A man for all seasons

In aisle after aisle of small crates stacked from floor to ceiling are specimens of Australia’s flora - the Herbarium has one of Australia’s largest collections of pressed plant specimens. Nearly 700 specimens in particular hold historical significance: they were collected by Sir Joseph Banks in 1770 when he visited Australia with Captain Cook aboard the Endeavour.

As the Deputy Executive Director for Science and Conservation at the Royal Botanic Gardens, Summerell cares for more than 19,000 species of plants.

“We have the broadest diversity of plants that any plant pathologist would ever hope to work with, many of them are out of their normal range and perhaps growing in quite stressful conditions,” Summerell says.

In many ways, he sees the Royal Botanic Garden as a guardian of plants, and more so than ever this year, as the garden celebrates its 200th anniversary.

“We have a role in promoting why plants are important for people, what plants do for the ecosystem, why diversity of plants is important. We need to ensure people understand why they need to protect plants so they are there in the future,” he adds.

“Most people think the gardens are pretty - a nice place to walk through, a beautiful green space so close to the city. But I think people would be surprised by our science programs and the incredible range of scientific research we do here.”

This year will be Summerell’s 28th working at the Royal Botanic Garden. In that time he has seen an important shift in the plants grown there.

“When I started working here we tried to maintain a rose garden where we had to spray it with fungicides and insecticides every two weeks,” Summerell says. “Now we grow types of roses that are much more adaptable to the Sydney environment, so we don’t have to spray them at all.”

It is a lesson he believes the home gardener can draw upon.

“People should look at the changes we have made and say ‘I can do that in my own backyard’,” he says. “You can grow beautiful things in your garden and have a beautiful landscape without pesticides that have a whole range of detrimental effects.”

For someone who has been collecting plants his whole life, Summerell has found his dream job.

“As I was growing up, I was a keen collector of plants - I just really love their diversity,” he says. “Getting out into the Australian bush was something I really enjoyed.”

It was this enthusiasm that led him to study agriculture at the University of Sydney and complete a PhD under world-renowned plant pathologist Professor Lester Burgess.

“It was excellent training and set me up to look at all aspects of natural science, whether in agriculture, food security or understanding the natural ecosystem,” he says.

His partnership with Burgess has endured for more than three decades. They have been collaborating and working together as plant pathologists and are now considered Australia’s foremost experts on an emerging fungal threat.

The Fusarium pathogen could potentially wreak havoc on the Cavendish banana variety, which accounts for 95 percent of local banana production and 45 percent of all bananas grown in the world. Summerell travels internationally teaching people how to recognize Fusarium and other plant pathogens as they emerge in crops.

Perhaps the most devastating and well-known impact of a plant pathogen is the Irish potato famine in the 1840s. The potato blight ravaged potato crops in Ireland and caused Europe’s worst famine in the 19th century. Summerell says avoiding catastrophes like this is really up to consumers.

“We need to demand a greater variety of the food that we eat - different types of apples, tomatoes, bananas. When there is demand for different types of fruit and vegetables there will also be greater diversity. So that if you do get a pest or a pathogen come through, there is less likelihood it will have a devastating impact,” he says.

“The other important component is making sure organisations have a bank of different types of genotypes stored away, so that if a disaster happens there is something to go back and refer to - that’s why seed banks are really important.”

They are so important that Summerell is overseeing the largest seed bank in the southern hemisphere. Housed at the Australian Botanic Garden, at Mount Annan in Sydney’s southwest, the facility includes state-of-the-art refrigerated vaults; one that can store seeds at 4 degrees Celsius; and another that can store them at minus-20 degrees.

After graduating from the University of Sydney almost 30 years ago, he is back at the University as an adjunct professor inspiring the next crop of plant pathologists - just as his PhD supervisor, Burgess, inspired him.

Australia has already needed to tap into this insurance policy to bring a plant species back from extinction. During the 2009 Black Saturday bushfires in Victoria, the world’s only population of the shining Nematolepis shrub was destroyed.

Thankfully, some cuttings and seeds of the plant had been collected before the fires and were successfully replanted at their original site.

The seed bank is part of a global initiative known as the Millennium Seed Bank Partnership. The initiative’s aim is to have 20 percent of the world’s flora stored in seed banks by 2020.

“If we can put the seeds in the seed bank and have it preserved properly, then we would at least have an insurance policy for protecting that particular species,” Summerell says.

“Humanity needs to stop the amount of species we are destroying and wiping off the planet.”

As he talks about the importance of the seed bank project, Summerell’s love for plants and the natural ecosystem is obvious, and he shares it through teaching.

Written by Sally Sitou
Photography by Victoria Baldwin (BA ’14)