Archive for the ‘Botany’ Category

How tall can a tree grow?

June 30, 2011

The world’s tallest tree is found in northern California – it’s a redwood that stands 115 meters (379 feet) tall. This tree and its relatives are the largest single organisms in the world, but just how big can these trees really get?

Trees might go on growing forever if it wasn’t for gravity. The higher up trees grow, the more energy is needed to transport water from the root system to its leaves up top. That means the leaves will get smaller and smaller, until the amount of energy they can gain from photosynthesis is outweighed by the energy expended in order to haul up water in the first place. At that point, there’s no point for the tree to keep growing, and it stops.

So what, precisely, is the upper limit for the world’s biggest trees? According to biologists, the cutoff point is somewhere between 122 (400) and 130 meters (426 feet). Learn more here.

How green is the Earth really?

June 19, 2011

This is the first map ever produced that shows the global output of plant fluorescence. That means you’re seeing the most realistic representation of healthy plant life across the entire face of the Earth.

This map is also a reminder of just how green our planet still is.

As part of their natural life cycle, plants convert light into energy in a process called photosynthesis. Essentially, they eat light. During this process, leaves emit a faint, reddish glow that scientists call plant fluorescence – and detecting it is a helpful way to measure the health of plants across wide patches of landscape. Learn more here.

Plants can feign illness

April 3, 2011

Aside from an active social life, plants display a whole range of other human-like behaviours.

The elephant’s ear Caladium steudneriifolium is prone to infestations of mining moth larvae: once hatched, the caterpillars eat their way through its leaves. To prevent this, plants can feign illness, displaying a white variegation pattern on their leaves which resembles recent larval damage. Preferring to exploit a healthy plant, the moths lay their eggs elsewhere.

The leaf on the left shows real predation, whereas the one on the right has been variegated by the plant to mimic it. Read more here.

Botanic gardens spread plant invaders

March 22, 2011

Botanic gardens are generally well-tended parks displaying a wide range of plants labelled with their botanical names. They may contain specialist plant collections such as cacti and succulent plants, herb gardens and plants from all around the world.

Unfortunately, it turns out that more than half of the world’s most invasive plant species spread into new habitats from botanic gardens, an analysis of historic “alien” escapes has concluded. Although most cases analysed happened between the 1800s and the mid-1900s, there are reports of more recent releases which merit a tightening up of biosecurity, researchers warn.

Plant species can escape from specialist gardens through waterways, wind dispersal and animal transportation. Once in the wild they can invade and take over native habitats. Read more here.

Poisonous pitcher plant

February 15, 2011

As we know knowPitcher plants are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap. Check it out:

Biodiversity is very important

February 11, 2011

The first evidence that the loss of a bird species could damage the prospects of particular plants has heightened fears for vulnerable plants around the world.

Many plants rely on birds to pollinate them and disperse their seeds, so it seems reasonable to assume that if the bird population falls, this will have a knock-on effect on plant species. Now the effect has been seen in a shrub (Rhabdothamnus solandri), following the extinction of two birds – the bellbird (Anthornis melanura) and stitchbird (Notiomystis cincta) – on New Zealand’s North Island after rats were introduced there in the 1870s.

Plant extinctions tend to be slower than animals, because plants live longer. As such the shrub is not yet extinct. But since birds are responsible for pollinating a large proportion of flowering plants, the problem is likely to be occurring all around the world.

Biodiversity is very important! Read more here.

Plants are fighting with spiders

May 19, 2010

Interspecific competition, in ecology, is a form of competition in which individuals of different species vie for the same resource in an ecosystem (e.g. food or living space). The other form of competition is intraspecific competition, which involves organisms of the same species.

If a tree in a dense forest grows taller than surrounding trees, it is able to absorb more of the incoming sunlight. However, less sunlight is then available for trees that are shaded by the taller tree, thus interspecific competition. An example among animals could be the case of cheetahs and lions; since both species feed on the same prey, they are negatively impacted by the presence of the other because they will have less food. Also, lions sometimes steal prey items.

Closely related species often compete aggressively for resources. But researchers have now found a remarkable exception: a plant competing for food with an animal.

The species in question are sundews and insect-eating wolf spiders. Sundews (Drosera capillaris) cover their leaves in a sticky mucous to trap insects and consume them with digestive enzymes, whereas the spiders (Sosippus floridanus) weave dense webs. Both species live close to the ground in the damp bogs of southern Florida, and both prey on a variety of bugs, including flies, ants, crickets, and springtails.

The scientists found that the spiders built larger webs when sundews were around than when they were absent. Conversely, sundews, suffering from limited resources, produced fewer leaves, seeds, and flowers. Read more here.

Plants can kill you

April 26, 2010

This is a picture of Actaea pachypoda. The plant grows to 50 cm or more tall and its most striking feature is its fruit, a 1 cm diameter white berry, whose size, shape, and black stigma scar give the species its other common name, “doll’s eyes“.

Interestingly, the berries are highly poisonous, and the entire plant is considered poisonous to humans. The berries contain cardiogenic toxins which can have an immediate sedative effect on human cardiac muscle tissue, and are the most poisonous part of the plant. Ingestion of the berries can lead to cardiac arrest and death! Strangely, the berries are harmless to birds, the plant’s primary seed dispersers.

Over the millennia, people have learned through trial and error which plants are good to eat and which are best to avoid. In our modern, urban world, much of that cultural knowledge has been forgotten.

Read more about plants that can kill you here.

The Circle of Leaf

April 19, 2010

In the Lion King the ‘Circle of Life‘ was the simple fact that lions ate antelope, but when the lions died the nutrients in their bodies were absorbed into the earth and eventually got into the grass, which was then eaten by other antelope, which were then eaten by another lion. It describes how energy moves through an ecosystem.

That’s the ‘Circle of Life’, this is the ‘Circle of Leaf‘:

Electrocuted mushrooms grow better

April 13, 2010

Lightning is an atmospheric discharge of electricity accompanied by thunder … and it helps grow mushrooms – seriously!

For generations, Japanese farmers have welcomed storms over their fields based on the belief that lightning strikes provoke plentiful harvests of mushrooms.

As part of a four-year study, scientists in northern Japan have been bombarding a variety of mushrooms in lab-based garden plots with artificially induced lightning to see if electricity actually makes the fungi multiply.

The latest results show that lightning-strength jolts of electricity can more than double the yield of certain mushroom species compared with conventional cultivation methods. Read more here.

WOW !!!


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