Sunday, 28 February 2010

March - Summer's Last Gasp?

My seasonal correspondent (in that he emails me seasonally, about seasons), Rick Kemp, asked me a few weeks ago whether I thought 1 March was the first day of Autumn.

Rick has thought longer about seasons that me and I'm aways eager to hear his views. As always, he was diplomatic. He knows I favour seasons based on climatic and environmental changes, while he, on balance, prefers what he calls solar seasons (seasons based on distance of the earth from the sun).

I should stress that Rick's solar seasons are not your run-of-the-mill four seasons. He would prefer a series of transition periods between each of our classic seasons, resulting in maybe eight recognisable units. But that's for another day.

The last email, in late February, was all about when autumn starts in Sydney. Rick first presented the case for tradition, at least in Australia, where autumn starts on 1 March.

Our calendars say it's autumn so it must be. April and May are the autumn months. More interestingly, Rick observes some of the 'indicator plants' of autumn are doing there thing. Sasanqua camellias are starting to flower, Freesia leaves are emerging from the soil and autumn crocus are blooming. I noticed myself that Plane Trees leaves are browning at the edges, getting ready for their autumn drop.

Alternatively, using Rick's 'solar seasons', autumn (or the transition season leading to autumn) has already started with the rapid shortening of photoperiod, particularly in the afternoon. Rick feels there is less need of a shoulder season between summer and autumn than there is between winter and spring.

The third alternative, and my preference at the moment, is that summer continues until the end of March and we have a short autumn in Sydney, from April to May. As Rick noted, it still feels like summer. In many Northern Hemisphere countries the Equinox (around 21 March) is used for the start of autumn so in that system there are plenty more weeks of summer left. In Australia, we now finish Daylight Savings on the first Sunday in April so that's a very neat place to finish summer.

I will admit that a week or so ago the mornings began to get a little crisper and the heavy humidity of high summer seemed to have passed, but I'm wary of these temporary weather fluctuations. The heavy rains in early February created a distinctive climatic feel for us in Sydney this year, and who knows what is around the corner in March. Also, are we experiencing a kind of 'shoulder' period similar to early December?

Maybe it doesn't matter, but at the very least I'm observing plants and animals more closely, and I'm judging seasonal changes more by the environment and climate than the cadences of a calendar.

Image: The first sasanqua camellia flowers for 2010 in my own garden. For more on seasons see previous postings.

Friday, 26 February 2010

The Busy Bursaria*

Senior Ecologist Doug Benson and co-workers at the Botanic Gardens have been studying some remnant pieces of woodland at Mount Annan Botanic Garden for the last 21 years or so (from when the Garden was opened).

You can read all about it on the web – find our botanic gardens site and then click through Science, Research and then Ecology of Cumberland Plain Woodland.

As Doug says on the website, Cumberland Plain Woodland once covered about 125 000 hectares on the clay soils of western Sydney, from Kurrajong across to Picton. Clearing for farming and urban development have reduced it to a few small remnants today, many of which are under threat. The whole community is now listed as an Endangered Ecological Community.

This woodland isn’t the most beautiful pieces of vegetation to the untrained eye. It’s often dry and sparse, with few big showy flowers. If look closely though, there are lots of fascinating plant and animal stories.

One of the common species in this community is the Sweet Bursaria or Blackthorn, Bursaria spinosa. It’s a stiff, prickly shrub which can live up to 60 years. The flowers are small and white, and the dry fruits shaped like a purse.

In February, Sweet Bursaria is in full flower and perfume, and it’s very sweet! (Bursaria is in the same plant family as the native Pittosporum, another sweet-smelling plant.)

When in flower, Sweet Bursaria attracts lots of insects, including butterflies, moths, bees and beetles. A native bee is the usual pollinator and the Pittosporum Beetle, named from its association with that close relative, is a frequent visitor at Annan – this bug has a distinctively bright red head and underbelly.

I remember Sweet Bursaria well from when I lived in Victoria. At places like Castlemaine (where my parents still live), the rare Eltham Copper Butterfly depends on Sweet Bursaria for its survival. Eggs are laid on the shoots and stems of the Bursaria, and the larvae eat some of the leaves while being attended by local ants (who feed off secretions of sugar and other bits and pieces from the larvae, and in return probably destroy nasty fungi and bacteria). The adult butterflies then feed on the nectar produced in the Bursaria flowers.

The nectar, as well as the insects, also attracts plenty of birds. And small birds, like the Blue Wren, can nest safely in the prickly branches.

For humans, the leaves contain an oil called aesculin. Aesculin absorbs ultraviolet light and the leaves were rubbed onto skin by early settlers to help prevent sunburn.

It’s a tough plant, and after fire the shrub resprouts from a large tuberous root. Doug Benson’s team has confirmed, among other things, that seedlings are established mostly during extended rain periods and that rabbits enjoy eating them.

Image: Pittosporum Beetle on Sweet Bursaria (photo Lotte von Richter). *This Passion for Plants posting will also appear on the ABC Sydney website (possibly under 'gardening'), and is the gist of my 702AM radio interview with Simon Marnie on Saturday morning, between 9-10 am.

Wednesday, 24 February 2010

Four Seasons Back Together Again!

Tomorrow (Thursday, 25 February) we unveil four 120 year-old statues representing the seasons of the year. After at least 50 years apart, and some of them losing vital body parts, our Four Seasons are reunited in every sense.

The Four Seasons are some of the oldest surviving statues in the Royal Botanic Gardens, shipped from Italy in 1883. They were originally situated together on the Garden Palace Steps but were later separated and distributed around the Gardens. The two females – spring and summer – lost their heads in the 1970s.

Of course they represent the four European seasons. In Australia we have at least five seasons, so an extra spring statue has been moved to the Spring Walk to celebrate the early Australian flowering season I call sprinter (August & September).

Our stone statues have to endure all seasons of the year, plus occasional vandalism, so every now and then they’ll need some tender love and care. But hopefully we won't have out seasons out of action for as long next time.

The Four Seasons were part of a shipment of statues from the studio of the (Australian-born sculptor living in Rome) Charles Francis Summers, to replace statues lost during the burning of the Garden Palace. Charles F was the son of well-known Australian sculptor Charles Summers.

These statures are part of the rich cultural history of the Gardens going back to 1816. In this case they are part of the Victorian element of the Gardens.

Some of our Victorian statues were removed during 1910s for moral reasons, others during 1970s for reasons of artistic taste. Of those that survived, the two females - spring and summer - lost their heads in the 1970s or thereabouts…

Sculptor Jacek Luszczyk has now created a new head for Summer and repaired Spring’s noggin. He's also repaired the sickle and iris for Summer, and a hand for Spring. All four seasons have been cleaned up and repaired under the guidance of International Conservation Services, led by Julian Bickersteth.

A fill-in smaller ‘Spring’, possibly from 1879, has been moved to the Spring Walk, celebrating my proposed fifth season, 'sprinter', beginning on 1 August. Little Spring lost her arm during the Olympics but we hope to have this repaired soon.

Image: This armless 'little' spring has been moved to the Spring Walk. Four freshly repaired and cleaned statures now bookend the Garden Palace Steps.

Sunday, 21 February 2010

Underwater Mushrooms a Gas

Just when you think you've seen everything, the web reveals a picture of a mushroom growing under water, producing bubbles of carbon dioxide. This picture is from the front cover of the latest issue of Mycologia (a scientific journal on fungi), and copied here from a lovely blog site called 'The Artful Amoeba - a blog about the weird wonderfulness of life on earth'.

The moss is producing bubbles of oxygen as it uses sun energy to turn carbon dioxide and water into sugars, but the fungus is doing what fungi do, and breaking down food storage products to get energy - carbon dioxide is a biproduct.

Its not that we didn't know fungi grew underwater. In 1984 I edited a field guide with the catch title of Aquatic cryptogams of Australia : a guide to the larger fungi, lichens, macroalgae, liverworts and mosses of Australian inland waters (published by Australian Society for Limnology).

In there are plenty of weird and wacky fungi that grow under water. However none of them are gilled mushrooms. The mushroom is one of the fruiting structures found in a particular group of fungi called the Basidiomycota (or basidiomycetes). Within this group, the gilled mushrooms are commonly called the agarics.

Despite the fishy adjective, we expect to find gilled fungi in paddocks, forests and supermarkets, not underwater. So the record of a genus called Psathyrella fruiting regularly in the Rogue River in Oregon, USA, was worthy of some fanfare.

There was, and perhaps still is, some scepticism around this discovery. The authors of the paper watched this fungus over a few months to make sure it didn't just produce one mushroom that happened to be flooded by water. Over 11 weeks the fungus produced its fruiting bodies underwater, always fully submerged. It also has a distinctive shape and form, as well as characteristic DNA sequences, so it's a new species of Psathyrella, presumably adapted for this odd habitat.

The fungus grows along half a kilometre of the river, above and below a waterfall, so the authors conclude it is not a single clone or colony.

The next test for the researchers is to try and grow the fungus in the laboratory, both underwater as well as above.

As always when you find something in a river, people ask how does it get upstream. I get this question about the freshwater red algae I study, which typically grow on rocks in small mountains streams.

In the case of the fungus its been suggested aquatic invertebrates and other animals carry it around. Perhaps its dispersal relies entirely upon animals. With algae, sometimes aquatic birds are suggested. Alternatively, for groups with a long evoluntionary history they may evolve in a swamp or waterbody that ends up moving and flowing in various locations. As long as it remains firmly anchored, the world moves around it...

Part of the surprise of this discovery was that previously no one had looked underwater for mushrooms. It had been assumed they wouldn't be there - floppy, gilled fruiting bodies didn't seem to be well adapted for this habitat. Fungal foragers will now have to don their togs, bathers, swimmers or cosis (depending on what part of the world, or Australia, they live in...)

If you want more background to the story see the blog I mentioned at the start, the beautifully named Mycorant or go to the source of the story at Mycologia. (And thanks again Jim Croft for the link.)

Friday, 19 February 2010

First Graders in the First Farm

Yesterday I was out recording my regular interviews with Simon Marnie from the ABC Sydney Radio (702AM) Weekend Show. I'm sure I'm not giving away any trade secrets by saying we do a few at a time.

I try to find a plant or place relevant to each story. For example we visited the Cadi Jam Ora garden to find a Magenta Lilly Pilly (or Daguba), eaten raw by the Cadigal and made into jams by more recent inhabitants of this land.

For a chat about wild carrots, and their colour - purple or red rather than orange (more about this in my Passion for Plants posting in a few weeks) - the First Farm was the obvious location. Although we don't have carrots at the moment, there are asparagus, corn, coffee, bananas...etc.

Unexpectedly, and pleasantly, the garden was full of young children and their parents. There were family groups picking and tasting asparagus. Imagine that, someone under 5 years old tasting a new vegetable! Another child had a paper bag with as many corn cobs as they were years old (4).

Normally we don't eat or pick our garden. Robert Dessaix in his intriguing Night Letters (1999) laments that "botanical gardens aren’t really gardens at all, of any kind. They somehow contrive to be neither orchards nor flower gardens, nor kitchen gardens, nor physick gardens, nor even parks. They’re static, nothing’s happening – no flowers are being picked, no fruit eaten, no medicines boiled up, there’s no one picnicking or admiring the view. It’s a museum, not a garden. Paradise was never a museum."

Dessaix was sipping a cappucino outside the botanic gardens in Padua, the oldest botanic garden in the world (dating back to 1545 - the botanic garden in Pisa was established a few years earlier but has since moved...). In the end he decided not to visit the botanic garden, deciding that if you've seen one you've seen them all.

Tough words, and not quite true of course. For the observant there is something new happening every day, whether the plants, events or just visitors living out their lives. There is certainly picnicking in the Royal Botanic Gardens in Sydney, and sunbaking, and a whole lot of things I can't record here.

Still, it's good to be tested on these things and to be provoked. In the First Farm garden yesterday, there were people picking and eating plants. It is a special place and special activity, but it was great to see.

If you want to pick a plant in one of our botanic gardens, and you are under 5, come along to Dandy Lions, 'gardening, activities and storytelling for 0-5 year olds'. As our website says, 'Bring your wild thing and come out to play!'

Dandy Lions is held every Thursday (except 8 and 16 April), from 10 am - 12 noon, weather permitting (not when raining, high winds or temperatures above 35 degrees C...). It costs $11 per family, with a maximum of two children, and this even include a coffee for one at the Gardens Cafe! For more information contact Community Education, ph: 9231 8134.

So Mr Dessaix, we have picnics, plants being picked and eaten, and even a decent cappuccino. This is a botanic garden worth a visit...

Image: some very cute kids and a lion, from the Dandy Lions webpage.

Saturday, 13 February 2010

Art Inspried by the Single Most Important Event in the History of Life on Earth

Another week, another art opening. Yesterday it was a great pleasure to MC the opening of an exhibition by our 2009 Artist in Residence, Jenny Pollak.

In the Beginning (Red Box Gallery until 26 March 2010, weekdays) and 21%O2 (Palm House until 22 February 2010, everyday) are now open for viewing. Jenny will talk about her art and lead a tour of the exhibitoins at 10 am on 17 February - see website for booking information.

Jenny Pollack is the Botanic Garden Trust's fifth Artist in Residence. The list is very impressive, and diverse: Chris Gentle – 2005, Gaye Chapman – 2006, Ana Wojak – 2007, Emma Robertson – 2008, Jenny Pollak - 2009.

As I said in my opening remarks, each artist has responded to the botanic gardens quite differently and in a variety of media. Each has produced beautiful and inspiring art.

Jenny Pollak has parents who are scientists which probably explains why she is an artist...but with a scientific slant. She began as an artist working in etching, printmaking and lithography in London in 1976, then became more interested in photography and sculpture.

This is her second Artist in Residence position. Her first was in the Electron Microscope unit at the University of Sydney in 2005/2006 – her artwork then was inspired by photographing microscopic organisms.

Jenny also a love of South American music and is inspired by the beauty of the bush and the sea at her home. Here in the Botanic Gardens, it seems she was inspired by algae, and who can blame her!

Evolution was always going to be a strong them in the year of Charles Darwin’s bicentenary. (In fact the opening yesterday was on what would have been his 201st birthday.) 2010 is the Year of Biodiversity – celebrating species, their genes and their ecosystems - so very timely for the exhibitions.

Jenny said she drew inspiration from a book on Algae (by Linda Graham and Lee Wilcox), and in particular the quote “The rise to dominance of cyanobacteria — the earliest known oxygenic photosynthesisers — has been described as the single most important event in the history of life on earth”. Jenny says "It contained all the elements of a great drama".

As I noted last night, the Earth is about 4.5 billion years old earth. For the first billion years very little happened in terms of life but then 3.8 billion years ago the cyanobacteria (blue-green algae) dominated the earth and started to produce oxygen.

Just a few hundred thousand years ago humans evolved. In between, its really all about a few other living things.

In the Red Box Gallery you'll see Jenny respond to the ancient lineage that connects humans indelibly to all living things. I’ve watched the exhibition evolve over the last few weeks, fascinated by each new piece. The result is fascinating and fun.

Jenny won an Arts Council of Australia grant for the installation in Palm House and it's a different experience again. Jenny describes it as a “visual metaphor for the alchemical process that gave rise to the first oxygen-dependent life on earth”. You'll need to hurry along in the next week or so to enjoy this one (before the possums do, but that's another story, and one that Jenny told at the opening).

* * *

Guest Speaker last night was Stephen Dernocoure, a fellow artist. Stephen started as an illustrator for magazines but has been exhibiting work for over 30 years. Most importantly, he is highly regarded teacher in a range of settings. Currently he works a lot in palliative and psychiatric medicine, drawing on science, philosophy and culture. Healing and helping people.

He spoke about how important the viewer of the art was to the art itself and how well Jenny had placed us 'behind the art'. He spoke poetically and movingly about how important art was to lives. When we met beforehand he spoke equally passionately about the role of plants and gardens in healing.

Jenny thanked everyone at the Botanic Gardens Trust and other helpers. I should record here my thanks to the Artist in Residence team (Lesley Elkan, Dale Dixon, Emma Robertson and Relle Mott), Alan Millar for providing seaweed (algae), Miguel Garcia and Judy Blood from the library, Dawson Ougham and other horticulturalists, and Lesley Elkin and Sophie Daniel for help with the hanging and display of the art. Staff in the Botanical Information Service and Events also assisted in bringing these two exhibitions to life.

Clarence Slockee, as always, brought us to life with his acknowledgement of country, paying particular tribute to the Gadigal, the traditional custodians of the land. Although not as elaborate as usual (it had been a hot tiring day out in the Gardens!) he returned later to lead the procession of people from the Red Box Gallery to the Palm House, and yet more summer rain in Sydney.

Image: One of Jenny Pollack's artworks featuring algae, on display in the Red Box Gallery - picture from the Botanic Gardens Trust website

Friday, 12 February 2010

Lord Howe Wonders*

[I've covered most of this topic
previously but as usual, here are the notes from my chat with Simon Marnie that didn't quite run due to technical problems... *'Passion for Plants' postings will also appear on the ABC Sydney website (possibly under 'gardening'), and are generally the gist of my 702AM radio interview on Saturday morning, between 9-10 am.]

I visited Lord Howe Island for the first time last year and saw just a few of the plants that are found only on this 7 million year old, 56 square km, volcanic island. There are 243 native species and varieties, with just over 100 found no where else in the world.

The star attractions are the giant figs and the palms. The four palm species grow naturally here and no where else – i.e. they are endemic to the island – although you’ll find one of them in gardens around the world.

There are three genera, all of them endemic to the island: two have only one species, and the best known, Howea, two. I saw them all on a walk to the top of Mount Gower.Although both Howea species are sometimes called Kentia Palm in the horticultural trade, it’s Howea forsteriana, known on the island as the Thatch Palm, that is more widely grown under this name.

The second species, Howea belmoreana, is called Curly Palm on the island.Three botanists from London – Vincent Savolainen and Matthieu Boulestiex from Imperial College London and Bill Baker form Royal Botanic Gardens in Kew (England) – have been studying these palms in great detail over the last few years.The Thatch (or Kentia) Palm grows from sea level to around 300 m, the Curly Palm starts a little higher (at 50 m) and grows up to 400m. The fact that the ranges of these two closely related species overlap has intrigued botanists for some time.

The London trio found the two palms had diverged from a common ancestor less than one million years ago, on Lord Howe Island. Speciation – the process of a new species being formed – has been what we call ‘sympatric’. This means, as I said above, the two species grow in the same place.

The Thatch Palm flowers on average six weeks before the Curly Palm, which may have been enough to allow them to go their separate ways. However there is enough overlap to allow cross-fertilisation. Hybrids exist on the island and you can see one in the Palm Grove of the Royal Botanic Gardens (if it has survived our flying-fox friends).

Our London colleagues continue to discover curious things about our palms. Both are wind-pollinated, even though most palms are pollinated by insects. And the Thatch Palm includes genetic variants across the island: for example, there is a distinct cluster near Ned’s Beach. These populations may well be in the early stages of becoming new species themselves.

The value of the palms to the island’s ecosystem goes without question, but one local curtly noted that ‘Kentia Palm is good for producing seed to grow more palms, and that’s about it!

I can’t finish without mentioning the figs. There is a form of the Moreton Bay Fig found only on Lord Howe Island called Ficus macrophylla f. collumnaris, or locally, the Banyan. Mature trees have 10 or more trunks, each one starting as an aerial root dangling down from a huge spreading branch. These are impressive trees and the forest just grows up through the largest of them which cover about 1 hectare.

Image: Aerial roots dangling from the Lord Howe Island form of Moreton Bay Fig, on Lord Howe Island

Thursday, 11 February 2010

Fungal Warming

Plenty of plants generate heat to attract pollinators, including the giant Titan Arum we have on flower every now and then at the Royal Botanic Gardens in Sydney, and many cycads.

These plants reckon (in an evolutionary sense of reckoning) that it’s worth putting energy into heating if they can increase their changes of successful cross-pollination. So if the Titan Arum (Amorphophallus titatum) produces heat along with its rank smell of dead possum, it will attract plenty of flies so that its flowers are fertilised and produce seed.

One plant has found a way to warm its flowers but not invest the energy, at least not directly. One of the hellebores, a genus of plants popular in gardens around Australia but native to Europe, has the attractive common name of Stinking Hellebore, because…it stinks. Its botanical name, Helleborus foetidus, also alludes to this unsavoury character.

Rather than produce the stink and heat itself, it gets help from a fungus. Most of us know by experience that fungi – whether on food, fashion or feet – can stink. They range from faint musty odours to quite rank. But they can also generate heat.

In this particular case, a yeast (the same fungus that gives us bread, beer and vegemite) is deposited on the Stinking Hellebore flowers by a bumblebee. The hypothesis was that these yeast cells generated the heat, and I presume the smell (this study focussed on heat only).

Scientists working at the DoƱana Biological Station in Seville, Spain, injected clean specimens of the Stinking Hellebore with this yeast and found that they were 2-7 degrees C warmer. The results of this study have just been published in the Proceedings of the Royal Society.

The yeast generates heat as it ‘digests’ the floral nectar. So although the plant doesn’t have to produce its own warmth, it does sacrifice some nectar to the fungus. Everything has a cost but this yet another example of a nice symbiotic relationship in nature.

Image: Extracting some of the smelling, warm outputs from the Titan Arum. (Thanks to Jim Croft for story idea.)

Sunday, 7 February 2010

Art Inspired by Ancient Plants

I had a surprise invitation a week or so ago, to open an exhibition of paintings in the Cessnock Regional Art Gallery. Apologising for such late notice (the original opening guest had had to pull out) Hadyn Wilson wondered if I might be available this weekend for a trip to Cessnock.

The weekend was pretty free and having not yet visited the Hunter Valley after 11 years in Sydney – very poor I know - I was tempted. When I looked at the artwork on the web, I was hooked.

If you are visiting the Hunter Valley over the next month (until 8 March) I’d definitely suggest a stop over at Cessnock to see this small, but wonderful, exhibition of botanically inspired artwork. It’s called ‘Stories from the Archive: A Palaeobotanical Narrative’ and represents 10 years work. Tomorrow, I understand, it will be examined as part of his PhD study at the University of Newcastle.

So I said yes and I'm very glad I did. Not only is the art amazing and Hadyn Wilson a charming person, I was able to enjoy the produce and hospitality of the Hunter Region (and thanks to Virginia Mitchell for all her support and advice). Below is a bit of summary of what I said on Saturday evening (with the tense all over the place...)...

I started by noting that I was keen to open this exhibition for two reasons. Firstly the artwork is fascinating and fun. Works on internet looked great, better on a CD and now in reality…fascinating! Secondly, I think extinction is an intriguing and misunderstood concept. Death and extinction are a critical part of evolution. Along with reproduction and ‘fitness to survive’ is the necessary corollary of death and extinction.

But before I got onto extinction an all that, I gave a little background to Hadyn Wilson himself:
· Attended Art School in Sydney; Institute of Arts at ANU; Masters of Fine Arts, UNSW and now nearly completed a PhD at University of Newcastle.
· Taught at art schools and universities; study tour in New York and Prague
· Painting and exhibiting for the last 30 years
· Represented in more than 60 exhibitions, including more than 30 solos, and in private and public collections around the world.
· Many awards, including: Travelling Art Scholarship, Mosman Art Prize, Art of the Rocks 1st Prize.

And so to the exhibition and to extinction. I spoke about the Australian flora being under threat and the long evolution of plant life on Earth. I mentioned that the first plants to trap the sun’s energy and turn it into food – the basis of oxygen and life – evolved 3.8 billion years ago. They were the Cyanobacteria, or blue-green algae, featured in a couple of Hadyn’s works.

Flowering plants go back a mere 100-150 million years. We have clues about what the first flower looked like from 125 year-old fossils from China and a group of living plants around the world, including Amborella, a non-descript plant from New Caledonia. These plants carry in their DNA all the information we need to track their family tree and in theory the first flowering plant. Hadyn makes reference to Amborella and to the ‘first flower’.

I said humans are less than half a million years old, with the whole human clan branching off from chimpanzees only 5 or so million years ago. Of course Hadyn has them harvesting and living among ancient fossil plants, which is the great thing about art!

While there might be 1.5 million known species living on earth today (we humans are one), and another 1.5 million or up to 100 million yet to be discovered and described, most species that have lived on earth are extinct. That said, the loss of any species is a sad and dramatic event. Not something we should just allow to happen as a by-product of doing other perhaps less important things.

I went on to talk about it being important to remember that the species we live with today (the last few hundred thousand years) are the ones we evolved with as a species. Some of these species are ones we depend on now, or may need for the future. Scientists today also talk about the ‘resilience’ of a community and its ability to adapt to change. When it comes to what are called the ‘tipping points’ – when an ecosystem will change or be wiped out – having some duplication and resilience may be critical.

On top of these practical considerations for us, the species on earth today are also the ones we have got to know and love – part of our world family. Each is a unique outcome of evolution and won’t evolve again. It has its own beauty and interest.

For me these were the kinds of things we could contemplate as we looked at Hadyn’s artwork, mostly based on fossils from the Hunter Valley. I said fossils are what are left of a living and vibrant plant or animal from our past. Hadyn is incorporating into his paintings images of fossils – the equivalent perhaps of terracotta warriors from China or ancient (not modern) rock art uncovered in the Blue Mountains or Arnhem Land. Fragments of the past.

As with ancient artwork, we should look at fossils as a celebration of past glories as much as a loss of what might have been. From this art you remember that fossil plants were once living plants – growing, evolving, even...being harvested! Hadyn has filled in the gaps, with imagination, which is just what scientists do with fossil fragments – they create a story based on fragments of the past.

Hadyn says he was inspired by Mary White’s books (later becoming friends with Mary) and the ‘imaginative leap’ required to make this science understandable and relevant to everyone. Also perhaps the leap from fossil to a once living world that is now extinct…

Hadyn has created a landscape – an imagined and imaginative landscape – much as the scientist has done. He tells a different story to the scientist but an equally compelling one. I’m sure there is a book in all this – ‘A Traveller’s Observations’ perhaps?

There are stories in here about lost worlds, conservation, science… But more than this, these pictures magnify and refocus the wonder of the natural world. There is happiness and sadness in this world of fossils, and in theses stories, for all the reasons I mentioned before.

I ended by noting that we humans are part of the story, and definitely part of Hadyn’s artworks. Do take a look.

Images: The artist and me in front of one of his most striking pictures (A Laurasian Legacy), followed by 'The Sunny South and Cyanobacteria). Below are a selection of pictures from the Stories from the Archive series and finally the dark but evocative The Aspirations of Pollen.

Friday, 5 February 2010

Plant Poisoning Potential Pollinators?

It’s generally thought that almonds contain cyanide, albeit in small amounts so that unless you eat a whole lot of them you won’t die.

In fact wild ‘Bitter Almond’ kernels contain a chemical called amygdalin, which can be broken down by enzymes in our stomach to produce cyanide. It is particularly concentrated in unripe fruits.

For this reason you shouldn’t eat (wild) Bitter Almonds or use amygdalin for medicinal purposes (amygdalin has been promoted in the past as a cancer treatment, but clinical trials have shown it to be ineffective in treating or controlling cancer).

The almonds we buy in shops are apparently free (or very close to it) of amygdalin and cyanide, so enjoy! But for pollinators visiting the flowers of an almond tree, life is not so easy. The nectar of an almond flower contains small amounts of amygdalin and it is poisonous to birds and mammals.

Scientists at the University of Haifa in Israel have been to trying to work out why a plant would risk poisoning its pollinators. Bees, rather than birds or mammals, are the most common pollen carriers so they exposed honey bees to nectar with varying concentrations of amygdalin.

Instead of being worried by the potential poison, the bees actually preferred the dosed up pollen – in fact the more amygdalin the better.

The researchers suggest two possible explanations. Maybe this chemical is an good attractant for insects so the fact that it knocks off a bird or mammal in the process doesn’t matter as long as the most important pollinators, bees, visit the flowers. Alternatively the flowers might be actively discouraging inexpert pollinators.

A third mechanism, the focus of further study for the group, is that amygdalin kills harmful bacteria and helps protect the quality of the nectar. The fact that it poisons mammals and birds is an inadvertent consequence of successfully attracting more insects over a longer period of time.

The lead scientist, Professor Ido Izhaki, points out that there are practical applications to understanding how the flowers interacts with its pollinators, particularly when, as now, pollinators are in short supply. In fact beehives from Australia are transported each year to California to help with almond pollination.

Image: A giant (unpoisoned) bee carrying pollen - a sculpture at the Eden Project in the UK.

Wednesday, 3 February 2010

Thermal Fingerprint Saves Seeds and Time

Scientists from UK and Austria have developed a new way to find out whether seeds are dead or alive, without killing them!

It’s one of the frustrating realities of seed testing that the best way to find out if a seed is still viable is to kill it. Of course if you have enough seed, this is fine, because you can test just a few of the batch. If you have a rare species, anything you can do to avoid losing a single seed is a good thing.

Isle Kranner from the Royal Botanic Gardens Kew’s Millenium Seed Bank and Gerald Kastberger from the University of Graz in Austria found that subtle changes in temperature reflect the health of the seed embryo. (They’ve apparently published their results online in the Proceedings of the National Academy of Sciences, but I couldn’t track down the paper today – my information comes mostly from a media release on EurekAlert!)

The seeds are watered and the temperature changes measured using an infrared camera. Water causes sugar inside the seed to dissolve and the seed cools down by about 2 or 3 degrees C. The important discovery was that the cooler temperature was maintained for longer by healthy seeds because they begin breaking down storage starch into sugars. If found to be alive and well, the tested seed can be re-dried and stored again.

Sometimes there is a delay in sugar generation and cooling as the seed goes through a repair phase, particularly in older seeds. So I gather it’s important to collect data on a particular plant or kind of seed to use this technique. So far work has focused on seeds from the garden pea, wheat and rape.

The test takes less than two hours, compared to the current best method which involves germinating the seed and watching…for up to three days.

This new technique will be a time as well as seed saver. In the NSW Seedbank at Mount Annan Botanic Garden we have nearly 10,000 collections of seed – including 38% of the State’s 6,000 or so ‘vascular’ plants and 30% of its threatened species.

To make sure each of these collections is still useful is close to a full-time job for one of our seedbank staff. We expect many of these seeds to last for a few hundred years but we have to keep checking on their health.

In case you are wondering, the oldest viable seeds known were probably from lotus in a now-dry lake bed in China. 466 year-old seeds germinated and grew to mature plants, albeit a little weakly. Older seeds – some thought to be 1200 years old – germinated but died soon after.

Stories circulate about much older seeds springing back to life but seem to be unfounded. 2,000 year-old Date Palm seeds germinated but I don’t think they survived very long. 10,000 year-old lupin seeds discovered in Arctic lemming burrows looked good but wouldn’t germinate. Seeds found in Egyptian tombs I understand are always carbonised and non-viable.

Seeds do have a life expectancy, and that varies from species to species, and from a few days to a few hundred years it seems. For the relatively long-lived, we still need to test their viability so that we can be sure they remain useful for species or habitat restoration. In time we may have to germinate the banked seed to produce the next generation of seed. The more viable seed we can store, the better.

Images: At the top, Director of the Millenium Seed Bank, Paul Smith, Seed Technology Officer at the NSW Seedbank, Leahwyn Seed, and me with one of the 10,000 collections in the NSW Seedbank (photo: Simone Cottrell). Above, Seed Research Officer Amelia Martyn examining seed in the NSW Seedbank (photo: Jaime Plaza).