Nature comes in various shapes – some straight and some curved.
We all know how to create a curved shape. Children use the palms of their hands to shape cookie dough into round balls. Pastry chefs use a rolling pin to shape a round and flaky pie crust. And pitchers put a “topspin” on a baseball to throw a curve ball. But what about green plants? What’s their trick? How do they create a curve of a leaf, a petal or even a seedpod?
To see what I mean, check out this photo of a toyon leaf. Note the shape – long, elliptical-shaped, which becomes narrower towards the tip.
Now take a look at these photos of a tree poppy blossom. Note how the petals fan out and get wider, the further they get from the center. Note, too, the rounded outer edge.
Finally, look at this photo of a maple seed pod. On first glance, the shape looks elliptical, like the toyon leaf. But if you take a closer look, you can see the fine lines and how they curve at a 90 degree angle.
As you compare theses photos, you begin to see that plants do not create curved shapes like we use a biscuit cutter. Rather, shape is the result of dynamic factors that change over time. One of these factors is the plant hormone auxin.
Auxin regulates plant growth, so it makes sense that both the location, amount and movement auxin will affect both where and how much growth occurs and the shape that results from that growth.
Researchers from the John Innes Centre in the UK have been studying this question for several years. In a recently published study, they found that auxin is “is transported around plant cells in specific directions. This directional movement of auxin, called polar auxin transport, is determined by where PIN proteins – which move auxin out of plant cells – are located in cell membranes.” When the movement model (also known as the “polarity field”), is convergent this results in an elongated shape that converges near the tip – like an elongated leaf. But when the polarity field is a “divergent model” – one in which the polarity field fans outward” – the shape becomes rounded, like a petal.
And when the shape takes a right turn, like in the maple seed? I dunno – perhaps this is the plant equivalent throwing a curve ball.
This Friday, March 14, we are celebrating Pi Day! (at 1:59 AM, to be precise). In honor of Pi Day, I invite you to eat a slice of pie for dessert.
Free Birding App. For those of you who are looking for a good birding app for your Apple cellphone or iPad, the Cornell Lab of Ornitholgy is offering a free app. Click here for more information.
Upcoming Outdoor Events:
Saturday, March 15, 8-10 am. Friendly Flyers. Are there ways we can be more “friendly” to the birds around us? Learn about our region’s birds and how our behavior can sometimes affect theirs. Beginning birders are welcome. Binoculars optional. Meet at Towsley Canyon’s front parking lot. Click here for map and directions.
New trail maps available. If you’d like to explore a bit on your own, the City of Santa Clarita has a website with trail maps of our local open spaces.
There’s also a new website for bicycle riders.
Ask Dr. Norm: Do you have questions about the flora, fauna, animals, rocks, etc. in our Santa Clarita Valley? Here’s a place for you to ask your questions. Dr. Norman Herr, Ph.D., is a professor of science and computer education at California State University, Northridge.
Tell Us About Your Hike: Here’s a new website where you can post pictures, provide feedback and make suggestions about the City of Santa Clarita’s trails and open spaces.
You can listen to stories like this every Friday morning at 7:10 a.m. on “The SCV Outdoor Report”, brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.
Or check out our Facebook page – L.A. Mountains
Source: Santa Clarita News