Tuesday, 23 April 2013

Tourist’s novel orchid find

Scientists have confirmed that an orchid discovered by a tourist in South China is a new species.

The dazzling flower is entirely yellow and the plant has no leaves for photosynthesis and carries the biggest seeds of all known orchids.

Named as Danxiaorchis sinchiana, it was found in the remote mountains of Shaoguan, Guangdong province, by .

In May 2010, tourist Zhu Jiaqiang and some friends were hiking in Danxia when Zhu came upon half a dozen beautiful orchids in a grassless area. He took photos and posted on the internet, drawing the attention of botanists.

Scientists from various specialist centres went to the mountains with Zhu and have now concluded that it is indeed a new species. A news conference has just announced the discovery.

According to a press report, Liu Zhongjian, a senior expert with the Asia branch of the International Union for Conservation of Nature's orchid group, said: "The discovery of Danxiaorchis sinchiana has enriched the diversity and gene bank of the orchid species, and the special structure of the seed provides a new research interest for orchid evolution."

Other plant species have also been reported in the area, but human activities have limited the range of orchid species. Liu has called for authorities to build a protection zone for the new species and start gene research for a possible reproduction study.

So far, scientists have found 21 individual Danxiaorchis sinchiana, with the total number estimated at less than 100.

Saturday, 20 April 2013

Earthworm fear for forest orchids

Worms are great for your garden, but a recent study shows that non-native species may be wreaking havoc on orchids in forests along the east coast.

A group of scientists from the Smithsonian Environmental Research Center (SERC) and Johns Hopkins University’s Department of Earth and Planetary Sciences recently published a study that shows the damage non-native earthworms, which creep their way into forests thanks to human activities such as fishing and gardening, may cause to one of the world’s favourite flowers, the orchid.

Of more than 20,000 orchid species, the study focused on Goodyera pubescens, a tall, erect plant with white flowers common in America’s east coast forests, including those around the SERC campus in Edgewater, Maryland. The problem with earthworms, the scientists found, is that they reduce Goodyera pubescens’ numbers by ingesting their seeds, which are the size of dust specks and fall into the soil surrounding orchids when the plants flowers. As earthworms eat through the soil, they swallow the microscopic seeds, preventing germination in two ways: either the ingestion process kills the seeds before they make it out the earthworm’s other end, or the seeds survive ingestion but are reintroduced into the soil too deeply to access upper-level fungi nutrients required for growth.

The team determined that almost 80 per cent of the seeds ingested in a six-week period could no longer grow, and almost a third were buried too deeply to flourish. By a conservative estimate, the study concludes, older forests – 120 to 150 years old – around SERC would lose 49 per cent of Goodyera orchid seeds to earthworm ingestion in a year, and younger forests – 50 to 70 years old, where non-native earthworms flourish – would lose 68 per cent.

These numbers do not suggest that earthworms are inherently bad for orchids. On the contrary, native earthworms keep the plants’ ecosystems in balance, and allow plenty of room for growth. What the numbers do show is that the unchecked introduction and proliferation of new earthworm species in forests has a dramatic effect that defies the conventional wisdom that earthworms always are great for soil health.

As part of a forest ecosystem, orchids actually are relatively insignificant, however, earthworms also might disrupt the distribution and diversity of the fungi on which the orchid seeds feed, which would have a much more fundamental effect on the forest, because many plants depend on them. 

By Pamela Kelt

Wednesday, 17 April 2013

Naughty orchidmaniac

Just the other day, a fellow orchidmaniac contacted me about this extraordinary botanical document they’ve just re-evaluted in Denmark.

The State Museum was preparing for its new exhibition, 'Flowers and world views' which runs until 20 October. The idea is to present a spectacular and lush extravaganza of flower paintings spanning two centuries.

The exhibition offers a sensuous walk through the rich variety of the world of flowers, but it also digs deeper to show that a flower is not simply a flower. The artists’ representations of flowers, fruit, and plants are affected by history and the prevalent world view. ‘A picture of a flower is a picture of its own time.’

Five other museums in Copenhagen are all running flower exhibitions.

A key element in the state museum exhibition is the 'Gottorfer Codex’. Since 1835, the giant flower study by artist Hans Simon Holzbecker, of Hamburg. It has lain dormant in the basement of the National Gallery of Art in a special box behind a reinforced door among the most important works of art. Take a look for yourself here.

Researchers took a closer look and were shocked when they magnified certain plates in the hand-painted botanical (or maybe rather horticultural) work commissioned by Duke Friedrich III of Schleswig-Holstein-Gottorf (1597-1659) that now resides in Copenhagen.

Among the petals of the so-called ‘Orchis Italica’, there are numbers of tiny, naked men worked into the illustration. (Pictured right is less controversial illustration from the 19th century.)

In the Middle Ages, orchids were equated with aphrodisiacs – partly because of their resemblance to testes (orchis in Greek). There was a belief that medicine should resemble the cure. Holzbecker, it seemed, added tiny cartoon-like drawings of men, obviously responding to treatment, as part of the flora.

An article in the Danish press discusses the apparent indecency of the homunculi. Was Holzbecker, although a brilliant and accurate artist, still influenced by earlier belief, that plants would show their medicinal powers (if any) in their appearance? Or is it simply because the illustratror was becoming bored of the detailed task?

Here's the link, but it’s in Danish.

If you want a moment of true orchidelirous bonkerosity, run it through a well-known web translator.

By Pamela Kelt

Illustrations: Tulipa gesneriana from the Gottorfer Codex
Orchis italica (as syn. Orchis longicornis), 1818, "Curtis's botanical magazine" vol.45 pl. 1944

Monday, 15 April 2013

Orchids and fungi

Some plants produce seeds that are so small that they do not have sufficient reserves to germinate underground unaided.

In fact, around 80 genera representing 10 per cent of plant species, most of which are orchids, are in this category. So instead, these plants parasitise soil fungi which supply the developing seedling with carbon and much of their mineral nutrient requirements (mycoheterotrophy).

Mycoheterotrophy is essential for establishment of gametophytes and seedlings of many “lower” and “higher” land plants. Although a widespread and common strategy for recruitment employed by many of the worlds’ most rare and threatened plant species, including most orchids, virtually nothing is known about the mechanisms required to parasitise fungi and how this strategy has evolved.

A PhD studentship has been advertised at the University of Sheffield, under supervisor Dr Duncan Cameron, with the aim of resolving the identity of the main metabolites passing from fungus-to-plant in mycoheterotrophy, as well as identify whether the major groups of mycoheterotrophic orchids exploit different metabolic pathways.

Pictured: Pacific coralroot is an example of a mycotrophic plant that obtains its organic carbon from a host green plant by tapping into an intermediary mycorrhizal fungus attached to the roots of the host plant

Friday, 12 April 2013

Singapore seeking heritage status

Singapore is pushing for its 154-year-old Botanic Gardens to be declared a UNESCO world heritage site.

The lush 182-acre park on the edge of downtown Singapore could join prestigious members such the Royal Botanic Gardens in London.

Founded in 1859 by the Agri-Horticultural Society while the island was under British colonial rule, the gardens became known for pioneering rubber tapping and orchid-breeding techniques. 

They are a key attraction for Singaporeans and tourists with up to four million visitors a year in a city-state of 5.3 million people.

The gardens boast more than 30,000 plant and tree species, according to the Singapore National Commission for UNESCO, as well as a swan lake and a concert amphitheatre.

It is particularly known for its VIP and Celebrity Orchids area, where varieties are cultivated and named after famous people, from Princess Diana to Nelson Mandela, reports the Daily Telegraph.

Pictured: Paravanda Nelson Mandela in the National Orchid Garden, Singapore Botanic Gardens.

By Pamela Kelt