Apical Bud Under the Microscope (Longitudinal Section)
Apical Bud (Longitudinal Section), Hydrilla verticillata
This is a lengthwise slice through the growing tip of a Hydrilla shoot, a water plant, stained with safranin. It shows where new leaves and stem tissue are made, which makes it a classic slide for teaching plant growth.
A longitudinal section of a terminal apical bud (Apical bud L.S.) stained pink/magenta with Safranin, demonstrating primary shoot development and apical dominance structures in an aquatic angiosperm. At the tip, the dome-shaped shoot apical meristem (SAM) is composed of actively dividing, unspecialized meristematic cells with dense cytoplasm and prominent nuclei. Flanking the apical dome are successive stages of arching leaf primordia and developing young leaves that overlap to form a protective terminal envelope. In the axils of young leaves, developing axillary bud primordia can be seen, while procambial strands extend downward along the stem axis, marking the initial differentiation of primary vascular tissue within the central stem axis.
What to look for
- Shoot apical meristem: A small dome of tightly packed cells at the very tip, where cells divide to make new tissue.
- Leaf primordia: Small bumps and young leaves curving up around the dome, getting larger farther from the tip.
- Axillary bud primordia: Small clusters of cells tucked where young leaves meet the stem, which can later grow into side branches.
- Procambium: Narrow strands of long cells in the center of the stem that will become xylem and phloem.
At each magnification
Low power (about 4x)
The pointed shoot tip with young leaves overlapping around it, all in shades of pink to red.
Medium power (about 10x)
The meristem dome and the sequence of leaf primordia, from tiny bumps to larger leaves.
High power (about 40x)
Small, densely stained meristem cells with large nuclei compared with older cells lower down.
Questions and answers
What is the shoot apical meristem and where is it on the slide?
The shoot apical meristem is the group of dividing cells at the very tip of a stem. On a longitudinal section of an apical bud, it is the small dome at the top, surrounded by young leaves that grew out from its sides.
What are leaf primordia?
Leaf primordia are the earliest stages of new leaves. They start as small bumps on the side of the meristem and grow larger as they get farther from the tip.
Why use Hydrilla for an apical bud slide?
Hydrilla has a simple, slender shoot tip with many closely spaced leaves, so one section shows the meristem and several stages of leaf development at once.
- Category
- Botany & Plants
- Scan magnification
- 20x
- Stain
- Safranin
- Tags
- apical bud, apical bud longitudinal section, shoot apical meristem, leaf primordia, axillary bud primordium, procambium
Viewing this slide in class
This is a scan of a real prepared slide, not a simulation or a drawing. On StudyScope you can pan from the whole slide down to individual structures, always in focus, and measure them in real micrometers with the calibrated ruler. Present it live and every student screen follows your view and annotations. Students join with a room code on Chromebooks, iPads, or any browser, with no accounts.