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Yes, you've read correctly. Whist hopes remain high that the ‘white knight’ of genetic modification (GM) will drive a new green revolution delivering food aplenty, there are still groups looking at non-GM approaches to crop improvement. One such initiative, funded by the UK's BBSRC and a ‘fertiliser company’ (intriguingly unnamed in the press release) aims to ‘biofortify’ cabbages, broccoli and related crops such as pak-choi by boosting their content of essential human nutrients such as magnesium and calcium. Since such foods in the UK provide less than 10 % of our calcium and magnesium intakes, relatively small increases in their nutrient levels could provide significant benefits to health. It is anticipated that suitable increases can be achievable by improving fertiliser use and breeding programmes, and one of the goals of the research is to devise a recipe for a new type of fertiliser. Although based in the UK – and carried out by academic partners the universities of Nottingham and Warwick, Rothamsted Research and the Scottish Crop Research Institute (SCRI) – the work is expected to have world-wide relevance, potentially improving the diet of hundreds of millions. Not wishing to be sceptical but the nutrient improvement may be the easy part: getting children to eat their greens may prove more difficult!
You just couldn't make it up! Despite its undoubted beauty, for many years only negative thoughts were inspired by the site of water hyacinth (Eichhornia crassipes). Why? Because this Latin American beauty is a fast-growing, free-floating aquatic plant that has invaded water bodies far from its native home, particularly in Asia and Africa. When not controlled, the plant chokes waterways, reducing biodiversity and hindering water transport. It also provides an attractive habitat for malaria-carrying mosquitoes and snails harbouring the schistosomiasis flatworm. Now, however, it may get a new lease of life as a valuable source of fibre, courtesy of scientists at the Philippine Textile Research Institute (PTRI). They have made fibres from the plant's stem that can be blended with polyester to make clothing and domestic textiles. Although still a nuisance, the plant may yet prove a valuable source of income for communities who previously had nothing good to say about it. If only it could be grown in sufficient quantity … [http://www.scidev.net/en/news/water-weed-given-new-life-as-fabric.html]
Image: Wikimedia Commons/ARS.
For many years the forensic uses of plants and plant parts have helped to solve crimes like the infamous kidnapping and murder of aeronautical pioneer Charles Lindbergh's son in the 1930s. To a long list of uses we can now add another silent witness role as an environmental biomonitor. Researchers at Western Washington University in the USA have discovered that leaves along routes frequented by buses were up to ten times more magnetic than leaves on quieter streets. That magnetism comes from tiny air-borne particles of pollution – such as iron oxides from diesel exhaust – that collect on the leaves (primarily of bigleaf maple, Acer macrophyllum). The study suggests that tree leaves can be a simple and effective way to measure the load of particulate matter in the air. Being so small – less than 10 µm in diameter – the tiny particles bypass the airways and get deep into the lung tissues making them hazardous to human health. Inhaled particulate matter has been linked to issues such as breathing troubles and even heart problems. Whether the newly magnetic leaves could attract other metal-containing particles and effectively vacuum-clean the atmosphere remains to be explored, but the dual role of leaves as biomonitor and ‘bio-filter’ is a boon to denizens of mucky urban conurbations. [http://www.geosociety.org/news/pr/09-53.htm]
Image: SEM of small particles atop the leaf epidermis; Sadie Belica, WWU Geology.
Amid global economic collapses and financial calamities, what is a safe investment these days? Well, if funding for future food supply is what you need, then seed banks may save us all yet. The idea of saving seed is not new – many farmers do it regularly so they have seed from one year's successful harvest to sow for next year's. And the crucial work performed by such organizations as ICARDA (International Center for Agricultural Research in the Dry Areas) in holding stocks of land races of important staple crop species to re-introduce agriculture to war-ravaged parts of the world is also not new. But a long-term, deliberate stock-piling of the world's plant genetic diversity as some sort of safeguard against an uncertain future is a more recent endeavour. And arguably the most ambitious project is the Millennium Seed Bank partnership operated by the UK's Royal Botanic Gardens at Kew. It is the largest facility of its kind and contains the world's most diverse seed collections, and involves over 120 partners in 54 countries. Over the past 10 years, more than 3·5 billion seeds have been collected and stored, both in their country of origin and at the Seed Bank. A major milestone was recently achieved when it stored seed from its 24,200th species, a banana Musa itinerans – thus representing 10 % of the world's estimated total of flowering plant species. Given the undoubted importance of its work, it is rather depressing to discover that from 2010 the project will be unfunded. If it is to achieve its goals, Kew and its partners will need the support of governments, corporations and individuals [http://news.bbc.co.uk/go/em/fr/-/1/hi/sci/tech/8303753.stm]. In the interests of fairness, I'm sure the BBC would like us to point out that other seed vaults are available, e.g. that at Svalbard [http://en.wikipedia.org/wiki/Svalbard_Global_Seed_Vault].
Image: Millennium Seed Bank Building, Wakehurst Place, West Sussex, England; Wikimedia Commons.
Although many readers will be aware that the Annals of Botany is published by a corporate entity, this item has nothing to do with the company's shares being tradable on the New York Stock Exchange. Rather, it is recognition that it is now possible to access the journal's free Invited Reviews and Botanical Briefings, articles published under the Open Access agreement, and other articles 12 months after publication on PubMed Central (PMC). PMC is the ‘US National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature’; the Annals of Botany can be found at: http://www.ncbi.nlm.nih.gov/pmc/journals/442/. This single URL now offers users an alternative ‘one-stop shop’ for Annals of Botany free content.
Adenosine triphosphate (ATP) has long been known as the universal ‘biological energy currency’, with a central role in providing the energy that drives many chemical reactions within cells. In addition to that role it has an equally important function as an extracellular signalling molecule exchanging information between cells. Although better known in this regard in animal systems – e.g. in muscle contraction (reviewed in Scientific American December 2009: 84–92), recent work is beginning to unravel out-of-cell roles for e(extracellular)ATP in plants. Stephen Chivas and colleagues report (Plant Journal 60: 436–448, 2009) on a role for eATP in disease resistance and defensive signalling in plants. Using tobacco they showed that reduction in eATP levels was intimately linked to the expression of pathogenesis-related genes (themselves induced by a rise in salicylic acid levels). An old adage cautions us not to underestimate the importance of small things; such a pivotal role of ATP – whether intra- or extracellular – in determining life or death is testament to its wisdom and a good reason why energy levels should be boosted at all opportunities.
Image: Wikimedia Commons/Ben Mills.
It's always been a topsy-turvy world when feeding's concerned – what with vegetarian spiders and carnivorous plants – but upping the ante in the ‘who-eats-whom or what’ stakes, comes news of a true giant amongst flesh-eating plants. Whilst there are oft-repeated stories of carnivorous plants whose pitchers are large enough to drown rats, they are usually dismissed as myths or the far-fetched ramblings of those who have wandered too long in south-east Asian jungles. Now, however, it seems that there may well be truth in the stories. A new species of carnivorous plant has been discovered in the highlands of the central Philippines whose pitchers are big enough to catch rats as well as its more usual ‘prey’, insects. Of course, it is probably inaccurate to say that such a plant actually catches rats: it is conceivable that they fall in accidentally and drown in the pitcher's copious supply of liquid. As befits a giant in its field the plant has been named Nepenthes attenboroughii in honour of one of the UK's most internationally acclaimed naturalists and broadcasters, Sir David Attenborough (Botanical Journal of the Linnean Society 159: 195–202, 2009). The fact that the intrepid team of Stewart McPherson, Alastair Robinson and Volker Heinrich also discovered ‘strange pink ferns’ and blue mushrooms – which they could not identify – on their expedition does not detract from the magnitude of their insectivorous discovery. [http://news.bbc.co.uk/go/em/fr/-/earth/hi/earth_news/newsid_8195000/8195029.stm]
Image: Stewart McPherson, one of the plant's discoverers.
Love it or loathe it (it is difficult to remain unmoved by mention of its name), Arabidopsis is the most widely used model plant species. True, the best model for understanding corn is … corn, and the best model for understanding cassava is … cassava, but in terms of numbers of research groups using the tiny cruciferous weed and the investment in resources devoted to its study, its pre-eminence in that regard is surely undeniable. And you'd probably rightly expect that such an important organism would be suitably resourced so that those multi-national integrated studies into its biology could continue. Sadly, the continued existence of one of the main repositories of resources and information for Arabidopsis, TAIR (The Arabidopsis Information Resource) is currently under threat. The US National Science Foundation (NSF) is phasing out funding after 10 years as TAIR's sole supporter (Nature 462: 252, 2009). Whether or not an alternative source of funding can be found – advertising or subscriptions have been suggested – it demonstrates how sensitive everything is to a single provider. Acknowledging that the users of TAIR are multi-national – e.g. approx. 25 % are in the USA, 12 % in China and 10 % in Japan – it seems appropriate that an international funding solution is found. Notwithstanding a global credit crunch, given the importance of plant biology research to food and nutrition of a growing world population, surely any expenditure should be seen as a valuable – and essential – investment in the future of mankind, and a little philanthropy would not go amiss.
Image: Wikimedia Commons/Tim McCormack.
There comes a time when you think you've heard everything, what with magnetic leaves and plants that can catch rats, but vegetarian spiders? Surely, one of the things you can rely on is that spiders eat meat (some females go so far as to munch on their male partner after mating). Now we have a report (Current Biology 19: R892–R893, 2009) of a spider (Bagheera kiplingi) that is predominantly herbivorous. But, and as you might expect from those overly hirsute, multi-legged creatures, this is not your average honest-to-goodness, sweat-of-the-brow food-gathering vegetarian. Rather, the spider exploits the hard work put in by the mutualistic symbiosis between acacias and their ant guards in nibbling the specialized leaf tips (Beltian food bodies) the plant provides for its ant partners. OK, to do so it has to run the gauntlet of angry ants, but it seems a cheeky way of life to me. And if this item causes you even mild concerns about spiders (the vast majority of which are carnivorous), you may be interested to know that recently the UK's Royal Society of Chemistry has investigated claims that the seeds (‘conkers’) of Aesculus hippocastanum (horse-chestnut) may prevent spiders invading homes (http://www.rsc.org/AboutUs/News/PressReleases/2009/SpidersHateConkers.asp). The jury is still out on that one, and there is a suggestion that the wrong tree was used, apparently sweet chestnut (Castanea sativa) is the putative arachno-deterrent, and it is the wood not the seed that is important [http://prospect.rsc.org/blogs/rsc/2009/10/09/jon/are-spiders-scared-of-conkers/). Which just goes to show that the path to scientific enlightenment is a bumpy one. As a final aside, the leaf-munching spider is named after Bagheera, the black panther in the Jungle Book stories of Rudyard Kipling. Naming a vegetarian spider after a famously carnivorous big cat is another bizarre twist to an already odd story!
Image: R. Curry, one of the authors.
Ecology is all about scale, whether it be a 0·25-m2 frame quadrat, a rainforest or a whole planet – or even the surface of an individual leaf. Oft overlooked(!), but never totally ignored, leaves are probably the largest biological interface on the planet. Whilst we rightly celebrate them for the crucial role they play in removing carbon dioxide from, and releasing oxygen to, the atmosphere, and the not unimportant act of primary biomass production, we tend to forget they are also home to smaller organisms. The organisms that occupy this phylloplane (and surrounding phyllosphere) are numerous and engage in many-fold interactions with the leaf, and hence the plant and planet. Some are major plant pathogens – e.g. fungi, bacteria, viruses – and rather than appear as a pleasant green lawn of tranquillity, leaf surfaces should more properly be viewed as amphitheatres where plant versus all-comers combat is carried out. Quite how numerous and diverse are the species supported by the leaves has been made clearer by work of Delmottea et al. (PNAS 106: 16428–16433, 2009). Looking specifically at the physiology of non-pathogenic leaf-dwelling bacteria in soya, clover and Arabidopsis, they used a ‘community proteogenomic’ approach (which does not examine individual species but looks at the extracted massed protein and DNA sequences to make inferences about the taxonomic variety present in the sample). As a result they discovered proteins for using methanol (a plant waste product), which were assigned to Methylobacterium species; amino acid transporters enabling use of plant-derived nitrogenous compounds; porins, which appear to be involved in carbohydrate uptake in Sphingomonas; and proteins that may have an adhesive role. Much still remains to be done, but continued investigation of the complex ecology of this most important of habitats could benefit many biological disciplines, not least those that aim to understand global cycles of carbon and nitrogen.
When we consider essential nutrients we are usually concerned with individual species. For example, it is generally regarded that higher plants need 17 essential nutrients: C, H, O, P, K, N, S, Ca, Mg, Cl, Fe, B, Mo, Zn, Cu, Mn, Ni; some – e.g. halophytes or CAM plants – require additional elements such as Na to function. But research by Kaspari et al. (PNAS 106: 19405–19406, 2009) takes the idea of essential nutrients far beyond individual species to consideration of an ecosystem. They found that sodium had a dramatic effect on the rate of cycling of carbon in an inland tropical Amazonian rainforest. Adding NaCl solution (‘seawater’) to the leaf litter enhanced loss in mass by 41 %, decreased lignin concentrations by 7 % and enhanced decomposition of pure cellulose by up to 50 % compared with stream water alone. Although this is largely ascribed to the importance of sodium for the functioning of detritovores and herbivores – such as termites, whose numbers increased 7-fold – it does show an ecosystem-wide effect of an element and provides experimental evidence that its shortage slows the carbon cycle. With 80 % of global landmass >100 km inland, carbon cycling may frequently be regulated via Na limitation. Arguably, however, decelerating the decomposition of wood slows the release of its stored carbon back into the atmosphere, so from a global warming point of view salt-limitation may help to reduce climate change. But, if the climate change occurring at present causes sea levels to rise sufficiently, then more inland forests may be within reach of the sea-salt's malign influence, which could feed-forward to accelerate carbon release to the atmosphere, which may cause more sea level rise. Complex things these large-scale feedback–feed-forward interactions!
Image: Wikimedia Commons.