Tagged: cycads



Dioon

Diversification of Dioon in the Mexican transition zone

The Mexican transition zone originated from the overlap of the Nearctic and the Neotropical biotas. By analysing the genetic variation within the cycad genus Dioon, a relict Neotropical group, Gutiérrez-Ortega et al. test the association betweenthe diversification of Dioon with the biogeographic provinciality of the Mexican transition zone. The variation of two chloroplast DNA fragments and genome-wide single nucleotide polymorphisms reveals four Dioon lineages that are geographically structured. The reconstruction of the expansion of Dioon suggests that Dioon migrated along the mountain chains of Mexico. While dispersing towards their current distribution, each geographic region provided disparate ecological conditions that facilitated...

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Volcano

Plants and Pinatubo, Prestahnukur, Popocatépetl…

Plants are generally sessile organisms that, unlike their puny animal ‘cousins’, can’t get up and run away if the environment is not to their liking. Botanicals by-and-large put up and shut up. Accordingly, that fundamental fact of their existence has led them to adapt to a remarkable array of abiotic factors, e.g. temperature, drought, high light levels, low light levels, excess UV, salinity, fire, heavy metals, herbivory, etc. Yet, however long and imaginative that list may be, what are the chances that you would have included volcanoes (ruptures on the Earth’s crust “that allow hot lava, volcanic ash, and gases...

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Odour emission, thermogenesis and pollination in cycad cones

Push–Pull Pollination

Cycads know a thing or two about pollination – that’s one reason they’ve been around since the Jurassic period. They are found across much of the subtropical and tropical parts of the world and many can survive in harsh conditions, from semidesert climates to wet rain forest conditions. All cycads are dioecious, and insect pollinators have to visit both male and female plants for pollination to occur. Effective pollination requires pollinators to move from male to female cones or to move back and forth between the male and female cones. The known pollinators of almost all cycads are insect herbivores...

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