GardenDrumPlants don’t use gravity for root formation

The International Space Station has revealed that a long held theory as to why plant roots grow down into soil doesn’t actually have anything to do with gravity as previously thought.

Revolutionary scientist and father of evolution, Charles Darwin, was the first to hypothesis that the reason why plant roots grow down is partly because of the influence of gravity, a theory that’s been predominant ever since. Darwin observed that seedlings roots grew either straight down or skewed left/right when planted on sloping ground (called skewing), leading him to conclude that it was physical touch and the force of gravity that combined to orientate their roots in soil.

But new research that is boldly going where no broad bean has gone before has shattered the idea.  University of Florida professors, Anna-Lisa Paul and Robert Ferl, designed the experiments to be conducted aboard the International Space Station that have categorically proven that gravity is not necessary for root orientation. They repeated Darwin’s experiments on skewing and found that in zero gravity plants exhibit the same behaviour.

Another part of their research also looked at the way plants change their genetic expression in space. As plant grow on earth, they continually react to their environment. Adapting to a range of earthly-bound stimuli throughout their lives, plants switch on and off certain genes to cope with a changing world.

Curiously, space plants cell walls have changed their genetic structure so that the genes responsible for their formation are positioned on DNA molecules oppositely to their usual arrangement when grown on earth. Paul and Ferl are not sure what advantage this gives plants when growing in zero gravity, but future research is planned to get to the bottom of it.

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