1. PLANTS – DAY 3
MONOCOT & DICOTS

2. INTRODUCTION
There are different classes of plants – one of these classes of plants are called angiosperms, and these plants produce flowers.
Angiosperms can be further divided into 2 subclasses: Monocotyledoneae and the Dicotyledoneae, aka monocots and dicots
Names of 2 subgroups are based on structure of their seeds

3. SEEDS
The seed, which surrounds the plant embryo and protects it from desiccation in the uncertain conditions of a terrestrial environment, is one of the adaptations that has allowed plants to thrive as they gradually moved from water to land.
Each seed consists of an embryo, food source, and protective outer coat; it can lie dormant for some time before germinating, waiting until environmental conditions are right
Monocots have only 1 seed leaf, cotyledon
Dicots have two cotyledon or seed leaves
Cotyledons store nutrients/carbohydrates that nourish the embryo of the plant as it develops. Cotyledons are often the first leaf to appear as the seed germinates

4. MONOCOT & DICOT SEEDS

5. EXAMPLES OF MONCOTS & DICOTS:
MONOCOTS:
Onion, corn, rice, sugarcane
DICOTS: tomatoes, cabbage, apples, peaches

6. SUMMARY OF DIFFERENCES:
MONOCOTS
DICOTS

7. TISSUE TERMS
Vascular cambium/cylinder: meristematic tissue responsible for creating new xylem and phloem tissue
Pith: the parenchyma tissue at the very center of roots AND stems. Functions in storage of nutrients, carbohydrates and water
Cortex: parenchyma tissue surrounding the pith; made of rigid cells in roots AND stems
Pericycle: a thin layer of lateral meristematic cells that surrounds the vascular cylinder; helps for secondary roots to grow
Endodermis: layer of rectangular cells surrounding the vascular cylinder; innermost layer of the cortex; regulates movement of water and minerals
Epidermis: the outermost layer of a multicellular plant experiencing growth
Vascular Bundles: collections of xylem and phloem tissue, separate from other collections of cells, running longitudinally - includes xylem and phloem

8. ROOT TISSUE DIFFERENCES
Xylem in center of root in an ‘X’ shape; phloem is outside of xylem
Vascular bundles are arranged in a ring shape

9. MONOCOT ROOT CROSS SECTION

10. DICOT ROOT CROSS SECTION
CORTEX
EPIDERMIS

11. STEMS – MONOCOT & DICOT

12. DICOT STEM CROSS SECTION
In herbaceous dicots, bundles are arranged in a ring
A thin layer of tissue called vascular cambium between xylem and phloem – can appear as a hollow area in the plant (buttercup)

13. MONOCOT STEM CROSS SECTION
MONOCOT STEM VASCULAR BUNDLE
Herbaceous monocots have vascular bundles scattered throughout the stem (corn)