The plant keepers

Singapore Botanic Gardens was made a Unesco World Heritage Site last week, becoming just one of three gardens in the world, and the only one in Asia, to earn that honour. The Straits Times speaks to the passionate men and women helming plant research there.

Displayed in the Botanic Gardens' herbarium is a sprig of jasmine that has been preserved for more than 200 years.

Collected by missionaries in India in the year 1790, the plant was brought to Singapore and donated to the Gardens around 1879. While the dried specimen might not be much to look at, it is one reason Singapore has been feted as a leading centre of tropical plant research.

After the Gardens was founded in 1859, its herbarium was set up in 1875 to collect, document and preserve plants in the region.

It has amassed a vast collection of about 750,000 dried plant specimens and 15,000 plant samples preserved in alcohol, making it a crucial stop for botanists seeking to understand South-east Asia's flora.

Dr David Middleton, 51, the herbarium's keeper, said of its roots: "When it was founded, it was the main herbarium for Malaya."

He added: "Even after Singa- pore's independence from Malaysia in 1965, all of the collections remained here in Singapore."

In the past two years, seven new plants have been found in Singapore and named in scientific papers. These discoveries came after researchers compared their finds in the field to specimens in the herbarium's archives.

Its specimens are as diverse as they are extensive: Aside from the 225-year-old jasmine sprig, one section contains a century's collection of gingers from Penang, Perak and Pahang dating from the 1890s to the 1990s.

There are also specimens from the Cratoxylum glaucum Korth, a small tree first found in Bangka, an island east of Sumatra, Indonesia, in 1802, and from the Nepenthes klossii, a tropical pitcher plant first found in Papua, Indonesia, in 1912.

Some of the herbarium's plants once grew in Singapore but are now extinct here, such as the Thrixspermum psiloglottis (Ridl.) Schltr, an orchid with pale yellow flowers first found in Malaysia.

Every two weeks, a small team from the herbarium ventures into Singapore's green spaces, such as the Central Catchment Nature Reserve, to collect new specimens and learn more about the plants.

The researchers also survey sites in other parts of the South-east Asian region such as Brunei, Vietnam, Laos and Malaysia .

Dr Middleton, who is also the Gardens' deputy director and is in charge of research and conservation, said the field trips allow experienced staff to mentor their junior colleagues, so that skills are passed from one generation of botanists to the next. "There are more than 2,000 native species in Singapore, and the easiest way to identify them is when they are in flower or fruit, but that doesn't happen most of the time," he said.

"It's a great skill to be able to identify a plant, and the longer you do it, the better you get."

The regular surveys also enable the researchers to monitor changes in the landscape, sound the alarm about disappearing plants and inform conservation decisions - work that has become easier due to modern technology.

Ms Bazilah Ibrahim, 27, who helps manage the herbarium's collection, explained: "Some of the early collectors wrote very vague labels for their specimens, partly because they didn't have the equipment that we have now.

"The label might say Changi Road, for example, but we wouldn't know exactly where in Changi Road the specimen was collected.

"Now, we have GPS (global positioning system) and can pinpoint the co-ordinates."

Other labels have become obsolete, she added. "We've come across labels that say Chan Chu Kang. You can't find that on a map now, and you might assume that it was misspelt and actually means Choa Chu Kang. But there used to be a Chan Chu Kang. It just doesn't exist any more."

Dr Middleton said botanists now strive to document details that are lost when specimens are collected and dried for preservation, such as flowers' colours and fragrance, trees' height and girth, and whether the plants have sap.

The information helps researchers make better decisions about plants they encounter in the field - if a tree's parts resemble specimens in the herbarium, but it is much taller than indicated in the specimens' label, for instance, it could be a different species.

In 2013, the herbarium began digitally scanning its approximately 8,000 plant "type specimens" - the very first of each species or sub-species of plant to be described and named. This was its contribution to the Global Plant Initiative, an international effort started in 2003 to create a comprehensive online record of plant type specimens.

Singapore's plants are among the most well-known and collected in the world - with about 5,720 plant specimens collected for every 100 sq km, the highest collection density reported for any tropical country. But botanists believe their depths have not been plumbed.

National University of Singapore research assistant Lahiru Wijedasa, 32, a former senior arborist with the Botanic Gardens, said the herbarium's own collection may hold surprises, since many foreign researchers who had toiled in Singapore's forests left the country after the end of World War II.

While plant specimens were still collected and deposited in the herbarium, there were few people left to identify them. In the past few years, the number of researchers has grown again. Recently, specimens of two plant species in the herbarium, some of which date back to 1890, were discovered to be mislabelled, and the species were actually new to science.

Dr Middleton noted that about 100 to 150 years ago, the biodiversity of the whole of South-east Asia was poorly known. "There have been so many discoveries made since then, but there is still so much left to do. Even in Singapore, we still have new things to find."

It takes years for a newly created orchid hybrid to flower

Singapore Botanic Gardens was made a Unesco World Heritage Site last week, becoming just one of three gardens in the world, and the only one in Asia, to earn that honour. The Straits Times speaks to the passionate men and women helming plant research there.

One day after former Prime Minister Lee Kuan Yew died in March, the National Parks Board announced that it had named a hybrid orchid in his honour.

But the new orchid, which has bright golden flowers with a green tinge, was years in the making.

Mr Simon Tan, 31, assistant director of the Botanic Gardens' National Orchid Garden, told The Straits Times that the Aranda Lee Kuan Yew orchid had taken about four years from the day its parents were crossed to its first flowering.

Mr Lee's hybrid is a cross between a native orchid, the Arachnis hookeriana, and a hybrid orchid from Hawaii. It shares a few species in its lineage with the Vanda Kwa Geok Choo, the orchid named after Mr Lee's wife, who died in 2010.

Mr Tan said that, in general, it takes two to six years from the day a hybrid orchid's parents are crossed to its first flowering.

The gardens has more than 1,000 species of orchids and about 2,000 hybrids, housed mainly in the National Orchid Garden, making it the largest display in Asia.

Since 1956, Singapore has also named 210 orchids after important guests and dignitaries, such as Queen Elizabeth II, Margaret Thatcher and Nelson Mandela.

The first such "VIP orchid" was the Aranthera Anne Black, named after the wife of a former governor of Singapore.

Mr Tan said the National Orchid Garden's breeders aim to create about 20 quality hybrid orchids every year. The hybrid orchid to be named after each VIP is usually chosen from those that are flowering during his visit. "We can sort of project what we want to achieve, such as certain colours, size and form of the flowers and the size of the plant, but that depends on a bit of luck," he said.

Mr David Lim, 70, the orchid garden's nursery manager, said that, usually, the hybrid's mother imparts the size and shape of its flowers, while the father is responsible for characteristics like the flowers' colours. "But there are also certain genes that are very dominant, such as genes that give you red flowers. Whatever you cross with those genes, you will most likely get red flowers," he said.

Hidden or recessive genes in the parents may also throw a spanner in the works. Orchids with recessive albinism genes, for example, may produce unexpected white flowers. But even without hidden surprises, the process of achieving the wanted colours is not as straightforward as mixing paint colours. "You don't get green through yellow and blue. It's not that easy," said Mr Tan.

He added that with 25,000 to 30,000 known species of orchids, experience counts for a lot in creating hybrids. "There are scientific principles behind the process, but it's still very intuitive and complex," he said.


This article was first published on July 10, 2015.
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