In botany, the radicle is the first part of a seedling (a growing plant embryo) to emerge from the seed during germination. The radicle is the embryonic root of the plant, and grows downward in the soil. Above the radicle is the embryonic stem or hypocotyl, supporting the cotyledon(s).

The radicle emerges from a seed through the micropyle. Radicles in seedlings are classified into two main types. Those pointing away from the seed coat scar or hilum are classified as antitropous, and those pointing towards the hilum are syntropous.

If the radicle begins to decay, the seedling undergoes preemergence damping-off. This disease appears on the radicle as darkened spots. Eventually, it causes death of the seedling.