hyponasty

[ hahy-puh-nas-tee ]

noun

, Botany.

1. increased growth along the lower surface of a plant or plant part, causing it to bend upward.

hyponasty

/ ˈhaɪpəˌnæstɪ /

noun

1. increased growth of the lower surface of a plant part, resulting in an upward bending of the part Compare epinasty

Derived Forms

• ˌhypoˈnastically, adverb
• ˌhypoˈnastic, adjective

Other Words From

• hypo·nastic adjective
• hypo·nasti·cal·ly adverb

Word History and Origins

Origin of hyponasty¹

1870–75; hypo- + Greek nast ( ós ) pressed close, compact + -y ³

Example Sentences

Circumnutation modified through innate causes or through the action of external conditions—Innate causes—Climbing plants; similarity of their movements with those of ordinary plants; increased amplitude; occasional points of difference—Epinastic growth of young leaves—Hyponastic growth of the hypocotyls and epicotyls of seedlings—Hooked tips of climbing and other plants due to modified circumnutation—Ampelopsis tricuspidata— Smithia Pfundii—Straightening of the tip due to hyponasty—Epinastic growth and circumnutation of the flower-peduncles of Trifolium repens and Oxalis carnosa.

From Project Gutenberg

The movements thus induced result from a modified form of circumnutation; for, as we shall immediately see, an organ under the influence of epinasty does not generally move in a straight line downwards, or under that of hyponasty upwards, but oscillates up and down with some lateral movement: it moves, however, in a preponderant manner in one direction.

From Project Gutenberg

This shows that there is some growth on all sides of the part, but more on the upper side in the case of epinasty, and more on the lower side in that of hyponasty, than on the other sides.

From Project Gutenberg

At the same time there may be in addition, as De Vries insists, increased growth on one side due to geotropism, and on another side due to heliotropism; and thus the effects of epinasty or of hyponasty may be either increased or lessened.

From Project Gutenberg

As the rectangularly bent portion of an upright stem grows older, the lower part straightens itself; and this is effected through hyponasty.

From Project Gutenberg