[Not just cheap rhetoric, actually really fascinating. Looked at very closely, plants are kind of like the alternative life forms that sci-fi writers dream about, moving too slowly for anyone to notice the richness of their lives.]
http://www.nytimes.com/2009/12/22/science/22angi.html
The New York Times
December 22, 2009
Basics
Sorry, Vegans: Brussels Sprouts Like to Live, Too
By NATALIE ANGIER
I stopped eating pork about eight years ago, after a scientist happened
to mention that the animal whose teeth most closely resemble our own is
the pig. Unable to shake the image of a perky little pig flashing me a
brilliant George Clooney smile, I decided it was easier to forgo the
Christmas ham. A couple of years later, I gave up on all mammalian
meat, period. I still eat fish and poultry, however and pour eggnog in
my coffee. My dietary decisions are arbitrary and inconsistent, and
when friends ask why I'm willing to try the duck but not the lamb, I
don't have a good answer. Food choices are often like that: difficult
to articulate yet strongly held. And lately, debates over food choices
have flared with particular vehemence.
In his new book, "Eating Animals," the novelist Jonathan Safran Foer
describes his gradual transformation from omnivorous, oblivious slacker
who "waffled among any number of diets" to "committed vegetarian." Last
month, Gary Steiner, a philosopher at Bucknell University, argued on
the Op-Ed page of The New York Times that people should strive to be
"strict ethical vegans" like himself, avoiding all products derived
from animals, including wool and silk. Killing animals for human food
and finery is nothing less than "outright murder," he said, Isaac
Bashevis Singer's "eternal Treblinka."
But before we cede the entire moral penthouse to "committed
vegetarians" and "strong ethical vegans," we might consider that plants
no more aspire to being stir-fried in a wok than a hog aspires to being
peppercorn-studded in my Christmas clay pot. This is not meant as a
trite argument or a chuckled aside. Plants are lively and seek to keep
it that way. The more that scientists learn about the complexity of
plants -- their keen sensitivity to the environment, the speed with
which they react to changes in the environment, and the extraordinary
number of tricks that plants will rally to fight off attackers and
solicit help from afar -- the more impressed researchers become, and
the less easily we can dismiss plants as so much fiberfill backdrop,
passive sunlight collectors on which deer, antelope and vegans can
conveniently graze. It's time for a green revolution, a reseeding of
our stubborn animal minds.
When plant biologists speak of their subjects, they use active verbs
and vivid images. Plants "forage" for resources like light and soil
nutrients and "anticipate" rough spots and opportunities. By analyzing
the ratio of red light and far red light falling on their leaves, for
example, they can sense the presence of other chlorophyllated
competitors nearby and try to grow the other way. Their roots ride the
underground "rhizosphere" and engage in cross-cultural and microbial
trade.
"Plants are not static or silly," said Monika Hilker of the Institute
of Biology at the Free University of Berlin. "They respond to tactile
cues, they recognize different wavelengths of light, they listen to
chemical signals, they can even talk" through chemical signals. Touch,
sight, hearing, speech. "These are sensory modalities and abilities we
normally think of as only being in animals," Dr. Hilker said.
Plants can't run away from a threat but they can stand their ground.
"They are very good at avoiding getting eaten," said Linda Walling of
the University of California, Riverside. "It's an unusual situation
where insects can overcome those defenses." At the smallest nip to its
leaves, specialized cells on the plant's surface release chemicals to
irritate the predator or sticky goo to entrap it. Genes in the plant's
DNA are activated to wage systemwide chemical warfare, the plant's
version of an immune response. We need terpenes, alkaloids, phenolics
-- let's move.
"I'm amazed at how fast some of these things happen," said Consuelo M.
De Moraes of Pennsylvania State University. Dr. De Moraes and her
colleagues did labeling experiments to clock a plant's systemic
response time and found that, in less than 20 minutes from the moment
the caterpillar had begun feeding on its leaves, the plant had plucked
carbon from the air and forged defensive compounds from scratch.
Just because we humans can't hear them doesn't mean plants don't howl.
Some of the compounds that plants generate in response to insect
mastication -- their feedback, you might say -- are volatile chemicals
that serve as cries for help. Such airborne alarm calls have been shown
to attract both large predatory insects like dragon flies, which
delight in caterpillar meat, and tiny parasitic insects, which can
infect a caterpillar and destroy it from within.
Enemies of the plant's enemies are not the only ones to tune into the
emergency broadcast. "Some of these cues, some of these volatiles that
are released when a focal plant is damaged," said Richard Karban of the
University of California, Davis, "cause other plants of the same
species, or even of another species, to likewise become more resistant
to herbivores."
Yes, it's best to nip trouble in the bud.
Dr. Hilker and her colleagues, as well as other research teams, have
found that certain plants can sense when insect eggs have been
deposited on their leaves and will act immediately to rid themselves of
the incubating menace. They may sprout carpets of tumorlike neoplasms
to knock the eggs off, or secrete ovicides to kill them, or sound the S
O S. Reporting in The Proceedings of the National Academy of Sciences,
Dr. Hilker and her coworkers determined that when a female cabbage
butterfly lays her eggs on a brussels sprout plant and attaches her
treasures to the leaves with tiny dabs of glue, the vigilant vegetable
detects the presence of a simple additive in the glue, benzyl cyanide.
Cued by the additive, the plant swiftly alters the chemistry of its
leaf surface to beckon female parasitic wasps. Spying the anchored
bounty, the female wasps in turn inject their eggs inside, the
gestating wasps feed on the gestating butterflies, and the plant's
problem is solved.
Here's the lurid Edgar Allan Poetry of it: that benzyl cyanide tip-off
had been donated to the female butterfly by the male during mating.
"It's an anti-aphrodisiac pheromone, so that the female wouldn't mate
anymore," Dr. Hilker said. "The male is trying to ensure his paternity,
but he ends up endangering his own offspring."
Plants eavesdrop on one another benignly and malignly. As they
described in Science and other journals, Dr. De Moraes and her
colleagues have discovered that seedlings of the dodder plant, a
parasitic weed related to morning glory, can detect volatile chemicals
released by potential host plants like the tomato. The young dodder
then grows inexorably toward the host, until it can encircle the
victim's stem and begin sucking the life phloem right out of it. The
parasite can even distinguish between the scents of healthier and
weaker tomato plants and then head for the hale one.
"Even if you have quite a bit of knowledge about plants," Dr. De Moraes
said, "it's still surprising to see how sophisticated they can be."
It's a small daily tragedy that we animals must kill to stay alive.
Plants are the ethical autotrophs here, the ones that wrest their meals
from the sun. Don't expect them to boast: they're too busy fighting to
survive.