Friday Fellow: Titan Arum

by Piter Kehoma Boll

Today our fellow is another star of the plant kingdom and you probably heard of it before. Growing in the rainforests of Sumatra and Java, this species has a giant inflorescence and emits a smell of rotten meat, sometimes being called corpse flower, but do not mistake it for another rotten meat-smelling giant flower from the same place, the corpse flower Rafflesia arnoldi already presented here some years ago.

The giant inflorescence of the titan arum. Photo by Wikimedia user Rhododendrites.*

The name of today’s species if Amorphophallus titanum, which literally means something like “titan shapeless penis”. The name may not please many audiences, so the common name “titan arum” was coined by the British naturalist and broadcaster David Attenborough.

The titan arum belongs to the family Araceae, the same that includes some popular garden plants such as the anthurium. It is the flowering plant with the largest unbranched inflorescence in the world. The giant structure is not a single flower, but a giant inflorescence, called spadix, containing many small flowers and surrounded by a single petal-like leaf called spathe. In most species of Araceae the whole spadix contains flowers, but in the titan arum they are present only at two rings at the base, an upper ring of male flowers and a lower ling of female flowers. Most of the spadix is just a giant hollow appendix.

Male flowers (above) and female flowers (below) seen through a cut of the spathe. Photo by Wikimedia user Rosetta.**

The inflorescence of the titan arum can reach over 3 meters in height. It emits a fragrance that resembles that of rotting meat and attracts the pollinators, which are carrion-eating beetles and flesh flies. In fact, the odor changes during the opening and maturation of the inflorescence, but always resembles something decomposing. While the spathe is opening, the smell is more like that of rotten fruits, a few hours later it changes to a more rotten-egg smell and then to a real rotting-meat smell. During this last phase, the temperature of the inflorescence increases, reaching up to 36°C, about the temperature of a mammal, and this is considered as a probable additional feature to simulate the rotting meat appearance of the structure. Furthermore, the inner surface of the spathe has a deep-red to purple color that also resembles rotting meat.

The single giant leaf of the titan arum. Photo by Emőke Dénes.*

Like many giant-flowered or giant-inflorescenced species, the titan arum is not a very leafy species. While the inflorescence is growing and opening, the plants does not have any leaf. After the inflorescence dies and fruits are produced, a single giant leaf starts to grow from the plants subterranean corm (a stem working as a storage organ), reaching the size of a small tree. The corm, as everything in this species, is also giant, being the largest known corm in the world, usually reaching aroound 50 kg, but some specimens in botanical gardens going beyond 100 kg after some years.

The giant corm of the titan arum. Photo by Wikimedia user Georgialh.*

The titan arum is really one of the most remarkable species on our planet. Don’t you agree?

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References:

Korotkova, N.; Barthlott, W. (2009) On the thermogenesis of the Titan arum (Amorphophallus titanum). Plant Signaling & Behavior, 4(11): 1096–1098.

Shirasu, M.; Fujioka, K.; Kakishima, S.; Nagai, S.; Tomizawa, Y.; Tsukaya, H.; Murata, J.; Manome, Y.; Touhara, K. (2010) Chemical identity of a rotting animal-like odor emitted from the inflorescence of the titan arum (Amorphophallus titanum). Bioscience, Biotechnology and Biochemistry 74(12): 2550–2554.

Wikipedia. Amorphophallus titanum. Available at < https://en.wikipedia.org/wiki/Amorphophallus_titanum >. Access on June 14, 2018.

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This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

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Friday Fellow: Spreading Earthmoss

by Piter Kehoma Boll

If you still think mosses are uninteresting lifeforms, perhaps you will change your mind after knowing the spreading earthmoss, Physcomitrella patens.

Found in temperate regions of the world, except for South America, but more commonly recorded in North America and Eurasia, the spreading earthmoss grows near water bodies, being one of the first species to colonize the exposed soil around pools of water. Although widely distributed, it is not a common species.

The spreading earthmoss growing on mud. Photo by Hermann Schachner.

Since the beginning of the 1970s, the spreading earthmoss has been used as a model organism, especially regarding gene manipulation. Differently from what occurs in vascular plants, the dominant life phase in mosses is the gametophyte, an haploid organism, meaning it has only one copy of each chromosome in its cells. This is an ideal condition for the study of gene expression, as the activation or inactivation of a gene is not hindered by a second one in another copy of the chromosome in the same cell.

Physcomitrella patens growing in the lab. Credits to the Lab of Ralf Reski.*

By controlling gene expression in the spreading earthmoss, researches can track the role of each one of them in the plant’s development. Comparing these data with that known from flowering plants, we can have a better understanding of how the plant kingdom evolved.

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References:

Cove, D. (2005). The Moss Physcomitrella patens Annual Review of Genetics, 39 (1), 339-358 DOI: 10.1146/annurev.genet.39.073003.110214

Schaefer, D. (2001). The Moss Physcomitrella patens, Now and Then PLANT PHYSIOLOGY, 127 (4), 1430-1438 DOI: 10.1104/pp.127.4.1430

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Friday Fellow: Mexican Giant Horsetail

by Piter Kehoma Boll

If you are walking through the forest of Central America, you may end up finding something that at first you could think is a group of bamboos, plants growing as a cylindrical segmented stem that can reach up to 7 m in height, as seen in the picture below:

A group of bamboos? Not exactly. Photo by Alex LomasAlex Lomas.*

Those are not actually bamboos, though, but specimens of the largest species of horsetail that exists today, the Mexican giant horsetail, Equisetum myriochaetum. It can be found growing naturally from Peru to Mexico in areas of fertile soil, especially along water bodies such as streams and swamps.

As other horsetails, the Mexican giant horsetail has an erect and hollow stem with very narrow leaves growing in a whirl around the “joints” of the stem. The leaves are very simple, similar to those of more primitive plants such as the spikemosses and ground pines, but are thought to be a simplification of more complex leaves, as they are more closely related to the complex-leaved ferns.

More than only the largest horsetail in the world, the Mexican giant horsetail is an important medicinal plant in Mexican folk medicine, being used to treat kidney diseases and type 2 diabetes mellitus. And as in many other occasions, laboratory studies confirmed that water extracts from the aerial parts of E. myriochaetum do indeed reduce the blood glucose levels of type 2 diabetic patients without reducing their insulin levels. One more point to traditional medicine.

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References:

EOL – Encyclopedia of Life. Equisetum myriochaetum. Available at <http://eol.org/pages/6069616/overview&gt;. Access on March 4, 2017.

Revilla, M., Andrade-Cetto, A., Islas, S., & Wiedenfeld, H. (2002). Hypoglycemic effect of Equisetum myriochaetum aerial parts on type 2 diabetic patients Journal of Ethnopharmacology, 81 (1), 117-120 DOI: 10.1016/S0378-8741(02)00053-3

Royal Botanic Garden Edinburgh. Equisetum myriochaetum. Available at <http://www.rbge.org.uk/the-gardens/plant-of-the-month/plant-profiles/equisetum-myriochaetum&gt;. Access on March 4, 2017.

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Friday Fellow: Paraná pine

by Piter Kehoma Boll

As the first conifer Friday Fellow, I decided to choose one of my beloved ones, the Paraná pine, Araucaria angustifolia, also known as Brazilian pine or candelabra tree.

The Paraná pine can reach up to 50 m in height, although most trees are smaller than that. They have a very particular shape and are easily distinguished from the surrounding forest where they occur, the so-called Mixed Ombrophilous Forest or Araucaria Moist Forest, in southern Brazil. The trees have a cylindrical trunk with a dark and thin bark that detaches in large and flexible pieces, being gray on the outer surface and reddish on the inner one. The crown changes its appearance during the development, being conical in young trees and with a candelabrum-like shape in mature specimens. Mature trees usually stand with their crowns above the forest canopy, which gives the Araucaria moist forest its particular look. The leaves grow in a spiral pattern around the stem and are very hard with a sharp point that can easily pierce through the human skin.

A group of Paraná pines in Campos de Jordão, Brazil, close to the northernmost distribution of the species. Photo by Vinícius Ribeiro.*

The species current distribution is almost restricted to Brazil, from northern Rio Grande do Sul to southern São Paulo, with some small populations occurring in neighboring areas of Argentina and Paraguay. Once an abundant species, its population has been drastically reduced due to the heavy logging until the middle of the 20th century and the exploitation for the use of its seeds, called pinhão in Portuguese. As a result, it is currently considered as Critically Endangered by IUCN.

An adult tree in the municipality of Colombo, Paraná, Brazil. Photo by Mauro Guanandi.*

The paraná pine is a dioecious species, i.e., males and females are separate plants. As most conifers, it is pollinated by the wind. The large cones, which take two years to become ripe, contain a number of large and edible seeds used as food by many animals, as well as by humans. Pinhões cooked in salty water is a typical dish in southern Brazil during winter. One of the main seed dispersers of the Paraná pine is the azure jay, Cyanocorax caeruleus, which buries the seeds for future use.

A cone and lose seeds of Araucaria angustifolia in a market. Photo by Marcelo Träsel.**

As most (if not all) conifers, the Paraná pine forms mutualist associations with fungi, such as the glomeromycete Glomus clarum. Thus, in order to preserve this amazing tree, it is also necessary to guarantee the preservation of all its partner species, such as mycorrhizal fungi and seed dispersers.

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References:

Angeli, A. (2003). Araucaria angustifolia (Araucaria). Departamento de Ciências Florestais – ESALQ/USP. Available at: <http://www.ipef.br/identificacao/araucaria.angustifolia.asp&gt;. Access on January 26, 2017.

IUCN (2016). Araucaria angustifolia The IUCN Red List of Threatened Species DOI: 10.2305/IUCN.UK.2013-1.RLTS.T32975A2829141.en

Soares, T. S. (2004). Araucária – o pinheiro brasileiro. Revista Científica Eletrônica de Engenharia Florestal, 2 (3).

SOUZA, A. (2007). Ecological interpretation of multiple population size structures in trees: The case of Araucaria angustifolia in South America Austral Ecology, 32 (5), 524-533 DOI: 10.1111/j.1442-9993.2007.01724.x

Zandavalli, R., Dillenburg, L., & de Souza, P. (2004). Growth responses of Araucaria angustifolia (Araucariaceae) to inoculation with the mycorrhizal fungus Glomus clarum. Applied Soil Ecology, 25 (3), 245-255 DOI: 10.1016/j.apsoil.2003.09.009

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This work is licensed under a Creative Commons Attribution 2.0 Generic License.

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Friday Fellow: Peacock Spikemoss

by Piter Kehoma Boll

This is the last Friday Fellow of the year and I decided to choose a beautiful and little known plant, the peacock spikemoss, more commonly known as Willdenow’s spikemoss or peacock fern, and scientifically known as Selaginella willdenowii.

The most impressive feature of this species is the blue iridescence of its leaves, which can be quite intense depending on the light reflecting on them. This blue color is caused by a very thin layer of cells in the upper cuticle of the leaves that produces a thin-film interference, a phenomemon such as the one that makes a soap bubble look colorful.

Look how blue it can get! Amazing, huh? Photo by Bernard Dupont.*

The peacock spikemoss is native from Southeast Asia, more precisely from the region around Singapore, and is adapted to areas of extreme shade. The blue iridescence is therefore an adaptation to reflect the strong sunlight that may reach the plant through openings in the canopy.

Some Asian cultures use the peacock spikemoss in traditional medicine and studies have shown that the plant has important antioxidant properties. So why not to try an iridescent blue tea?

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References:

Chai, Tsun-Thai, & Wong, Fai-Chu (2012). Antioxidant properties of aqueous extracts of Selaginella willdenowii Journal of Medicinal Plants Research, 6 (7) DOI: 10.5897/JMPR11.1378

EOL – Encyclopedia of Life. Willdenow’s Spikemoss. Available at: <http://eol.org/pages/595324/overview&gt;. Access on December 28, 2016.

Wikipedia. Selaginella willdenowii. Available at: <https://en.wikipedia.org/wiki/Selaginella_willdenowii&gt;. Access on December 28. 2016.

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