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Are lawnmowers a thing of the past? Pill-Soon Song explains all to Celia
Clarke.
What motivated you to study photobiology?

I've always been interested in looking at life and living processes from
chemical and physical points of view. To some extent by coincidence and to
some extent by design, I became interested in living processes associated
with light. Light played a fundamental role in the origin of life and
subsequently in the evolution of living systems. There are processes of
living systems that are absolutely dependent on light, like photosynthesis
in plants and vision in animals. So, I became interested in the
photobiological aspects of living processes, which is a combination of
biology and physics.

Which is the most likely outcome of artificial photosynthesis, a fix for
increasing CO2 levels or a new energy source?

There are several ways to harness solar energy by directly fixing CO2 and
reducing it to the level of carbohydrates - in other words mimicking or
improving plant photosynthesis. Probably the most direct way is to increase
the CO2 fixation efficiency of plants, for example, by genetic engineering.
This is an important approach to harness solar energy more efficiently. But
for more artificial harnessing of solar energy, for example for solar cells,
the most common system is the photochemical splitting of water to generate
hydrogen as a fuel source. Many laboratories around the world are working in
this major research area.

How far are we from achieving anything that can compete with a fossil fuel
power station?

"With the improvement of the efficiency of energy conversion of solar cell
systems and the continued decline of fossil energy, solar cell systems will
become economically viable."

From what I understand, the question is an economic one. Right now,
artificial solar cell systems are economically not comparable with gasoline
or other naturally-produced fuels but, I think, with the improvement of the
efficiency of energy conversion of solar cell systems and the continued
decline of fossil energy they will become economically viable.

What are you working on at the moment?

I am working on how plants respond to light by regulating their growth and
development. Plants are not able to move around so they have to adapt to
environmental situations. For example, if plants are in the shade they
cannot photosynthesise efficiently and, since they cannot move into brighter
daylight, they respond to the shade light at the molecular level. The shade
light causes a set of genes to make the plants grow upwards in search of
light and that's called the shade avoidance response. All plants have this
response.

Plants have light-absorbing visual pigments, like our rhodopsin, called
phytochromes. In bright daylight the major component of light is 660nm
wavelength red light, and upon absorbing this light, one phytochrome form
transforms into another, physiologically active form. This activates certain
genes involved in growth and development and it can be switched off by
absorbing longer wavelength, 730nm, shade light. So, you have an on-and-off
switching system in plants that means they can dynamically respond to their
light environment.

You have a project involving lawn grass. What is this about?

We are applying our understanding of the shade-avoidance mechanism to
biotechnological and commercial uses. Lawn grass grows in a compact
situation - this dense growth creates shadow on its neighbours and triggers
the grass to grow vertically as fast as it can, to avoid the shade. So, you
have to mow the lawn more often. Also, if lawn grass is kept in the shade it
doesn't develop chlorophylls so it cannot photosynthesise. We are trying to
make the plants tolerate and not avoid the shade. And by tolerance, I mean
that the plants remain green and can absorb and use the shade light to
regulate their growth so that they don't have to grow as tall.

And you do this by chemically and genetically modifying the plants'
phytochromes. The phytochrome absorbs 660nm light, so it cannot effectively
absorb the 730nm shade light - as far as the plant is concerned, when it is
in the shade, it is in the dark. So we are changing the wavelength of
absorption of the phytochrome toward the wavelength of shade light. Then,
when you introduce a genetically engineered phytochrome gene into lawn
grass, the grass in the shade sees the shade light more effectively and it
grows slower. So you don't have to mow the lawn as often. It also means that
you're using up less water because you're not having such rapid growth and,
since a lot of water is good for fungal infections, you can minimise disease
too.

What lies in the future for photobiology?

I think there will be two major avenues of research. One is the fundamental
area - to understand how light affects living systems and processes. The
other avenue is applied aspects - the lawn grass is a minor example, but a
more important issue is the energy problem we are facing on the planet. One
way to improve energy production by plants is to cut down on shade
avoidance. You can shorten the stems of rice plants and corn, and this will
result in more starch in the grains. Applied photobiology could lead to
increased energy production from crop plants. There is also an area of
extremely active research called photodynamic therapy: using light in
combination with a light-absorbing, so-called photosensitiser, compound to
treat cancer and skin diseases.

The Korean government declared 2006 the 'Year of Chemistry.' What are the
aims of the program?

The Korean government is collaborating with the Korean Chemical Society to
promote chemical science among young people. This is done through
emphasising chemistry in the school curriculum and promoting a hands-on
teaching approach. As a result, many of Korean students perform very well in
the international chemistry Olympiad. In spite of all these efforts, like
many other countries, the natural sciences, including chemistry, are not
among the most popular subjects. This is why the government, chemical
society and other institutions are trying to attract young students into
sciences.

You have worked in both Korea and the US. What are the most striking
differences you have found between academic life in the two countries?

In the US, research is funded by governmental, industrial and private
agencies. In Korea most of the research is supported by governmental
agencies. Another difference is that the research done in the US is by an
individual grantee - you apply individually in most cases. But in Korea you
apply for funding as a group of researchers with some common interest and
the funding is divided.
There are pros and cons of both of these systems. In the US, graduate
students and postdocs are very well supported financially. In Korea, a
graduate student still has to worry about paying for tuition. The funding is
much more competitive in the US; from the practical point of view of getting
money to do research, the Korean situation is better.

In spite of that, I think the infrastructure is much better in the US,
including the way the faculty, the graduate students and the postdocs are
assisted by expert technical staff: secretaries, repair and maintenance
staff and so on. Overall, Korea has to improve its research environment
conditions.

PPS recently featured a United Nations Environmental Program report on
interactions between ozone depletion and climate change. In your opinion,
how much of a cause for concern is the depletion of the ozone layer?

Ozone is an extremely important factor in photobiology because skin cancer,
for example, is affected by the amount of UV radiation in sunlight and that
is determined by the depth of the ozone layer. The more information we can
get and spread to the general readership, and public eventually, the better.
One of the roles of photobiologists, photobiological societies and journals
like PPS is to let people know about the importance of the ozone layer, how
to prevent the depletion of the ozone layer and how to cope with the
increased UV radiation from the sun.

And finally, if you weren't a scientist, would you do?

I'd probably be a medical doctor. I like the idea of an eye doctor - an
ophthalmologist - which is to do with photobiology. Or a skin doctor - a
dermatologist - it's also related to photobiology, skin photobiology.

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