Plants Spring into Action

We shouldn’t take plants for granted.  They seem so slow and stationary, but actually they move and breath and carry on their lives in truly amazing ways.  Plants really show off their glory in the spring.  But how do they know, without eyes, what time it is?
    In “The science of spring,” PhysOrg explored how plants know when to spring into action when it’s time to come out of their winter slowdown.  Siburn Sung [U of Texas, Austin] found that an interplay of genes responds to the temperature.  In the lab plant Arabidopsis, he found that a special molecule named COLDAIR is repressed in winter, inhibiting the plant’s ability to produce flowers.  After 20 days of frigid temperatures, the molecule gets turned back on; but it takes another 10-20 days to prime itself for the warmth of spring.  This begs the question, though, of how genes respond to external factors, and how they measure the days.  “Well, we know that there are several things done by cold – but how? That we don’t really know yet,” Sung remarked.  Then he speculated about the evolution of flowering plants.  They evolved 150 million years ago, he claimed, but had to learn how to deal with winter relatively recently.
    Once it’s time to bloom, how do plants do it?  Scientists from Harvard and China, reporting in PNAS,¹ tried to figure that out.  “Despite the common use of the blooming metaphor, its floral inspiration remains poorly understood,” they began.  They studied an Asiatic lily and found that, contrary to earlier hypotheses about differential growth of layers, “the edges of the petals wrinkle as the flower opens, suggesting that differential growth drives the deployment of these laminar shell-like structures.”  This gave them some ideas: “This functional morphology suggests new biomimetic designs for deployable structures using boundary or edge actuation rather than the usual bulk or surface actuation.”
    In Science this week,² Sarah Wyatt celebrated plant movement by reviewing a new book called The Restless Plant by Dov Koller (Harvard, 2011).  We need to unload our childhood impressions of plants as inanimate objects, she said, and dance with the plants: “plants move.  They just do so on their own time scale and in their own way.”  With the advent of time-lapse photography, we can now appreciate their clever ways of getting around. 

The Restless Plant presents a “guided tour of plant movements.” Koller starts with the classic, rapid leaf movements of the sensitive plant and [Venus] flytrap but then provides a broader understanding of plant movement that includes growth responses, expansion of plant organs, and movements of individual cells and organelles.  The world of plants becomes a fascinating dance with many movements: contractile roots pulling a bulb into the soil; the folding of leaves and flowers at nightfall; leaves and flowers tracking the Sun; roots searching for water and nutrients; the explosion of seeds into the world at large; and growth responses to light, gravity, water, temperature, and touch.

Wyatt referenced Roger Hangarter’s Plants-in-Motion web site that has time-lapse videos of plant movements (the one of morning glory twining is pretty cool); the site actually includes an educational green-screen tutorial on how students can actually dance with time-lapse videos of plants in motion.  Wyatt also referred to David Attenborough’s TV episode, “The Private Life of Plants,” parts of which are viewable on YouTube.
    Wyatt described plant movements as motorized to solve the physics problems of mechanical motion:

“Motors” provide these movements, and, although the use of the term for some of the responses is not without controversy, the analogy is sound.  For more rapid, reversible movements, motors involve turgor-driven responses in specific cells (pulvini) that are filled or drained of water as needed for movement.  For the slower growth movements, the tropisms, the motors are growing cells within specific regions of the plant.

Some of the most basic things about plants remain mysterious, she said; “the roots go down and the plant goes up and nobody really knows how or why,” one botanist said.  Wyatt was clearly impressed with the “intricacies and beauty” of plant movements after reading Koller’s book.  “You will never look at plants the same way again,” she said.
    If plants are so smart, maybe they like music, too.  The Royal Philharmonic Orchestra in London is trying to find out.  PhysOrg reported that “One of Britain’s most prestigious orchestras has performed to a rather unusual audience – row upon row of plants, in an attempt to see whether the music helps them grow.”  The music, Mozart’s Eine Kleine Nachtmusik and Symphony No. 40 is available for download on QVC UK for gardeners who would like to continue the experiment.  The site includes a video clip of the orchestra playing the first movement of the 40th to its leafy audience.  Whether the plants responded is not yet known (they didn’t applaud), but human viewers will get a kick out of the unusual experiment, and will enjoy the timeless beauty of Mozart’s music while watching.

1.  Liang and Mahadevan, “Growth, geometry, and mechanics of a blooming lily,” Proceedings of the National Academy of Sciences, published online before print March 21, 2011, doi: 10.1073/pnas.1007808108.
2.  Sarah Wyatt, “Plant Science: A Ballet of Plant Movement,” Science, 25 March 2011: Vol. 331 no. 6024 p. 1520, DOI: 10.1126/science.1203705.

Evolutionists are clueless about the evolution of plants (12/30/2010, 09/22/2010, 07/03/2009), so run them out of symphony hall so they won’t upset the daisies.
    Moody Institute of Science made one of their most beautiful and intriguing films about plant movements back in the 1990s: Journey of Life (available from Christian Book.com and Amazon).  Parts of this were also incorporated in Wonders of God’s Creation (see Moody Publishers).  Get these evergreen videos for your home library, and then get into the garden or forest and look at your fellow travelers on God’s green Earth with new appreciation.