Gravitropism - Plants programmed to Know Which Way is Up

June 28, 2011 "In a tiny corner of western Poland a forest of about 400 pine trees grow with  a 90 degree bend at the base of their trunks - all bent northward. Surrounded by a larger   forest of straight growing pine trees this collection of curved trees, or "Crooked Forest," is a  mystery.  Planted around 1930, the trees managed to grow for seven to 10 years before getting held   down, in what is understood to have been human mechanical intervention. Though why   exactly the original tree farmers wanted so many crooked trees is unknown."

Discovery News: "POLAND'S MYSTERIOUS CROOKED FOREST"

Well, some suggest that it was a tree farm planted by some unknown individual/s who formed the trees early on to grow crooked, but then the war came and the venture lost purpose. The only thing is, no one really know who planted them or what his/her purpose was. Others have said it could have been several weather phenomena possibilities. Clearly either way they were bent when very young and them later recovered. Trees living near lakes may have been effected by great ice heaves or a similar effect could occur with a great wind storm, maybe an extremely heavy blizzard, then gradually grew straight upwards again. That actually happened to one of my young leggy Torrey Pine trees up in 4600' Elevation Anza CA. Most likely it was some type of plantation as seen from the even spacing of the trees. Whatever the case, the trees nevertheless instinctively knew which way to grow by information encoded into their DNA and a term we call Gravitropism. But this curved phenomena is actually quite common out in nature especially on steep mountain slopes.

Image -  Mathieu Rodriguez

Very common site on steep slopes in a forest. Saw this many times in and around mountain slopes of the San Jacinto Mountains  near Idyllwild California. When seedlings are jest a couple inches high debris moving downwards from above and even heavy snows may bend the young seedling over. Any several inch high seedling you find you can dig down and find no root growing straight down, but rather the actual root will be above the tree. As trees mature they grow upwards as the one in the photo. However hundreds of years late there will be no noticeable curvature as the large tapering trunk base will fill out and absorb any remnant signs of a curve pattern. But again, there no doubt is some instinctive information within a seeds DNA to direct it and even correct it when necessary where to grow. Root cells just know to grow downwards which is termed Positive Gravitropism, while above ground foliage knows to defy gravity in what is known as Negative Gravitropism. In any case both foliage and root cells have specific information which allows them to have Graviperception. Aren't we glad the natural world is so organized ? Only humans have made it the exact opposite in may areas today. But lets view some pictures of what seeds know early on.

Notice that no matter what direction the seed is placed, both leaves and roots know where their assigned destination is located. This apparently has to do with  plant growth hormones called Auxins. The very term comes from a Greek word meaning to grow. These compounds have the ability to cause or induce cell elongation in stems. But interestingly, stem shoot cells require greater amounts of auxin for maximal growth, while root cells require very low concentrations for their optimal growth. Still it's all information controlled from withing their DNA from their birth at germination.

Phototropism

Anyone who has house plants will be very familiar with this mechanism called phototropism  where plants in a window will lean towards which ever directions the sun is shining from. This process may even be noticed in any forest where there so much more tree competition for light at the edge of a forest will cause a growth leaning of a smaller tree towards an open meadow from under the much older and taller giant trees and their canopy. Then there is the ever common phototropism in sunflowers where the flowers heads face and always turn towards the sun all day long. This is the first year here in Sweden I didn't grow any and yet the previous 5+ years I've witnessed this same phenomena over and over. Some industrial Solar Farms also have automated mechanical controls which mimic what sunflowers do when they turn and follow the sun in order to maximize full Sun ray potential.

California Sycamore 

This process of gravitropism is what allows often fallen trees such as Sycamores along creek beds to grow into picturesque forms we all all familiar with on our hikes. This type of scene is very common everywhere in Southern California where heavy winter storms will knock down a young to middle age Sycamore tree only to have it grow formerly side branches turn into a growth of straight upright tree trunks on the skyward side of the fallen tree. 

photo by Dale Ruthlinger

Nature wouldn't be at it picturesque best were it not for these incredible mechanisms driven by encoded information for upright correction. To sum up, these mechanisms are incredible informational driven systems which give and add to the incredible beauty of our natural world all around us. Ever notice that in nature beauty is generally the rule rather than the exception ?

*smile*