MARTIN SHIELDS / SCIENCE PHOTO LIBRARY MARTIN SHIELDS / SCIENCE PHOTO LIBRARY
Corn, Zea mays, seedling recently germinated and illustrating gravitropism (geotropism). The three seeds were germinated at different orientations and in the dark. The one on the left was upside down, the middle seed was right-side up and the one on the right was sideways. Nevertheless, in each case the root is growing downwards (positive gravitropism) and the shoot upwards (negative gravitropism). The emerging plants oriented themselves correctly without any cue from the sun - they responded to gravity.
Model release not required. Property release not available.