1. Bio 108
Plant Physiology
Mariedel Isulat, PhD

2. Course Outline
I. Introduction
Overview of Plant Structure
Plant Cells
II. Transport and Translocation of Water and Solutes
Water and Plant Cells
Water Balance of the Plant
Mineral Nutrition
Solute Transport
III. Biochemistry and Metabolism
Photosynthesis : The Light Reactions
Photosynthesis : The Carbon Reactions
Photosynthesis : Physiological and Ecological Considerations
Translocation in the Phloem
Respiration and Lipid Metabolism
Assimilation of Mineral Nutrients
Secondary Metabolites and Plant Defense

3. IV. Growth and Development
Gene Expression and Signal Transduction
Cell Walls : Structure, Biogenesis and Expansion
Growth and Development
Phytochrome and Light Control of Development
Blue-lIght Responses : Stomatal Movement and Morphogenesis
Auxin : The Growth Hormone
Gibberelins : Regulators of Plant Height
Cytokinins : Regulators of Cell Division
Ethylene : The Gaseous Hormone
Abscisic Acid : A Seed Maturation and Anti-stress Signal
The Control of Flowering
Stress Physiology
C

4. Major Design Elements of Plants
1. Ultimate solar collectors
2. Non-motile but move towards essential
resources
3. Structurally reinforced to support their mass
4. Continuously lose water by evaporation but
have mechanisms to avoid dessication
5. Have mechanisms for moving water ,
minerals and photosynthetic products

5. Plant Structure

7. Categories of Plants
Gymnosperms
-less advanced; pine, fir, spruces, redwood ( 700 known species)

8. Angiosperms
-more advanced, about 250,000 known species

9. Plant Structure
1. Plant Cells are sorrounded by cell walls.
middle lamella – cement
primary and secondary cell walls
2. New cells are produced by meristem
apical meristem – tips and axillary buds
pericycle – where lateral roots arise
primary growth – from apical meristem
secondary growth – from lateral meristem
vascular cambium –gives rise to secondary
xylem and phloem
cork cambium – produces the periderm made up of
cork cells
3. There are three major tissue systems in plants : Dermal,
Ground, Vascular

10. Cell Walls
Components : cellulose
pectin- resist compression
glycan – tensile strength
Primary cell wall – growing and dividing cells
- provide mechanical strength and allows
growth and development
Secondary Cell Wall – much thicker, deposited after
cells ceased to grow

11. Secondary Cell Walls

12. Meristem
Apical meristem

14. Fluid-mossaic Model : Cell Membrane

16. Chapter 1: Plant Cells Guide Questions
Features of Flowering plants:
1. Algae to Ferns : water independence
Dessication resistance
2. Vascular tissues
3. Seeds for reproduction ( with endosperm)
4. Flowers ( petals, ovary)
innovative dispersal of gametes and progeny

17. Roots
Regions of a Root:
1. Root cap - protect the apical meristem and to penetrate the soil
2. Apical meristem - the growth region of the root
lower side- produces new root cap
upper side- produces new growth cells for root growth
3. Elongation region – region for increase in the length of the root
4. Root hair region – where many epidermal cells develop lateral
protrusions called root hairs which serve to increase surface area for
better absorption
5. Mature region - the region where cork begins to replace epidermal
cells ; has reduced ability to absorb water and minerals

19. Stems
Features :
1. Nodes - the points on a stem where a leaf or
leaves are attached
2. Internodes - intervals between the nodes
Although the root and stem share many
common structural features, the root bears no
appendages comparable to leaves, and
consequently, has no nodes or internodes.

20. Types of root systems:
1. Tap Root System - Smaller roots are
organized around a large central root
2. Fibrous Root System - A mass of small
adventitious roots as large as the primary
root.

21. Types of roots:
1. Primary - The primary, or seed root, is the first root formed
by a sprouting seed.
2. Adventitious - Roots originating from something other than
root tissue, such as the lower portion of the stem.
Aerial - Adventitious roots developing above
ground with specialized functions such as
the climbing or hold-fast roots of some
vines.

22. Three main stem types:
1. Herbaceous stems
- have very little woody tissue
- with a single-layered epidermis which secretes
a waxy cuticle onto its outer wall.
- live for different lengths of time:
2. Woody stems
- have a high percentage of woody tissue.
wood of a tree - the xylem portion of the stem, as it
becomes more massive by further secondary
growth,
bark – tissues outside the wood and the cambial layer
3. Shrub has several woody stems growing from a single base.

23. Tissues of a root:
• Vascular tissues:
Xylem - water-conducting tissue, wood
Phloem - food-conducting tissue, bark.
• Endodermis - the inner layer of the cortex.
This selectively permeable layer filters
absorbed soil water passing into the cells to
the xylem.
• Cortex - serves as an area for food storage.
• Epidermis - a single layer of fatty cells serving
to protect the cells beneath.

24. Monocot stems have numerous vascular bundles scattered
throughout the stem.
xylem- located in the half of the bundle toward the
center of the stem
phloem - occurs in the half toward the outside surface
of the stem.
Each bundle is surrounded by a sheath of elongated, heavy-
walled sclerenchyma fiber cells, which provide mechanical
support for the stem.
Dicot stems have vascular bundles arranged in the form of a
cylinder, around a central core of parenchyma tissue called
the pith. The tissue outside the vascular bundles is called the
cortex. The outer edge of the cortex, just beneath the
epidermis, functions mainly in the mechanical support of the
stem.