MARTIN SHIELDS / SCIENCE PHOTO LIBRARY MARTIN SHIELDS / SCIENCE PHOTO LIBRARY
Pea (Pisum sativum) seedling recently germinated. The radicle (first root) has emerged from the seed and is now visible as the primary root with secondary roots branching off. The primary root merges into the hypocotyl (stem below the cotyledons). The primary root grows down while the hypocotyl has lifted the cotyledons upward. As the root-shoot axis continues to develop the epicotyl will grow upward above the cotyledons. The first true leaves are seen emerging from between the cotyledons.
Model release not required. Property release not required.