02-05-2005, 08:09 AM
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March 2, 1995: Vol26n19: Plants have 'memory' UB researchers find
By ELLEN GOLDBAUM
News Bureau Staff
Forewarned is forearmed and, according to UB biologists, plants are no
exception to that survival rule. Plants "remember" when they've been
attacked and they respond faster to future attacks by hastening
production of chemical defenses, Ian Baldwin, UB associate professor
of biological sciences reported Feb. 21 at the annual meeting of the
American Association for the Advancement of Science in Atlanta.
Baldwin said the research, which eventually will be useful in
developing generations of pest-resistant plants, demonstrates that
plants have a more sophisticated relationship to their environments
than is commonly thought.
"We have this idea that animals are smart, and that they have
knowledge of their environments and of predators, but we don't at all
have that perception of plants," he added.
"This research is helping us develop that perception, that
plants are individuals with histories, who perceive their environments
and who have evolved responses to those environments," he said.
Baldwin spoke at a session focusing on the pathways through
which animals and plants perceive injury or damage, and how they
respond.
The UB research supports the premise that plants defend
themselves using a chemical pathway, called a signal-transduction
pathway, that parallels the one involved when animals register damage
or injury internally and respond to it.
"Animals can run away; plants cannot," said Baldwin. "But both
plants and animals use a similar signal-transduction pathway to say
'You're damaged.'"
While animals respond to damage by producing prostaglandins
and experiencing pain, plants respond by inducing the production of
chemical defenses, Baldwin said.
To determine whether or not memory is at work in plants'
defenses, Baldwin and his colleagues needed to uncouple from the
response to the wounding.
"A key issue for unraveling the signal cascade involved in
these chemical defenses was to elicit the response to the wound
without actually wounding the plant," said Baldwin.
If the experiments had involved actually damaging the leaves,
plants would have had to be repeatedly wounded, generating significant
scar tissue and possibly resulting in a plant with no leaves.
"We needed to isolate the cue that causes the plant to produce
alkaloids (toxic chemicals plants produce defensively), so that we
could ask these questions in a much more rigorous way that isn't
confounded by the secondary aspects of wounding," Baldwin explained.
The UB researchers, the first to explore memory in whole
plants, studied a native species of tobacco, Nicotiana sylvestris.
Damage to its leaves activates production of jasmonic acid, which, in
turn, activates production of nicotine, which is toxic to pests.
To induce a defensive response, the researchers added jasmonic
acid at different intervals to the roots of plants grown in solution.
Plants were dosed with the same amount of jasmonic acid once,
twice or three times during an 18-day period, allowing six days
between inductions so that the defensive response could subside
According to Baldwin, plants that had two prior inductions
attained significant increases in their nicotine pools two days
earlier than did plants with one or no prior inductions.
"Our work shows that plants make their nicotine faster if
they've had prior exposure to the signal," said Baldwin.
Baldwin describes the memory mechanism in plants as a type of
"immunological memory."
"The reason why vaccines work in humans and animals is that
you're stimulating the immune system to remember something. In the
same way, it seems that plants do have memories from prior attacks,"
he said.
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http://www.buffalo.edu/reporter/vol26/vol26n19/2.txt
Humans are omnivorous. Humans are not carnivores or herbivores.
Until soylent green is available animales will have to do. |
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