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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Video: How Cucumber Tendrils Curl
30 August 2012 2:00 pm
In 1865, Charles Darwin noted that the spiraling tendrils of the cucumber plant allow it to act in un-plantlike ways. By reaching for and grasping a support, then hoisting it toward the sun, tendrils allow the plant to move. Once tethered, the tendrils coil into a helix, shown in this video. Darwin theorized that the spiral acts like a spring, but noticed that unlike a classic spring, which curls in one direction only, cucumber tendrils wind in opposite directions from the tethered ends, forming a kink in the middle. Now, a team of scientists has figured out just how, and why, the cucumber tendril coils in this fashion. By observing the tendrils' formation and mimicking their structure with mechanical and mathematical models, the researchers found that after the tendril grasps its support, a thin, two-layer ribbon of gelatinous cells shrink on one side as they lose moisture, but not on the other. This asymmetric contraction causes the fiber to wind in opposite directions, creating a spring that may stabilize the plant against large disturbances while permitting it to gently move with small forces, like a gentle breeze. When pulled from either side, the fiber does not unwind like a normal spring, but actually winds tighter. Young, moist tendrils do not tend to overwind, the researchers report online today in Science, but mature, dry tendrils do—helping to explain how delicate tendrils gradually stiffen to support a vine laden with cucumbers.
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