1. Unit 2 Plant Anatomy Horticulture
Stems
Unit 2 Plant Anatomy
Horticulture

2. Objectives Describe the purpose of the stem
Label the parts of a stem and tell what they are for
Identify various types of stem structures

3. Purpose
Conduct water and minerals from the roots to other parts of the plant
Conducts food made in the leaves to other parts of the plant
Supports leaves and reproductive structures (fruit, flowers)
Produces new leaves, flowers, and branches

4. Internal components of the stem
There are 4 major internal components of the stem
a. Xylem
b. Phloem
c. Cambium
d. Pith

5. Vascular System composed of the xylem and phloem In monocots: bundles
Xylem conducts water and minerals
Phloem conducts food (carbohydrates/ Sucrose, amino acids, and hormones)
In monocots: bundles
In dicots, form rings inside the stem. (Phloem in near the bark and the xylem is the inner ring)

8. Cambium
meristematic tissue (Growth tissue) located between the xylem and the phloem inside the stem
responsible for the stems increase in diameter as it produces more xylem and phloem.

10. Pith
stores food and moisture
the center part of the stem (dicots)

11. Outer Parts of the Stem1 Nodes
area of the stem where leaves are located
areas of great cellular activity and growth
where auxiliary buds develop into leaves or flowers

13. Internodes area between the nodes
Length varies between internodes for different reasons:
Time of season
Health of the plant
Early growth vs. later growth
Speed of growth

14. Terminal Bud:
a bud that contains cells of undeveloped leaf, stem, flower, or a mix of all.
is positioned at t the tip of the stem
sometimes forms the central leader or main trunk of the plant

15. Bud scale
tiny leaf-like structures that cover the bud before it opens and grows.
can have different shapes, sizes, and colors5.

16. Axillary or Lateral Bud
a bud that will produce a new leaf or stem
located along the side of the stem.

17. MODIFIED STEMS:
Most stems are above ground; however there are certain stems that may be below ground.
Above ground MS: crowns, stolons, spurs
Below ground MS: bulbs, corms, rhizomes, and tubers

18. Spurs a compressed fruiting branch
Short, stubby, side stems that arise from the main stem
Common on fruit trees (pears, apples and cherries)

19. Stolons
a horizontal stem that is fleshy or semi-woody and lies along the top of the ground
Runner: a specialized stem that grows on the soil surface and forms a new plant at one or more nodes.
EX. Strawberries and spider plants.

20. Tubers
Enlarged portion of an underground stem like a potato that store food for the plant
The eyes of the potato are the nodes on the stem
Each eye contains a cluster of buds

21. Rhizomes:
stem that grows horizontally at or just below the soil surface.
storage organ and means of propagation
some are compressed and fleshy: Iris
some are slender with elongated

22. Bulbs shorten; compressed underground stems
surrounded by fleshy scales
Bud at top of scale
many bulbs require a period of low-temperature exposure before they begin to send up the new plant

23. Corms shaped similar to bulbs, but do not contain fleshy scales.
Buds and shoots arise from the crown and fibrous roots are fond on the bottom of the tuberous system.

24. Scale Runner