Stem structure and functions

Stem structure:
I. Main functions of stems
A. Support
B. Conduction of water and nutrients
C. Storage
D. Production of new living tissue

II. Stem growth in angiosperms - dicots and monocots:

A. Tissues develop from apical meristem and differentiate into dermal, ground and vascular tissues
B. Stem tissues:
- Dermal tissue:
1) Epidermis - covered by a cuticle
2) Can have chloroplasts (esp. guard cells of stomatal apparatus)
3) Later it developes into a "bark"

- Ground tissue

Two parts in dictos:
a) Cortex - outer part
b) Pith - inside region

- Vascular tissues
1) Phloem - outside
2) Xylem - inside

III. Differences between dicots and monocots, in monocots:
1. Arrangement of vascular bundles is scattered
2. Pith and cortex cannot be defined
3. Very few species undergo secondary growth (lack a vascular cambium)

IV. Secondary growth:
1. Vascular: Secondary xylem to the inside; secondary phloem to the outside
2. Cork: Phellem to the outside and phelloderm to the inside (bark consists of phellem and phelloderm)