Macro Monday

Oooooh, look at me, actually posting a Macro Monday photo on Monday - just. Will wonders never cease?

So, anyone care to guess what plant is growing this tendril?

This was going be my shortest post ever, but, well, I can't quite help myself. So here are a few tantalising tidbits about tendrils:

• Tendrils are formed from modified shoots, leaves or auxillary branches.
• They form following physical touch, turning towards the object touched. This change in growth direction is known as thigmotropism.
  
• The touch is sensed by tiny hairs on the surface of the plant.
  
• The change in direct of growth is caused by a change in turgor of the plant cells (those on the touch side lose water and become flaccid, while those on the opposite side fill with water and become much firmer).
• Differential growth also occurs in response to hormones such as auxins. Cells on the side furthest from the touch elongate more than those on the side closest to the touch, causing the tendril to turn towards the touch.
• And finally, guess who first studied such movements. Oh yes, it is him again, that most prolific and famous of biologists, Charles Darwin himself. He published his monograph On the movements and Habits of Climbing Plants in 1865. I suppose he had to keep himself busy once he had finished On the Origin of Species.
  

Here endeth the lesson.

And here is a link to Macro Monday.