Category: History

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Shades of blue, Tokyo style

The Human Flower Project reports on a DIY indigo-dyeing shop in the heart of Tokyo. A fine idea, for all sorts of reasons. It puts people in touch with a natural, plant-based dye and offers us a chance to talk about agricultural biodiversity and even plant biochemistry.

The Human Flower Project’s page shows a photograph of the source of indigo labelled Polygonum tinctorium, also known as Chinese indigo. I fondly remember visiting an indigo demonstration dyer near Toulouse, in France, that sourced the dye from woad, Isatis tinctoria. And then there’s the Asian (or true, sic) indigo, Indigofera tinctoria. Native American tribes apparently used other legumes closely related to true indigo for their blue dyes.

What they all have in common is the process to get the colour. Young leaves are mashed with water and then encouraged to ferment. That results in a greenish sludge. The fabric is immersed in the sludge and then hung up to dry. As the pigments oxidize, they turn blue, and expert dyers can control the shade of blue by adjusting the duration of the oxidizing step, and other factors. (Loads more information here.)

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It struck me that indigo would make a marvellous central topic for one of those the-entire-history-of-the-universe-as-seen-through-a-single-neglected-thing books. There’s revolt and revolution, trade wars, the origins of modern organic chemistry, mercantile colonialism, slavery and rice, and pretty colours. Kew contibuted its model of an indigo factory to the BBC’s history of the world in 100 objects, but the model does not seem to have been the subject of one of those wonderful broadcasts. A pal of mine did a book on madder, another brilliant dye; I couldn’t find anything similar for indigo (although there is plenty of woo). Publishers! I am available.

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Nibbles: Amazon agriculture, Livestock conservation, Chestnut redux, COP 10, Stone Age flour

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Nibbles: Milk-drinking, Diversity and stability, Indian sheep, Development of the African savannah, Teaching rice, Silk, Diverse diet, Huge phallic inflorescences

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Nibbles: Abalone, Yak, Forests, Mountain plants, Yams, Ulmus, Apple, Banana

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The revenge of history

Three papers today which look into the role of history in determining patterns of diversity, at the species and genetic level. I don’t have much time today, so descriptions will have to be quick and dirty for now.

In Molecular Ecology, Hoban et al. used microsatellites to genotype 29 populations of Juglans cinerea from throughout the eastern US. ((HOBAN, S., BORKOWSKI, D., BROSI, S., McCLEARY, T., THOMPSON, L., McLACHLAN, J., PEREIRA, M., SCHLARBAUM, S., & ROMERO-SEVERSON, J. (2010). Range-wide distribution of genetic diversity in the North American tree Juglans cinerea: a product of range shifts, not ecological marginality or recent population decline Molecular Ecology DOI: 10.1111/j.1365-294X.2010.04834.x)) They wanted to know whether the observed pattern of genetic diversity was best explained by the spread of the species from refugia after the last glaciation, by its recent dramatic decline due to a fungal pathogen, or by a core-vs-periphery effect. It turned out to be the first of these. One of the consequences is that southern populations are the most diverse, and should be the ones to be targeted for ex situ conservation in the face of the depredations of the fungus.

Meanwhile, over at the Journal of Applied Ecology, Reitalu et al. looked at species diversity in Swedish grasslands in relation to various aspects of management. ((Reitalu, T., Johansson, L., Sykes, M., Hall, K., & Prentice, H. (2010). History matters: village distances, grazing and grassland species diversity Journal of Applied Ecology DOI: 10.1111/j.1365-2664.2010.01875.x)) They found that distance to the nearest historical village was an excellent predictor of grassland diversity, integrating various management variables. Diversity peaked at 1-1.5 km from the nearest village, and declined thereafter with distance. This finding could be used to prioritize grasslands for conservation, and to devise appropriate management programmes, which should involve moderate grazing pressure.

Finally, again in the Journal of Applied Ecology, González-Varo et al. describe a somewhat retro study on the Mediterranean Shrub Myrtus communis in SW Spain using isozymes. ((González-Varo, J., Albaladejo, R., Aparicio, A., & Arroyo, J. (2010). Linking genetic diversity, mating patterns and progeny performance in fragmented populations of a Mediterranean shrub Journal of Applied Ecology DOI: 10.1111/j.1365-2664.2010.01879.x)) Working not only on the actual natural populations but also on progenies, they wanted to know the relative importance of the past and the present effects of fragmentation of populations on fitness. The past effects were represented by the genetic diversity of populations, the present effects by outcrossing rates. In contrast to the previous two papers, they found that the present is a better guide to conservation that the past. It was outcrossing rates that had the strongest effect on the fitness of progenies. The recommendation is for honeybee hives to be controlled in the vicinity of these populations, to foster a diverse assemblage of local pollinators, and thus increased outcrossing.

Great to see very clear conservation recommendations being made in all cases, solidly based on the results. It is not always so.