Image: Wikimedia Commons.
There is a widespread belief that everything in/of/from/about America is bigger, better, faster, etc, than anything from elsewhere in the world. That is probably the best example of spin over substance ever foisted on an unsuspecting world, and is a true testament to the power of marketing and public relations.
Take, for example, the arresting title ‘This Could Be the Oldest Flowering Plant Ever Found in North America’. So prevalent is that view of American supremacy and so conditioned are we to its acceptance that many of us will have read that text and mentally added a comma after the words ‘ever found’ (and the importance of comma placement is legendary). The news story concerns a re-assessment of fossil plants stored away in the USA’s Smithsonian National Museum of Natural History. Originally thought to be a fern, reinspection and analysis by USA-based Nathan Jud and Leo Hickey now confirms that the fossil is an angiosperm (a flowering plant) between 125 and 115 million years old (Ma) – the Lower Cretaceous – named Potomacapnos apeleutheron.
While this is amongst the oldest flowering plants found in America, it is not the oldest known on Earth. That honour goes – currently! – to the unnamed bearers of ‘angiosperm-like pollen’ and the described genus Afropollis from Middle Triassic deposits in Switzerland that are 247.2–242.0 Ma, as unearthed by Peter Hochuli and Susanne Feist-Burkhardt. The pollen was studied using confocal laser scanning microscopy (CLSM), exploiting the autofluorescence still present in such ancient organic-walled microfossils. Quite dramatically, this announcement pushes back the origin of flowering plants another 100 Ma into history, which must be rather gratifying for the Swiss–German team. So, whilst national self-belief is a good thing to have (rather like patriotism), it mustn’t blind us to the fact that other countries may have more legitimate claims to ‘biggest and best’ (and which might stray into nationalism). And anyway, it’s only because of ‘accidents of history, geography and politics’ that scientific discoveries are tied to a particular place and claimed for, and/or by, individual countries. Science – and its discoveries – belongs to us all. There, I’ve said it (and with flowers…).
[As usual, Mr Cuttings has tried to be a little mischievous in this item. But it probably won’t halt the activities of those whose lifelong goal is to seek out the biggest, best, etc, so expect further archaefloral revelations from the good old US of A in due course (and maybe further afield…), as more store-rooms replete with rocky riches are rummaged through, re-examined, and re-assessed! And if a good bit of healthy, old-fashioned competition and rivalry can spur on all those engaged in the process of science to even greater things, then so much the better – for us all! – Ed.]
Image: Taro Taylor/Wikimedia Commons.
It’s a tribute to the fantasticness of plants – and photosynthesis in particular – that even animals want to be like them. Arguably, none more so than some sea slugs, which for many millennia have eaten seaweeds and integrated their chloroplasts into their bodies (a phenomenon known as kleptoplasty). The assumption that underlies such acquisitive behaviour is that the new owners use those sequestered verdant powerhouses as a fuel source for their own purposes. A lovely idea – and one that will have found its way into the textbooks, and featured in lectures based thereon. But! Gregor Christa et al. have concluded that, while such ‘stolen plastids’ display light-dependent CO2 fixation (i.e. photosynthesis), light is not essential for the studied sea slugs – Elysia timida and Plakobranchus ocellatus – to stave off starvation. Indeed, they conclude that the internalized plastids seem to be a slowly digested food source rather than a source of solar power. In other words, this is an example of plants feeding the planet (again!). However, another bonus of this work is that animals are still just animals and not proxy plants. Which is good, because, to paraphrase one Harold Woolhouse, if one wants to understand the biology of plants one will ultimately have to work on… plants.
[However, if you wish to study animals that penetrate each other in the head during sex, then that’s where sea slugs really come into their own. But if you want more on photosynthetic animals, check out this article by Sarah Rybak – Ed.]
Image: Britton & Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. Charles Scribner’s Sons, New York.
Schadenfreude (taking pleasure in the misfortunes of others) is not the most attractive of human traits, but it can be so satisfying. And I bet there’s more than a little of that throughout the world occasioned by the discovery that the model plant Arabidopsis thaliana seems not to be such a good model after all. And the reason for this global wave of ‘arabidisenchantia’ relates to a rather fundamental property of cells known as nonsense-mediated mRNA decay (NMD). NMD is a so-called surveillance pathway that reduces errors in gene expression by eliminating aberrant m(essenger)RNAs that would otherwise encode incomplete polypeptides. Important though this process is for cell survival, it had been assumed that plants used it in a different way to animals because a gene for a key protein – SMG1 (phosphatidylinositol 3-kinase-related kinase) – in the pathway had not been identified in Arabidopsis thaliana (afka* ‘the universal plant’), nor in fungi. However, and thanks to iconoclastic (albeit probably unintentionally) work by James Lloyd and Brendan Davies, we [arabothalocentric plant biologists and those who needs must rely on their abundantly-funded researches - which is pretty much all of the rest of us...] can all sleep more soundly in our beds. They show that SMG1 – the gene that codes for SMG1 – is not animal-specific, but is found ‘in a range of eukaryotes, including all examined green plants [my emphasis] with the exception of A. thaliana’. The misconception about the importance of SMG1 in plants appears to have arisen because the gene was lost from A. thaliana ’s genome 5–10 millions of years ago. Interestingly, SMG1 is found in the genome of the closely related A. lyrata… So, A. thaliana is unique after all(!), though not in quite the way its promoters (pun intended…?) might have liked. But if thale cress has carelessly lost this gene, what else has it lost (but which may have been retained by more typical plants)…? I predict more Arabidopsis applecart-upsetting in the future…
* afka = as formerly known as…
Image: Robert A. Rohde/Wikimedia Commons.
Many abiotic variables affect plants, e.g. levels of light, carbon dioxide and water. One of the most important of those non-biotic factors is temperature. Now, given its importance you could be forgiven for assuming that it is recorded accurately and correctly. Unfortunately, that isn’t always the case. Take for instance the temperature of the meristem (symbolised as Tmeristem), which is important in driving plant development. For such a crucial aspect of plant biology studies have largely relied on measuring the temperature of the air surrounding the plant (Tair). Tair is measured because it is assumed to represent the meristem temperature because plants are poikilotherms (organisms whose ‘internal temperature varies considerably … Usually the variation is a consequence of variation in the ambient environmental temperature’). Whilst that assumption may seem reasonable – and it does save the would-be investigator the trouble of penetrating the umpteen layers of developing leaves, etc, that may sheathe the apical meristem, it is nonetheless an assumption. And the veracity of assumptions must be tested, which is what Andreas Savvides et al. did. Guess what they found! That’s right: Tmeristem differed from Tair – ranging between –2.6 and 3.8 °C in tomato, and –4.1 and 3.0 °C in cucumber(!). As the team conclude, ‘for properly linking growth and development of plants to temperature… Tmeristem should be used instead of Tair’.
If you’re now intrigued by detecting temperatures within cells, you might like to explore the nanoscale thermometer developed by G. Kucsko et al. Using ‘quantum manipulation of nitrogen vacancy (NV) colour centres in diamond nanocrystals’ it can detect temperature variations as small as 44 mK(!) and can measure the local thermal environment at length scales as low as 200 nm(!!). Or, if you want a more biological approach, check out the genetically encoded sensor that fuses green fluorescent protein to a thermosensing protein derived from Salmonella, as showcased by Shigeki Kiyonaka et al. Although proof of this particular principle was demonstrated with thermogenesis in the iconic mitochondria of brown adipocytes (and the somewhat less iconic endoplasmic reticulum of myotubes), the team envisage it could be used to investigate this phenomenon in other living cells. Maybe even within the cone cells of tropical cycads that undergo impressive increases in temperature, where Tcone can be markedly greater that Tair. In view of concerns about global temperature changes and effects of temperature on regulation of such economically important processes as flowering, accurate temperature information in planta – and an appreciation of the temperature that plants are actually responding to – is likely to become increasingly important.
[For a useful set of slides summarising Savvides et al.’s work, visit slideshare.net. For a less physics-oriented interpretation of the Nature nanoscale thermometry article try the accompanying ‘News and Views’ item by Konstantin Sokolov – Ed.].
Image: Archie Portis/Wikimedia Commons.
The ability of plants – and other plant-like organisms that aren’t in the Plant Kingdom (such as the Protists, algae and seaweeds, and the prokaryotic Moneran cyanobacteria) – to manufacture their own organic food from the simple inorganic materials carbon dioxide (C and O – two nutrients in one!) and water (H and O; ditto) using light energy in the process known as photosynthesis never ceases to amaze. But there are those who need to be reminded of how amazing photosynthesis is, and how fundamental green things are as the conduit by which energy is converted from a physical, electromagnetic form to a chemical form that is then available to the plants, and all those organisms who consume them (whether directly or indirectly).
One way we’ve often done this is to impress upon our students the importance of Rubisco, Ribulose-1,5-bisphosphate carboxylase-oxygenase, the enzyme that ‘catalyzes the primary chemical reaction by which inorganic carbon enters the biosphere’ in photosynthesis, with statements such as Rubisco is the ‘most abundant protein on Earth’. (And which represents a major sink for another essential nutrient – nitrogen (N), an essential component of amino acids from which such proteins are made…) Impressive, certainly, but is such a statement accurate? Well, examining that enzyme in single-celled marine algae, Jenna Losh et al. conclude that ‘unlike in plants, Rubisco does not account for a major fraction of cellular N in phytoplankton’ but constitutes less than 6% of total protein in those microalgae (cf. up to 50% in ‘plants’).
What might one conclude from this? We must try to avoid terrestrial bias in our plant biology! Whilst members of the Plant Kingdom might dominate terrestrial biomes, non-Plant Kingdom members are the major photosynthetic organisms in aquatic habitats, which occupy more than two-thirds of the Earth’s surface. Oh, and never ignore the small things!
We often hear that money doesn’t grow on trees. And on one level that is patently true. However, on another it may have the ring of truth. For example, if the tree in question makes a compound with useful medicinal properties then its exploitation may lead to the generation of profits for those who grasp that opportunity. Aha, so you might think we are talking about development of aspirin, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication derived from salicin found in such trees as willows, or the bitter-tasting, antipyretic, antimalarial, analgesic, anti-inflammatory alkaloid quinine from trees of the genus Cinchona. Not on this occasion.
Nauclea latifolia. Photo by Scot Zona. CC BY.
Rather, we are here concerned with work by Ahcène Boumendjel et al., which has demonstrated the presence of (1R,2R)-rel-2-[(Dimethylamino)methyl]-1-(3-methoxyphenyl) cyclohexanol in root bark of the sub-Saharan shrub Nauclea latifolia, commonly known as African peach or pincushion tree). That gloriously named organic compound is a centrally acting opioid analgesic used to treat moderate-to-moderately-severe pain and is more commonly known as the commercially important drug Tramadol.
Sounds ‘useful’? Yes. However, the real significance of the discovery isn’t of ‘yet another pain-killer provided by nature, aren’t plants great’, but the fact that tramadol is a synthetic molecule previously only known as one of human invention and design. Although this study is apparently the third reported case of the occurrence of a synthetic and clinically-used drug in natural sources, it is the first documented instance of the occurrence of such a drug at clinically relevant concentrations in a plant source (to the best of the authors’ knowledge). That nature seems perfectly capable of producing it on its own begs the question of how many other human-created drugs might exist in other plants. Perhaps perchance a putative, plentiful phytological pharmacopeia patiently awaits? And another reason to marvel at the biosynthetic abilities of non-sentient organisms that haven’t spent years learning their craft at pharmacy school. Good – and timely – news also for the relief of the pain of hangovers that often accompany those imbibitionally indulgent parties that accompany such major post-New Year events as 25th January’s Burns’ Night?
[Rumours that Nauclea saplings can only be purchased from garden centres against a physician-authorised prescription are just that. Neither Mr Cuttings nor the Annals of Botany condone experimentation with, or self-administration of, extracts of Nauclea – Ed.]
Nauclea latifolia by Scott Zona/Flickr. This image licensed under a Creative Commons by licence.
Image: Hans Stieglitz/Wikimedia Commons.
‘That which does not kill us makes us stronger’ are words attributed to Friedrich Wilhelm Nietzsche, a German philosopher who was much-admired by certain charismatic individuals with ‘leanings towards European domination’ in the first half of the 20th century (yes, that one, with the Chaplinesque moustache and a personal ‘struggle’…). And those words have already been discussed on the Annals of Botany blog site in connection with snails, where Herr Nietzsche’s famous pronouncement was allegedly disproven (botanists are a philosophical bunch…). Well, and in support of the moustachioed Prussian’s statement, we now share this example with you botanical blogtrotters. Studying feeding behaviour of the gemsbok – a large antelope found in the arid regions of southern Africa – David Lehmann et al. showed that 25% of the inferred (from stable isotope ratios of potential food sources and three types of tissues – blood, liver and muscle – from the antelope) diet of these grazers consisted of Euphorbia damarana. This spurge is a CAM (Crassulacean Acid Metabolism) plant that is endemic to the study region in Namibia and is rich in toxic secondary plant compounds – so rich, in fact, that its milky latex is allegedly capable of killing human beings. Clearly, what didn’t poison the gemsbok made them stronger under those challenging environmental conditions. This is also a good illustration of why one can’t rely on the feeding habits of AN Other species as a guide to what may be OK for humans to eat! However, as interesting as that is, I think the more remarkable discovery is that gemsboks feed almost exclusively on C4 and CAM plants at other times when food is plentiful. How can they tell C4/CAM from C3 photosynthesisers? What an amazingly good knowledge of plant photosynthetic biochemistry they must have to enable such a sophisticated degree of discernment!
Eating bad things to keep you well is one thing, but getting ill from eating things supposed to make you better is quite another, and is exemplified in research into aristolochic acids (AA), ‘a family of carcinogenic, mutagenic, and nephrotoxic compounds commonly found in the Aristolochiaceae family of plants, including Aristolochia and Asarum (wild ginger)…’. Plants containing AA have been widely used in traditional Chinese herbal medicine, and – despite the link having been demonstrated between a rapidly progressive renal disease and consumption of AA-containing Chinese herbs (and which is now termed aristolochic acid nephropathy) – such plants are still in use worldwide. It is to be hoped that the latter’s review of the subject will help to raise awareness of the problem and contribute to more intelligent use of the healing powers that do reside within plants.
[Ed. - Interestingly, in PNAS Julia Lee-Thorp et al. show that Pliocene hominins (ancestral humans...) also seem to have had the ability to discriminate in favour of C4 plants in their diet...Which gives a great trivial pub quiz question: What is the connection between gemsbok and ancient humanoids..?]
Image: Alberto Salguero/Wikimedia Commons.
In case you missed this, here’s news of a charming series that aims to present vignettes of current plant science research and researchers within a broader educational remit of promoting the importance of basic plant science. As such it could be useful for impressing upon those supposedly impressionable early-stage undergraduates the relevance of phytology, and might also have a role to play in wider outreach evangelising of the importance of plant biology. Anyway, this first – of many? – in the series showcases the work of Siobhan Braybrook, Career Development Fellow at the University of Cambridge’s Sainsbury Laboratory. Penned by Siobhan, it explains her fundamental work on aspects of plant development – including the important role of pectin in determining cell wall expansion – and discusses why such basic plant science is value for money. A little gem from GARNet (a sponsored network that supports arabidopsis researchers and the wider plant community).
[GARnet is in turn sponsored by the BBSRC (Biotechnology and Biological Sciences Research Council), a major UK government-funded sponsor of biological research. Another ‘importance of basic plant science’ item you might be interested in is the University of Cambridge’s Professor David Baulcombe’s keynote talk from the UK PlantSci 2013 meeting.
`Image: Wikimedia Commons.
The importance of green chlorophyll to photosynthesis has been established for many years (so much so I’m not even giving a link to support this contention). But just because a tissue is green does that mean it must be photosynthetic? And if so, does it follow that the degree of photosynthesis undertaken must be ‘significant’? If one answers yes to the first of those, one could argue that experience of other green, photosynthetic situations supports the view that others will be too – the predictive power of science. If one answers yes to the latter, one is not really being that scientific, which ought to be evidence-based (at the very least; botany is after all an ‘ology’!).
In true scientific tradition, the importance of photosynthesis in green nectaries has been examined by Ulrich Lüttge. Nectaries are glandular structures that secrete nectar (‘a sugar-rich liquid’ with major ecological and economic importance and relevance), and which may be located on flowers – floral nectaries – or on other plant parts – extrafloral nectaries. Although there has been a general assumption that photosynthesis by such structures can supply the carbohydrates secreted in the nectar, to date quantitative data on their photosynthetic capacity has been largely missing. Cue Lüttge’s work, which examined 20 floral and six extrafloral nectaries from a range of plant taxa. Whilst the photosynthetic parameters measured were lower for nectaries than their corresponding leaves, the accompanying quantitative analysis supported the contention that photosynthetic activity of green nectaries can explain a significant part, if not all, of the sugar secreted. A nice example of not taking anything for granted (even if the original assumption is not overturned, it is at least now substantiated!).
[This work chimes timely with recent studies devoted to aspects of the ecology and evolution of extrafloral nectaries in Brigitte Marazzi et al.’s Viewpoint article entitled ‘The diversity, ecology and evolution of extrafloral nectaries: current perspectives and future challenges’. For more on non-foliar photosynthesis generally, check out this review by Guido Aschan and Hardy Pfanz – Ed.]
Image: Steve Hopson/Wikimedia Commons.
The answer to that schoolboy question used to be ‘shark-infested custard’. Now, though, it seems it’s simply ‘bananas’(!). To explain, Paul Grant et al. have detected high levels of many pesticides in the blood of spectacled caimans – freshwater alligatorid crocodylians (reptiles that are like alligators and crocodiles) – in Costa Rica. Whilst the caiman don’t eat bananas, the cocktail of pesticides within the carnivores is inferred to have originated from banana plantations upstream of the caimans’ area, and to have contaminated the waterways that the reptiles inhabit. Caiman pesticide concentration decreased with distance from the intensively managed banana plantations – ‘high-intensity banana crop watershed of Rio Suerte’, and their body condition was negatively correlated both with total pesticide concentrations and with proximity to banana plantations. Both of which findings support the views that pesticides may have led to toxic effects in the caiman, either directly, impoverishing their overall health, or indirectly, via pesticide effects on the quantity or quality of their prey.
Concerns are raised on many levels. The caimans inhabit the Tortuguero Conservation Area: how should conflicts between economics and development on the one hand – bananas are a major income generator for Costa Rica – and conservation on the other be managed? Many of the pesticides found in caiman include insecticides categorised as Persistent Organic Pollutants (POPs), which are banned under the 2011 Stockholm Convention: why are such compounds being used? In a rather understated way the abstract concludes thus: ‘…results indicate that pesticide use in banana plantations is impacting a high trophic level species inhabiting one of the most important wilderness areas in Costa Rica (Tortuguero National Park)’. Whilst this is not the place to solve those problems, we can at least air them, and this example does make the point that botany can impact upon many areas of life. Bananas, food for thought (and caimans, a biomonitor with real teeth!).
[Not wishing to be overly picky, but I do note that the journal’s abstract shows several zero probabilities for the results of certain statistical tests, e.g. ‘F = 20.76; p= 0.00’. Hmm, a terminal digit missing methinks. But, maybe that’s what happens when you get too close to a crocodilian..? – Ed.]