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Home » Santa Clarita News » Environment » SCV Outdoor Report » SCV Outdoor Report: Nastic “Un”-brellas

SCV Outdoor Report: Nastic “Un”-brellas

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By Wendy Langhans

One afternoon last week, Mr. Langhans and I played hookey.  We ditched our “to do” list and took a drive out to the Antelope Valley Poppy reserve.

But before we left, we had a “discussion” about whether or not to bring umbrellas.  He’s much more worried about getting wet that I am.  As it turned out, the weather was lovely – no need for umbrellas – and it was well work the trip.

 

outdoorpoppyfield

Fields of California Poppies and the Antelope Valley Poppy Reserve

On the drive back, I noticed that the blossoms that had been wide-open were beginning to close up.  Perhaps the thought of umbrellas was still in my mind, because it seemed like the flowers were closing up like an umbrella.  I wondered – why was that?  How does this mechanism work?  What purpose does it serve?  Here’s what I found out:

outdoorpoppy

A folded-up California Poppy

There are two kinds of movement in plants:  tropisms and nastic movements.  (Sorry to disappoint you, but the apples thrown by the grumpy Apple trees in “The Wizard of Oz” don’t count.)  Tropisms are slow, growth movements towards or away from a stimulus.  As an example, think of how a plant grows towards the sunlight.  But there is a second kind of movement, which is known as a “nastic” movement.  This movement is relatively quick, cyclic or reversible, and not directed towards or away from the stimulus.  A classic example of a nastic movement is a flower that opens during the day and closes at night.

 

Speed

Type

Stimulus

Tropisms

Relatively Slow

Growth

Directed towards or away from a stimulus

Nastic Movements

Relatively rapid

Cyclic or Reversible

Not directed towards or away from a stimulus

 

So the change I saw in the poppies was a “nastic” movement.  Specifically, what I observed was a “nyctinasty” movement, caused by a change in the intensity of light.  On the drive back, there were more clouds and the sun was lower in the sky.

How do nastic movements work?  It’s sort of like opening and closing an umbrella, only instead of your hand pushing up or pulling down on the mechanical slide, the plant uses hydraulics.  Certain “motor” cells at key locations swell or shrivel with water.  When they shrivel, the plant bends towards them; when they swell, the plant bends away from them.

What purpose do these nyctinastic movements serve?  Protection.  Just like an umbrella protects us – the poppy protects its pollen from rain.  Wet pollen is heavier that dry pollen, and therefore less likely to be carried by beetles or bees.  Rain can also interfere with pollenation,  “either by washing pollen grains from the flower, or by soaking them, which kills them after a few hours.”

outdoorpoppybeetle

An open California Poppy.  Note the pollen on this beetle

Nyctinastic movements occur when there is a change in the intensity of sunlight.  This happens when clouds move in prior to a rain storm.  But unlike our umbrella, which we “open” before the rain, the poppy umbrella “closes”.  In other words, poppies carry their own nastic “un”-brella.


Upcoming Outdoor Events:

Antelope Valley Poppy Reserve. If you want to visit the Antelope Valley Poppy Reserve, here’s a link.

April 24 & 25, 10 AM – 6 PM.  California Poppy Festival, Lancaster City Park. Also, this weekend is the California Poppy Festival.

Trail Maintenance Schedule. Come join our volunteers as they help maintain our trails.  Contact Steve at machiamist@aol.com for time and place.

Wednesday mornings, April 7, 14, 21 & 28.

Saturday mornings, April 10 & 24


You can listen to stories like this every Friday morning at 7:10 a.m. on “The Hike Report”, brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.

For the complete MRCA hike and activity schedule and for trail maps, click here or go to www.LAMountains.com.

 

 

SCV Outdoor Report: Nastic “Un”-brellas

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