammals are also significant causes of seedling mortality. An artificial experiment found that if seedlings have their leaves removed or are placed in deep shade (0.08% of full sunlight) they die within 60 days, whereas around 80% of the seedlings of Lacmellea panamensis
Lacmellea panamensis
Lacmellea panamensis is a species of tree in the Apocynaceae family. It is a medium-sized tree, with a straight trunk, that is scattered with conical spines that are rather blunt, a distinctive feature of the species. Its leaves are around long, spaced evenly along branches, simple in shape, dark...
are able to survive these treatments. The seedlings are able to grow slowly in 0.8% sunlight, but the seedlings are at the low end of the spectrum in terms of being able to tolerate shade
Shade tolerance
In ecology, shade tolerance is a plant's abilities to tolerate low light levels. The term is also used in horticulture and landscaping, although in this context its use is sometimes sloppy, especially with respect to labeling of plants for sale in nurseries....
. Another experiment has shown that seedlings die faster if either their cotyledons or leaves are removed, those that have had their cotyledons removed die more quickly.
Habitat
As in all legumes, the roots of P. elegans are colonised by nitrogen fixingNitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
bacteria, in this case from the Bradyrhizobium
Bradyrhizobium
Bradyrhizobium is a genus of Gram-negative soil bacteria, many of which fix nitrogen. Nitrogen fixation is an important part of the nitrogen cycle. Plants cannot use atmospheric nitrogen they must use nitrogen compounds such as nitrates....
genus. Genetic analysis of the bacteria has shown that different genotype
Genotype
The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...
s colonise the roots of the same tree and are strains of Bradyrhizobium japonicum
Bradyrhizobium japonicum
Bradyrhizobium japonicum is a species of legume-root nodulating, microsymbiotic nitrogen-fixing bacterium species. B. japonicum is identified as a DNA homology group .B...
.
The epiphytic
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
cactus, Epiphyllum phyllanthus
Epiphyllum phyllanthus
Epiphyllum phyllanthus, commonly known as the climbing cactus is a species of epiphytic cacti. It has no leaves, instead having stems that photosynthesise...
is particularly abundant in the canopies of P. elegans on BCI particularly growing in cavities in the trunk. Another cactus Rhipsalis baccifera
Rhipsalis baccifera
Rhipsalis baccifera, commonly known as the Mistletoe Cactus, is an epiphytic cactus which originates from Central and South America, the Caribbean and Florida. It is also spread throughout the tropics of Africa and Asia. This is the only cactus species naturally occurring outside the New World,...
and the ferns Niphidium crassifolium
Niphidium crassifolium
Niphidium crassifolium commonly known as the graceful fern is a species of fern in the Polypodiaceae family found in Central and South America. It is predominantly an epiphytic, growing on other plants for example in the canopies of trees, but is occasionally grows on rocks or on the ground,...
and Campyloneurum phyllitidis
Campyloneurum phyllitidis
Campyloneurum phyllitidis, commonly known as the long strap fern, is a species of fern in the Polypodiaceae family. It is an epiphyte, growing on other plants; generally the fern is found growing in the canopies of trees. It has a relatively large rhizome from which many fine rootlets covered in...
are also found growing on P. elegans. After rainfall the bark stores around one third of a gram of water per cm2 which epiphytes can the absorb, a moderate amount compared to other trees. Todzia found that despite having a trunk with deep invaginations that collect debris and which should encourage the germination of seeds, hemiepiphyte
Hemiepiphyte
A hemiepiphyte is a plant which begins its life as an epiphyte but which later grows roots down into the ground. The seeds of hemiepiphytes germinate in the canopy and initially live epiphytically...
s (plants which germinate on the tree and then send down roots into the soil) are relatively rare on P. elegans on BCI. It is though that this is because its seeds are wind dispersed, and the tree therefore attracts relatively few animals which could deposit the seeds of hemiepiphytes whilst feeding on seeds. Todzia noted that Hura crepitans disperses it seeds explosively
Dehiscence (botany)
Dehiscence is the opening, at maturity, in a pre-defined way, of a plant structure, such as a fruit, anther, or sporangium, to release its contents. Sometimes this involves the complete detachment of a part. Structures that open in this way are said to be dehiscent...
, yet is heavily laden with hemiepiphytes however. A survey of 20 trees on BCI with a diameter at breast height
Diameter at breast height
Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements....
of 20 cm or more, found that 75 % had liana
Liana
A liana is any of various long-stemmed, woody vines that are rooted in the soil at ground level and use trees, as well as other means of vertical support, to climb up to the canopy to get access to well-lit areas of the forest. Lianas are especially characteristic of tropical moist deciduous...
s growing on them.
Various invertebrates live in water filled holes
Phytotelmata
Phytotelma is a term for water bodies held by plants. The water accumulated on these plants may serve as substratum for associated fauna, and often the fauna associated with phytotelmata is unique....
which form in ridges of the trunk of P. elegans when they die and fall over, and in tree hollow
Tree hollow
A tree hollow or tree hole is a semi-enclosed cavity which has naturally formed in the trunk or branch of a tree. These are predominantly found in old trees, whether living or not...
s that exist when the tree is alive. Leaf litter collects in the water and as it decomposes animals feed on the debris. An experiment, where leaves of P. elegans were added to an artificial pool containing 650 ml of water in the rainforest found that 17 species lived in them, with the mosquito Culex mollis being the most abundant. The pools contained a greater species diversity and abundance of animals than similar experiments using leaves of Ceiba pentandra, Dipteryx panamensis and Ficus yoponensis
Ficus yoponensis
Ficus yoponensis is a species of fig tree found in Central and South America. It can grow to heights of tall, having a trunk diameter of . The trunk is buttressed, light grey in colour and reasonably smooth. Its petioles are long, the stipules are straight and long. The leaves and stems are...
; species that also contain water pools in their trunks. Yanoviak suggested that this indicates that the leaves are a relatively higher-quality nutrient source, than those of the other species. On BCI, Fincke found that trees had between 1 and 10 water filled holes, more than any other tree species investigated, each containing on average 2 litres of water. Yanoviak found that the holes contained only 400 ml of water on average however. The pools are an important habitat for the larvae of giant damselflies
Pseudostigmatidae
Pseudostigmatidae is a family of tropical damselflies, known as helicopter damselflies, giant damselflies or Forest Giants. The family includes the largest of all damselfly species...
. As a coloniser of new habitats, P. elegans may provide an ideal habitat for giant damselflies in secondary forest
Secondary forest
A secondary forest is a forest or woodland area which has re-grown after a major disturbance such as fire, insect infestation, timber harvest or windthrow, until a long enough period has passed so that the effects of the disturbance are no longer evident...
. The beetle Microvelia cavicola also lives in the water filled holes, with the type specimen of the species being found in one.
Food
Sciurus ingrami
Sciurus ingrami, commonly known as Ingram's squirrel and serelepe, is a squirrel found in South America regarded variously as a species or as a subspecies of the Brazilian squirrel. It is solitary and territorial, but has been seen to act together and mob a predatory cat, the margay....
eats the leaves of P. elegans on BCI, but not in Southeastern Brazil. Woolly spider monkeys
Muriqui
The muriquis, also known as woolly spider monkeys, are the monkeys of the genus Brachyteles. They are closely related to both the spider monkeys and the woolly monkeys. There are two species, the southern and northern muriqui...
in Brazil feed extensively on the leaves in October, prior to the beginning of their mating season. The leaves are thought to be low in tannin
Tannin
A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...
s and other secondary metabolite
Secondary metabolite
Secondary metabolites are organic compounds that are not directly involved in the normal growth, development, or reproduction of an organism. Unlike primary metabolites, absence of secondary metabolities does not result in immediate death, but rather in long-term impairment of the organism's...
s which hinder protein digestion, making them an ideal food before the mating season. They also contain phytoestrogens which can change the monkey's estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
levels, possibly affecting their fertility. Both young and mature leaves of P. elegans are eaten by howler monkeys, as the leaves mature, the protein content decreases, the cell wall content increases, but the proportion of non-structural carbohydrates remains equal. When fresh, the leaves contain between 100 and 200 mg of ascorbic acid
Ascorbic acid
Ascorbic acid is a naturally occurring organic compound with antioxidant properties. It is a white solid, but impure samples can appear yellowish. It dissolves well in water to give mildly acidic solutions. Ascorbic acid is one form of vitamin C. The name is derived from a- and scorbutus , the...
(Vitamin C
Vitamin C
Vitamin C or L-ascorbic acid or L-ascorbate is an essential nutrient for humans and certain other animal species. In living organisms ascorbate acts as an antioxidant by protecting the body against oxidative stress...
) per 100 g, like humans some primates on BCI require in their diet, since they do not possess the gene for L-gulonolactone oxidase
L-gulonolactone oxidase
L-gulonolactone oxidase is an enzyme that catalyzes the reaction of D-glucuronolactone with oxygen to L-xylo-hex-3-gulonolactone and hydrogen peroxide. It uses FAD as a cofactor...
, the enzyme required to convert glucose to ascorbic acid.
Uses
Platypodium elegans is not known to have any uses in traditional medicine. The Smithsonian Tropical Research Institute herbarium report its wood is used for timber, being described as "white, knotty, light and fragile". Pittier remarked in 1931 that the wood is little used in Panama however since the mature trunks are normally hollow and filled with an oily liquid.External links
- Photographs of Platypodium elegans from the Smithsonian Tropical Research InstituteSmithsonian Tropical Research InstituteThe Smithsonian Tropical Research Institute in Panama, the only bureau of the Smithsonian Institution based outside of the United States, is dedicated to understanding biological diversity. What began in 1923 as small field station on Barro Colorado Island in the Panama Canal Zone has developed...
Herbarium - Herbarium specimens from JSTOR plants.