Figure One

Science. Communication. Community.

The revenge of the touch-me-nots

IMG_3489I am not a violent person. I flinch during action scenes and put off removing band-aids. But this summer, on my honeymoon in India, I finally got in touch with my inner-thug.

My husband Raj and I went to a quiet, lush area known as Kerala, because all couples go to Kerala. Bright rice patties (lined with cell phone company ads) dominated the landscape. Here and there, dry land offered other kinds of fauna a perch. One delicate little plant hugged the slopes near our hotel. Tiny pairs of leaves, each wide open to the sun, lined the plant’s delicate branches.

“Flick it,” said Raj, who’s no stranger to India or its wildlife.

Obediently, I flicked. Immediately the leaves nearest my attack folded downwards. Then the pair just below them and on down the line. Even the branches themselves folded down in submission. These were live dominoes! And there were hundreds of them on this very hillside alone, just asking for it.

Poor Raj. For the rest of the trip, romance took a back seat. In my mind, every excursion became a hunt for touch-me-nots to torment.

Fortunately, other people’s fascination with touch-me-nots has taken a more productive form. I’m indebted to Daniel Chamovitz, author of What a Plant Knows, for summarizing what’s been learned about how Mimosa pudica moves with out muscles.

As with humans, touch triggers an electrical signal. It travels the length of an M. pudica leaf, reaching a group of cells called the pulvinus. These cells control water pressure in the leaves. When trouble strikes, the water pressure drops, and the leaves fold inward.

This change is chemically choreographed. On good days, a leaf’s pulvinas cells are full of potassium ions, creating an imbalance (in charge) with their environs. Water flows in to dilute the potassium, making the leaf firm and erect. A “danger” signal causes potassium gates in the pulvinas to open. When they do, both the potassium ions and the water they attract make a hasty exit.

I was happy to learn this. But I was thrilled to find touch-me-not seeds at my local hardware store. I snatched up three packs and immediately set the seeds soaking in a glass on my desk, where I could watch them sprout. Soon, I could have a good flick any time I wanted it.

But I had underestimated my adversary and its ally, a dark and stormy night.

When I awoke the next day, my computer stood in a pool of water, its screen emitting meaningless bursts of light. The attack had been swift and targeted. The cup holding the touch-me-not seeds had been toppled directly onto my laptop, rendering it witless. It was then I knew that my deeds in India had not gone unpunished.


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This entry was posted on May 2, 2013 by in Uncategorized and tagged .
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