Rucete ✏ Biology In a Nutshell
1. Primary Growth
- Refers to the elongation of the plant (increase in length).
- Occurs at the apical meristems (tips of roots and shoots).
- Responsible for the formation of herbaceous (non-woody) structures.
a) Zone of Cell Division
- Located at the root and shoot tips.
- Meristematic cells divide actively by mitosis to produce new cells.
b) Zone of Elongation
- Cells absorb water and elongate, causing the root or shoot to grow longer.
- This zone is responsible for visible growth.
c) Zone of Differentiation (Maturation)
- Cells specialize into various tissues such as:
- Epidermis
- Cortex
- Primary xylem and phloem
2. Secondary Growth
- Refers to the increase in thickness (girth) of the plant.
- Occurs in woody plants like conifers and dicot trees.
- Takes place in lateral meristems (not apical).
a) Vascular Cambium
- Produces secondary xylem (wood) and secondary phloem.
- Contributes to vascular tissue expansion.
b) Cork Cambium
- Produces the periderm, which replaces the epidermis in older stems.
- Forms part of the protective outer bark.
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Biology in a nutshell