Another plant Word of the Day

[Guest guest]

" Not that I want to be a god or a hero. Just to change into a tree,

grow for

ages, not hurt anyone. " Using trees as the metaphor, these poignant

words

of Nobel prizewinner Czeslaw Milosz sum up what it truly means to be

human.

Perhaps we in the animal kingdom can learn much from those in the

plant

kingdom.

This week we feature words related to trees and plants, and as today's

example shows, we don't have to keep these terms only for our leafy

friends.

One can use many of these words in other contexts, alluding to human

behavior.

tropism (TRO-piz-uhm) noun

The turning or bending (typically by growth instead of movement)

of an organism in response to an external stimulus.

[From Greek tropos (turning). Ultimately from Indo-European root trep-

(to turn) that also gave us troubadour, tropic, entropy, and

contrive.]

If you've ever noticed a plant bending towards the light, you've seen

an

example of tropism. The term is usually applied to plants. The

response to

a stimulus could be positive or negative: towards or away from the

stimulus.

Some examples of stimuli are light (phototropism), gravity

(geotropism),

heat (thermotropism), touch (thigmotropism), and water (hydrotropism).

Darwin and his son Francis demonstrated that the tip of the plant

detected

light and if you covered just the tip, the plant would grow straight,

not

toward the light.

The word tropism is related to trope, the term for rhetorical devices

such

as metaphor and irony. The idea is that the words in those rhetorical

devices are turned in a special way.

" The traits [Judith ] has drive many reporters at The Times

crazy:

her tropism toward powerful men, her frantic intensity, and her

peculiar

mixture of hard work and hauteur. "

Maureen Dowd; Woman of Mass Destruction; The New York Times; Oct

22, 2005.