Category Archives: Botany

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.

Physcomitrella_patens

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_ecotypes

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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ResearchBlogging.orgReferences:

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: Hooker’s Lips

by Piter Kehoma Boll

We are always fascinated by plants that have some peculiar shape that resemble something else. And certainly one of them is the species I’m introducing today, Psychotria elata, also known as hooker’s lips or hot lips.

Found in the rainforests of Central America, in areas of middle to high elevation, the hooker’s lips is an understory shrub and produces an inflorescence that is surrounded by a pair of bracts that resemble bright red lips. Don’t look too much or you may be tempted to kiss them.

psychotria_elata

“Kiss me”, beg the hooker’s lips. Photo by Wikimedia user IROZ.*

Certainly some creatures do kiss it, especially hummingbirds, which are its pollinators, but also many species of butterflies and bees. However, when they come to kiss the red lips, they have already spread to much, in order to allow the flowers to be exposed, and do not resemble a mouth anymore.

psychotria_elata2

Once the mouth is open, the magic of the kiss is gone. Photo by Dick Culbert.**

After pollination, the flowers develop into blue berries that are easily spotted by birds, which disperse the seeds. As the hooker’s lips produces fruits through the whole year, it is an important food source for fruit-eating birds.

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ResearchBlogging.orgReferences:

EOL –  Encyclopedia of Life. Psychotria elata. Available at <http://eol.org/pages/1106123/overview&gt;. Access on March 5, 2017.

Silva, C., & Segura, J. (2015). Reproductive Biology and Herkogamy of Psychotria elata (Rubiaceae), a Distylous Species of the Tropical Rain Forests of Costa Rica American Journal of Plant Sciences, 06 (03), 433-444 DOI: 10.4236/ajps.2015.63049

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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:

equisetum_myriochaetum

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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ResearchBlogging.orgReferences:

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: Tree Tumbo

by Piter Kehoma Boll

Today I’m introducing one of the most bizarre plant species in the world. Found in the Namib desert, in Namibia and Angola, the Welwitschia mirabilis, usually simply called welwitschia or tree tumbo in English, is the solely member of the order Welwitschiales, a group of gymnosperms in the division Gnetophyta.

welwitschia_mirabilis

A specimen of Welwitschia mirabilis in Naukluft, Namibia. Photo by Sara&Joachim*

The tree tumbo has a unique appearance. The seedlings have two cotyledons (the original leaves produced by the seed) and later develop two permanent leaves that grow opposite (at right angles) to the cotyledons. These permanent leaves grow continuosly, reaching up to 4 m in length. While growing, the leaves split and fray into several straps and occupy an area of about 8 m in circunference around the plant. The stem is woody and the flowers appear on a central part called crown. The species is dioecious, meaning that male and female flowers appear in different plants. Pollination is usually carried out by insects.

Living up to 2 thousand years, the tree tumbo is a very peculiar desert plant. Its leaves are broad and very large, different from what is the rule in the desert. Its root system is also very shallow, not penetrating deep in the ground. It seems that most of the water used by the plant is captured by the leaves from the morning fog.

Although having a very restrict range, the tree tumbo is not (yet) and endangered plant, as its population is considerably large. However, due to its popularity, some areas attract collectors, and since its growth is so slow, it may eventually become a vulnerable plant.

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References:

Bornmann, C. H. 1972. Welwitschia mirabilis: paradox of the Namib Desert. Edeavour, 31(113):95–99.

Wikipedia. Welwitschia mirabilis. Available at <https://en.wikipedia.org/wiki/Welwitschia&gt;. Access on March 1, 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.

araucaria_angustifolia

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.

araucaria_angustifolia2

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.

araucaria_angustifolia3

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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ResearchBlogging.orgReferences:

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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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.

selaginella_willdenowii

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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Friday Fellow: Christmas Wreath Lichen

ResearchBlogging.orgby Piter Kehoma Boll

Celebrating Christmas (or whatever you call this time of the year), today’s Friday Fellow is another lichen. And the reason I chose it is because it is known as Christmas wreath lichen due to its red and green color.

Cryptothecia rubrocinta growing on Patagonula americana in Argentina. Photo by Wikimedia user Millifolium.*

Cryptothecia rubrocicnta growing on Patagonula americana in Argentina. Photo by Wikimedia user Millifolium.*

Scientifically known as Cryptothecia rubrocincta, the Christmas wreath lichen is found throughout the Americas, from the United States to Argentina, and usually grows on shady tree trunks. In mature specimens, three different color zones can be seen, a central grayish-green zone, an intermediate white zone, and an external red rim. The central zone is usually covered by red nodules which in some cases may hinder the visibility of the grayish-green color.

The red color is caused by a combination of a quinone, called cheidectonic acid, and beta-carotene, which together protect the organism from radiation and provides DNA repair.

Apparently, this lichen only reproduces asexually, thus not forming any sexual structures. For that reason, it was thought for some time that it could be a basidiomycete fungus, although most lichens are formed by ascomycete fungi. Nowadays, however, we know that it is actually an ascomycete. DNA extraction is difficult, though, because several microscopic fungi live inside the lichen, thus somewhat making it a very complex organism formed by several interconnected species.

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References:

Elfie Stocker-Wörgötter (2010). Stress and Developmental Strategies in Lichens Symbioses and Stress, 525-546 DOI: 10.1007/978-90-481-9449-0_27

Wikipedia. Cryptothecia rubrocincta. Available at <https://en.wikipedia.org/wiki/Cryptothecia_rubrocincta&gt;. Access on December 16, 2016.

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