Coleoptile (Gr. Coleo - Shell, Ptile - Feather)

The coleoptile (from the Greek words “koleo” - shell and “ptile” - feather) is a special organ characteristic of seedlings of monocotyledonous plants. This is a hollow cylindrical formation that surrounds the unexpanded leaf of the seedling.

The coleoptile is located above the embryonic root and performs a number of important functions. It protects the unexpanded leaf from mechanical damage and pests, and also helps the seedling break through the soil.

The coleoptile consists of two layers. The outer layer is a tough shell consisting of cells with thick walls. The inner layer is softer and consists of cells directed along the axis of the coleoptile.

As the seedling grows, the coleoptile begins to swell, thereby pushing the unexpanded leaf out. When the leaf unfolds, the coleoptile dies and remains on the embryonic root.

Some species of monocots, such as grasses, have very long coleoptiles that can reach several centimeters in length. Other species, such as corn, have short coleoptiles that die quickly after the leaf unfurls.

Thus, the coleoptile plays an important role in the life cycle of monocots by protecting and aiding seedling germination.