Bloomageddon: seven clever ways bluebells win the woodland turf war
This article by , Lecturer in Chemistry, was originally published on . Read the .
The appearance of vivid bluebell carpets in British woodlands is a sure and spectacular sign of spring. Bluebells 鈥� 鈥� are Britain鈥檚 and particularly fine carpets attract visitors to well-known sites such as in London and in Powys, Wales.
'This is our patch.'Bluebells also form carpets without a wooded canopy 鈥� for example, on in Wales 鈥� and point to the locations of ancient forests, long after the trees themselves have vanished. This is because, unlike trees, bluebells have most of their biomass and reproductive organs (the bulb) below ground where they are better protected.
They certainly are worth treasuring. It is estimated that Britain is home to half the world鈥檚 population of bluebells. But they are now threatened by the introduction of the related , (Hyacinthoides hispanica), leading to hybridisation and loss of habitat. Once removed, it takes decades to establish a population of bluebells large enough to create the characteristic carpets.
They are beautiful flowers, but have you ever wondered how bluebells pull off an even more impressive feat: being in their flowering prime when other plants have only just started to grow? Here are seven of their cleverest tricks.
1) The cold triggers growth: While most plants require a number of hours above a certain temperature before they start growing again, bluebells are dormant during the heat of the summer. Instead, their when the temperature drops below 10掳C, allowing them to get a vital head start and be in full bloom when spring finally arrives.
2) They dig deep: Bluebells have , which pull the bulb deeper and deeper into the soil with every year of growth. This protects the bulb from frost, which starts from the soil surface, and temperature fluctuations, and provides better access to water in drought conditions.
Cool customer: bluebells start growing when the temperature falls.3) They use fructans as reserve carbohydrates: While most plants use glucose and build starch or cellulose, bluebells predominantly convert sunlight into fructose, . This adaptation allows them to photosynthesise at temperatures below 10掳C. The plant鈥檚 large bulb comprises up to 70% fructans, which fuels their winter growth.
Fructans also serve another purpose, minimising the formation of new cells and causing existing cells to elongate instead. This is an advantage because the plants can grow without biosynthesising all the material needed to make new cells. You can see the effects of this by looking at a bluebell鈥檚 leaves: at first, they are firm and upright, but gradually lose their rigidity as the cells elongate.
4) They spear through any obstacles: The leaves that emerge from the bulb are as close to each other as possible and shaped like a spear with a small, sharp tip. This allows them to find their way through any obstacle 鈥� both below and above ground. When the leaves start emerging in mid-winter, there tends to be a lot of dead leaf matter and other detritus lying on the forest floor. Having an arsenal of little spears is critical for punching your way through this into the sunlight.
Bloomin鈥� clever
Bluebells at the base of an old oak tree.
5) They cooperate: 鈥� symbiotic fungi. The fungi obtains carbon from the bluebell in exchange for nutrients, particularly phosphorus. Both parties win, thanks to their use of a .
6) 鈥nd compete: Phosphorus is an important resource for plants 鈥� and bluebells 鈥渒now鈥� it. As well as securing their supply of it with the help of mycorrhiza, they also restrict the supply available to other plants. They do this by , which can only be converted into a usable form with specialised enzymes. so they take up more than they need thus depriving other plants?
7) They shape their surroundings: Bluebells to optimally support their own kind while making it harder for other species to grow. As well as storing phosphorus in the form of phytate, and using fructans instead of glucose-based polymers, they quite literally win the turf war by carpeting the space above ground.
Publication date: 10 April 2017