Tagged: weeds





Bidens pilosa

Achene heteromorphism in Bidens pilosa (Asteraceae): differences in germination and possible adaptive significance

Bidens pilosa L. (also known as cobbler’s pegs, farmer’s friend and burr marigold) is a noxious weed in many ecosystems worldwide. Across China, the plant can be found growing on roadsides and in fields and villages at elevations below 2500 m. It produces large numbers of heteromorphic (central and peripheral) achenes that differ in morphology, with the central being long and the peripheral short. In terms of ecophysiology, it was observed that peripheral achenes remain attached to the receptacle longer than central ones. There is however very little known about the germination strategies of these dimorphic achenes. Annual plants survive by...

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Simplified phylogeny of the green plant lineage focusing on the occurrence of WGD (whole-genome duplication) events

Polyploidy and interspecific hybridization shape adaptation, speciation and evolution

About half of all higher plant species are recognizable as evolutionarily recent polyploids, where multiple whole genomes or sets of chromosomes have come together from close ancestors. Additionally, over evolutionary time, all flowering plants have at least one polyploidy event, also known as a whole-genome duplication (WGD), in their ancestry, from before the divergence of gymnosperms and angiosperms, the ζ (zeta) event (see the legend in the paper for the many references). This Annals of Botany Special Issue on Polyploidy in Ecology and Evolution presents the evolutionary consequences of new, recent, and ancient polyploidy. Alix et al. survey experimental, genomic,...

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Image: Wikimedia Commons.

Scaring the crows…

One way of increasing crop productivity is to increase the amount of grain or other harvestable product that is actually harvested from the plant. To that end scarecrows  were invented by human beings, although their success in that regard is inconsistent at best (is there a scientific study on the effectiveness of scarecrows just waiting to be done..?). However, another variation on the scarecrow theme aims to tackle productivity more directly, and shows quirkily that clues to above-ground productivity can come from ‘down-below’. Investigating any similarities between the endodermis in roots [‘the central, innermost layer of cortex in some land...

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Image: Wikimedia Commons.

Arabidopsis must die(?)

It looks like somebody has taken the Danish advice to obliterate weeds in my previous item too far in producing a list of ‘The top 10 ways to kill arabidopsis’. Now, I know that for many of us Arabidopsis is a weed (after all its common name is l’herbe mauvais – allegedly – in French), but even I acknowledge that it does have important plant biological uses. So, before the arabidophiles amongst my legion of adoring fans reach to turn the flamethrower or pan of boiling water on me, I ought to explain that the full title of that list...

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Image: From the Synopsis of Histories by John Skylitzes, 12th century.

Extreme thermal weed control

Ever mindful that we ought to pursue environmentally friendlier methods where at all possible, I’ve been scouring the literature on your behalf. Well, a search for a ‘greener’ method of weed control may have ended with Anne Merete Rask’s recently defended University of Copenhagen (Denmark) PhD thesis entitled ‘Non-chemical weed control on hard surfaces: an investigation of long-term effects of thermal weed control methods’. Rather than use nasty chemicals, the research proposes that hot water/steam or heat should be used to ‘deal with’ those pesky plants (aka ‘weeds’) in hard-surface situations (i.e. not your typical arable setting). But you won’t...

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Smoking out weeds with karrikinolide

Smoking out weeds with karrikinolide

Karrikinolide (KAR1) is a smoke-derived chemical that can trigger seeds to germinate, and shows promise as a tool for flushing out weed seeds from the soil seed bank. Long et al. demonstrate that weeds of Brassicaceae are particularly responsive to KAR1, and that  these responses are complex and transient: light and temperature conditions, dormancy state and seed lot all influence sensitivity to KAR1, and a response to KAR1 can be induced. Three ‘response-types’ are proposed for assessing the effects of KAR1 on seeds: inherent, inducible and undetected. All 15 seed lots in this study fall into the first two categories, so KAR1 has a clear potential...

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