Leaf Bud Growth

Vegetative plant buds occur in the axil of a leaf or at the tip of a stem and are the site of an undeveloped or embryonic shoot. The buds of many woody plants are protected by a covering of modified leaves called bud scales. The bud scales enclose and protect the embyonic cells of the apical meristem which can remain dormant for extended periods. Bud scales are often covered by leaf wax and hairs which help protect the apical meristem from dessication and other environmental stresses. When the bud is released from dormancy and the new shoot grows, the scales usually drop off leaving a series of scars that demark where the new shoot growth begins.

This movie shows several days of growth of an apical bud of a Tulip tree branch in the spring after being dormant for the winter. After the bud scales unfold the new leaves that were formed from the shoot apical meristem (stem cells) unfold and expand, and the shoot tip begins to elongate producing a new season of growth.