Girdling, or the removal of a strip of bark around a tree’s outer circumference, is often used to study carbon relations. De Schepper and Steppe adapt an existing tree model describing water and carbon transport in order to evaluate the mechanisms behind girdling responses in 3-year-old oak, Quercus robur. Induced changes in stem growth are mathematically linked to changes in turgor, sugar and altered loading/unloading rates, and close agreement is found between measured and simulated results.
These are links from our Scoop It page between October 20th and November 7th:
Socotra island has been geographically isolated from mainland Africa for the last 6 or 7 million years. Like the Galapagos Islands, Socotra island is teeming with 700 extremely rare species of flora and fauna, a full 1/3 of which are endemic, i.e. found nowhere else on Earth.
Mould fungi can be found almost everywhere. Their success is due to their remarkable versatility: depending on external conditions, they can choose quite different lifestyles. Sometimes fungi can be very useful for plants. They can shield the plants from diseases and at the same time boost their growth. Genetic studies show that fungi can be used as an eco-friendly alternative to conventional fertilizers and plant protecting agents.
Improving diet diversity, quality and ecosystem sustainability. 1.6 billion people are overweight, 2 billion have micronutrient deficiencies, and 60% of the world's food energy intake comes from just three cereals, wheat, rice and maize. This presentation asks about the role of agricultural biodiversity in diets in the developing world: Improving diet diversity, quality and ecosystem sustainability.
For those of us in the temperate North, Autumn is here, the Fall is upon us, deciduous leaves are changing colour and the New England tourism season is in full swing. Chemists though they knew almost everything they needed to know about what makes those verdant hues transform into the reds, yellows, oranges and browns of autumn. It was "simply" the decomposition of the green, light-trapping pigment chlorophyll, the excretion of toxic metabolites into the leaves and the withdrawal of still useful nutrients. Simple? No so fast…
Most people have no use for poison oak, but a flood control agency is planting rows of the stuff along the Feather River, even providing irrigation to help it thrive.
They've also added wild roses and blackberries to add thorns, but why? It turns out plants make excellent security guards.
With changes in crop cycles, specialised seeds, deep ploughing and land with poor productivity being set aside, wild flowers have been driven to the edges of fields, where they struggle to survive. In the Paris area, a third of them have disappeared already and another third is threatened with extinction. The poppy is still abundant all over France, but corncockle and darnel, among others, are in a precarious situation.
Botanists started being worried in the 1960s, because the flowers are a good indication of biodiversity on farmland, and they provide food for many pollinating insects. In the long term losing these pollinators will damage farming itself, because even cereals need to be pollinated.
In the 1980s, work with bacterial cells showed that they have mechanosensitive channels, tiny pores in the cells membrane that open when the cell bloats with water and the membrane is stretched, letting charged atoms and other molecules rush out of the cell. Water follows the ions, the cell contracts, the membrane relaxes, and the pores close. Genes encoding seven such channels have been found in the bacterium Escherichia coli and 10 in Arabidopsis thaliana, a small plant related to mustard and cabbage.
A group of plants called the cycads show just how slippery the concept of the “living fossil” can be. Cycads look superficially like palm trees, but they belong to a very different group. They first appeared on the planet around 280 million years ago, but they really hit their stride in the Jurassic and Cretaceous period, between 200 and 65 million years ago. But their time would soon be over. Out-competed by flowering plants, and suffering from the decline of their dinosaur polliantors, the cycads started to disappear. Today, the cycads are a mere shadow of their former glory. There are just 300 species, commonly thought to have endured since their heyday in the dinosaur era. But Nathalie Nagalingum from the Arnold Arboretum of Harvard University has found evidence that this narrative is a fiction. The cycads are indeed an ancient group, but the living species aren’t much older than 12 million years. They would never have been nibbled by dinosaur teeth. Living? Yes. Fossils? Hardly.
The UK government has said that it will invest £7m to tackle tree diseases, amid fears that millions of trees could be lost unless urgent action is taken. The Tree Health and Plant Biosecurity action plan was launched as scientists confirmed the arrival of a deadly disease in England among urban trees. Phytophtora lateralis was recorded in Devon on a Lawson cypress, a popular species in parks and gardens. Ministers hope the plan will tighten biosecurity measures and protect trees.
Think that plants are defenceless? Think again.
Because a plant can't move away from predators, they've evolved to become fortresses, with a whole line up of defences from the obvious, like spines, to the subtle, such as poisons that render insects infertile. This article looks at some of the hidden plant defences against both pests and dieseases, and how plants can switch on defence-related genes. If you're thinking about applying to study biology at University, this will extend your knowledge and bring you further up to date with some contemporary ideas in the field.