Snowdrops

I was prompted to think a little more about everyone’s favourite early spring flower when I heard that a single snowdrop bulb of a new variety, Galanthus plicatus ‘Golden Tears’, bred by Joe Sharman of Monksilver Nursery has just sold for a record £1,850 at auction on eBay! Joe is no rookie at this – he also bred previous record breaker ‘Golden Fleece’, which sold for £1,390 in 2015.  

A little virtual digging soon reveals that people obsessed with snowdrops, known as galanthophiles, regularly pay three and four figure sums for a single plant.  I love snowdrops as much as anyone but have to admit that I find it quite difficult to differentiate between some of the most common naturalised species (Galanthus nivalis, G, elwesii and G. plicatus), let alone between the hundreds of garden sub-species, varieties and hybrids available. Spotting subtle differences in flower shape, petal markings and ovary colour can often involve lying prone on cold, wet soil – not my favourite February occupation! I have no idea what the snowdrops in my garden are, or even if they are all the same species. At the risk of sounding even more of a Philistine, I’m not sure I particularly like varieties such as Golden Tears, with large green marks on their outer tepals, and a bright yellow ovary. When the green parts of plants turn yellow, it’s usually a sign of nutrient deficiency or ill health!

Though woodland floors carpeted with Common snowdrops, Galanthus nivalis, might seem quintessentially English, snowdrops are not native to the UK but come originally from mainland Europe; from the foothills of the Pyrenees eastward to the Ukraine, and from Germany and Poland southwards to southern Italy, Albania and northern Greece. Linnaeus first described G. nivalis in his Species Plantarum in 1753 but it was introduced before this to the UK as an ornamental garden plant, perhaps as early as the 16th century, becoming gradually naturalised by the late 18th century. Funnily enough, I’ve never heard it described as invasive garden escapee!  A trip to Durham Wildlife Trust’s Hawthorn Dene to see the snowdrops is one of my great pleasures at this time of year but they are, in fact, evidence that a stately home with landscaped grounds once stood at the top of the dene.

Researchers at the Royal Botanic Gardens, Kew studying the impacts of climate change on our flora monitor the flowering time of snowdrops as one of 100 representative species in the gardens. They have found that, whilst in the 1950s Galanthus nivalis flowers usually opened around the end of February, over recent decades the flowers have appeared earlier and earlier, now often in January or even December. In light of this, it’s a good thing that snowdrops don’t depend on insects for pollination and mostly reproduce by division of their bulbs. They are notoriously fussy to establish from dry bulbs though – it’s much easier to divide clumps as soon as plants finish flowering and transplant them ‘in the green’. This certainly worked fine last year when I decided to start transforming my front ‘lawn’ into something more meadow-like.

Like many bulbs, snowdrops are toxic to deter herbivores and insects – a dormant bulb would otherwise be a tempting snack.  The bulbs contain carbohydrate-binding proteins known as lectins involved in cell recognition processes. When lectins bind to specific carbohydrates on cell membranes, those cells stick together and cannot function. Lectins are also found in high concentrations in some dry seeds; they are what makes us ill if we eat beans that have not been properly prepared by soaking and cooking or if we are unlucky enough to ingest the seeds of a castor oil plant (which contain the potent toxin ricin).

Snowdrop lectin (known as GNA – Galanthus nivalis agglutinin) binds to mannose sugars on cell membranes and is an effective insecticide against a range of beetles, bugs, butterflies and moths.  Because GNA can move across the insect gut epithelium, some of my colleagues at Durham university (Fitches et al., 2012) have experimented with using it as a carrier for other, even more toxic, insecticides such as the spider-venom peptide known Hv1a. Hv1a targets insects’ central nervous system but is not particularly effective when just ingested by a pest. The idea is that GNA-toxin fusion proteins could be used for crop protection, either by applying them as treatments to growing plants or by incorporating them into genetically engineered plants. The same GNA is being studied for its potential activity against HIV and other viruses.

Snowdrops, along with daffodils and snowflakes, also have a second string to their defensive bow; an alkaloid known as galantamine (or galanthamine). Galantamine inhibits acetylcholinesterase (AChE), which normally breaks down and recycles acetylecholine, the neurotransmitter involved in signal transmission between nerve junctions. However, this also gives galantamine important medicinal uses.  People with dementia often have low levels of acetylcholine, which is important for memory, thinking and reasoning.  By preventing its breakdown by AChE, galantamine can improve the function of nerve cells in the brains of people with moderate Alzheimer’s disease. Unsurprisingly, the first hint of snowdrops having medicinal properties comes from those regions where they are native.  Some ethnopharmacists find evidence as far back as the antidote used against Circe’s poisons in Homer’s Odyssey, but more recent observations record the use of wild snowdrops in Eastern Europe in the 1950s to ease headaches and to treat polio symptoms (Heinrich & Teoh, 2004). So snowdrops are not just a pretty face!

Fitches EC, Pyati P, King GF, Gatehouse JA (2012). Fusion to Snowdrop Lectin Magnifies the Oral Activity of Insecticidal v-Hexatoxin-Hv1a Peptide by Enabling Its Delivery to the Central Nervous System. PLoS ONE 7(6): e39389. doi:10.1371/journal.pone.0039389

Heinrich M & Teoh HL (2004). Galanthamine from snowdrop – the development of a modern drug against Alzheimer’s disease from local Caucasian knowledge. Journal of Ethnopharmacology, 92, 147-162.

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