Download basic horticulture – notes

BASIC HORTICULTURE – NOTES
WEEK #2
CELLS and TISSUES
PASS BACK GRADED ASSIGNMENT - LAB #1 – Exercise 2
BIOLOGY LAB SAFETY SHEETS – turn into me
LAB #1 – Exercise 3 – ARTIFICIAL CLASSIFICATION
DUE end of lab NEXT WEEK (go over terms in lab packet)
DIFFERENCES between SUNSET and USDA ZONES
 SUNSET - Climate Zones (Portland - Zone 6)

USDA -Temperature ranges only (Portland - Zone 8)

CLIMATE vs. WEATHER
 WEATHER - is what you see outside your window
 CLIMATE – looks at ALL WEATHER EFFECTS in your
area throughout the seasons
o DISTANCE from the EQUATOR - coldness and
daylight hours
o ELEVATION - higher up - means colder overall
and larger temperature swings
o PACIFIC OCEAN influence
 Nearer
 Milder winters
 Cooler summers
 Higher moisture and rainfall
 Farther – opposite
o CONTINENTAL AIR MASS
 Closer to the Rockies more influence - dryer
o LOCAL TERRAIN
 Hillsides – warmer
 Valleys – cold air drains into basin
o MICROCLIMATES – specific to site
Examples: hot south wall or near driveways collect heat during day and radiate heat at night
GLOBAL WARMING & ZONE SHIFTS
(show on computer/screen)
The USDA awarded a grant to the American Horticultural Society (AHS) to update the map of
plant hardiness zones, reflecting the average low temperatures across the country. AHS produced
a map based on 16 years of data (the previous map was based on 13 years of data) that shows how
warming climates have pushed the zones slightly northward. Three years later, the USDA has
failed to publish it. But, the Arbor Day Foundation has published a new map.
View the change at: http://www.arborday.org/media/zonechanges.cfm
REVIEW – Briefly review last weeks highlights
CELLS and TISSUES
CELLS – basic unit of all life and CYTOLOGY - Study of Cells
LOWER PLANTS – green algae
 Little variation in cell types
HIGHER PLANTS – especially VASCULAR PLANTS
 Cellular DIFFERENTIATION or SPECIALIZATION
 Exhibit DIVERSITY
o Size
o Form
o Function
 We see cells that…
o Make, store and transport FOOD
o Absorb and transport WATER
o Structural STRENGTH
o Produce HORMONES
o DIVIDE to form NEW cells
ORIGINATION OF CELLS AND CELL THEORY
ROBERT HOOKE (1665)
 DISCOVERED CELLS under microscope – cork cells
 Called “CELLA” for small room
 Cell wall of dead cork cells
SCHWANN and SCHLEIDEN (1838)
 Proposed CELL THEORY
o Cells are SMALLEST LIVING UNIT of all
organisms
o Still stands today
PARTS OF A CELL (show overhead and handout)
Despite VARIATION of cells in SIZE, FORM and FUNCTION,
ALL CELLS have some COMMON CHARACTERISTICS
CELL WALLS – VARY in THICKNESS
 THICKNESS DETERMINES HOW PERMEABLE it is,
how much it will allow the passage of water and chemicals
 Adds SHAPE and SUPPORT to cell
 PROTECTS the inner cell
o PRIMARY cell walls
 Thin membrane
 Elastic
 Permeable to water
 Made of CELLULOSE
o SECONDARY cell walls
 Inside primary wall
 Thicker
 Rigid and inelastic (cell growth stops)
 Supportive
 impermeable to water
 Made of LIGNIN
MIDDLE LAMELLA – layer between cells
 Cements cells together (like mortar for bricks)
 Made of PECTIN
o Extracted commercially for jams and jellies
CYTOPLASMIC MEMBRANE – cell membrane
 Inside cell walls
 Thin
 Semi-permeable
o Regulates what can pass through or not
o “GATEKEEPER” of the cell
CYTOPLASM – Cell sap or “GOO” that supports the organelles
 75 – 90 % water
 contains fats, proteins, carbohydrates that cell produces or
uses
 CYTOPLASMIC STREAMING – movement of
cytoplasm
PLASMODESMATA – interconnecting strands of cytoplasm
VACUOLE – large STORAGE SAC in middle of cell
 Up to 90% of cell volume
 Relatively impermeable membrane, requires active
transport (pumping to get materials inside)
 Contains WATER, NUTRIENTS and WASTE products
 Contains pigments – ANTHOCYANINS (red and blue)
 Provides support for cell – water content of vacuole
maintains rigidity or TURGIDITY
o Without turgidity of cell plant wilts
NUCLEUS - the “BRAIN” or “DIRECTOR” of cellular activity
 NUCLEAR MEMBRANE – ENVELOPE that holds
everything together
 NUCLEOLI– forms RIBOSOMES
 Contains CHROMOSOMES genetic information (DNA)
PLASTIDS – “BODIES” with a range of functions
 CHLOROPLASTS - contain CHLOROPHYLL
o Green pigment involved with PHOTOSYNTHESIS
( process of changing light energy, O2 & H20 into
sugars)
 CHROMOPLASTS – contain CAROTENOIDS
o Yellow or orange pigments – which give leaves,
flowers and fruit color
 LEUCOPLASTS – colorless organelles
o Synthesize and store fats, starches, & proteins
MITOCHONDRIA – “POWER PLANT” of the cell
 Breaks down sugars for ENERGY, CO2 and H2O release
 RESPIRATION process universal to all plants and
animals
ENDOPLASMIC RETICULUM – circulatory system of the cell
 Tubes and channels through cytoplasm
 TRANSPORTS materials from organelle to organelle, or
in and out of cells (through plasmodesmata)
RIBOSOMES
 Reside on endoplasmic reticulum or free in cytoplasm
 Function as PROTEIN and ENZYME production
LYSOSOMES – “suicide sac”
 Contains ENZYMES to DIGEST injured cell parts
 Defense mechanism against disease
TISSUES
CELLS do not usually work individually, they usually work with
others.
GROUPS of CELLS that perform a COMMON FUNCTION are
called TISSUES.
MERISTEMATIC TISSUE
 Undifferentiated cells undergoing ACTIVE GROWTH
o Multiplying by cell division
 MITOSIS
 prophase, metaphase, anaphase, telophase
o Elongation of cells - growth
TYPES of MERISTEMATIC TISSUE (Show overhead)
 APICAL MERISTEM
o Growth in LENGTH
o PRIMARY growth
o ROOT and SHOOT tips
 LATERAL MERISTEM
o Growth in WIDTH or GIRTH
o SECONDARY growth
o VASCULAR CAMBIUM
 DICOTS only – allows for growth in branches
and trunks
 MONOCOTS have no vascular cambium –
growth is limited to enlarging cells
 INTERCALARY MERISTEM – grasses (page 51)
o Base of grass leaf or above node
 Allows grasses to be cut and still grow back
PERMANENT TISSUES – Cells where GROWTH and
DIFFERENTIATION are COMPLETE
SIMPLE TISSUES - contain only ONE TYPE of cell
TYPES of SIMPLE TISSUES (see handout& overhead)
 PARENCHYMA
o Large ROUNDED, loosely packed cells
o PRIMARY cell wall – still elastic
o LIVING
o Function – PRODUCE & STORE FOOD
or compounds like nectar and latex
Example: pith, cortex
 COLLENCHYMA
o More differentiated cells, ELONGATED
o UNEVENLY THICKENED walls –
laying down cellulose
o Adding STRENGTH but still FLEXIBLE
o LIVING
o Function – SUPPORT for YOUNG
ORGANS leaves, stems, & roots
Example: rhubarb, celery ribs
 SCLERENCHYMA
o ELONGATED cells
o SECONDARY cell walls - thickest, most
RIGID cell walls composed of LIGNIN
o DEAD
o Function – CONDUCTION, SUPPORT
and PROTECTION
Example: FIBERS – thickened, but still
flexible – hemp, jute, & cotton
Example: SCLEREIDS – irregular
extremely thick walls in seed coats, nut
shells, pits of stone fruits (peach), pear
grains
COMPLEX TISSUES - formed with TWO or MORE
TYPES of cells
TYPES of COMPLEX TISSUES
 VASCULAR TISSUES – conductive tissues
o PHLOEM – conducts FOOD
 SUGAR produced in leaves “flows”
UP or DOWN to storage tissues in
stems and roots
 Consists of TWO CELL TYPES:
 SIEVE TUBES - elongated
cells with sieve plates on ends,
cytoplasm flows from cell to
cell, living with no nucleus
 COMPANION CELLS –
contains nucleus, controls
activity of both cells
o XYLEM – conducts WATER
 From roots UPWARD to leaves
 Adds SUPPORT
 Consists of TWO CELL TYPES:
 DEAD cells at maturity
 NO CYTOPLASM
 TRACHEIDS – long and
tapered with angled end-
plates, in more primitive
plants
 VESSELS – shorter, much
wider cells that lack endplates
 PITS to let water leak into
living cells nearby
 DERMAL TISSUES
o EPIDERMIS – skin tissue
 ONE CELL LAYER THICK
 Functions:
 PROTECTION from water
loss, heat, insects and diseases
 GAS EXCHANGE
 Consists of :
 GUARD CELLS &
STOMATA - openings on
bottom of leaf that regulates
gasses – O2, CO2, & H20
vapor
 TRICHOMES – outgrowths of
epidermal cells to form hairs
or glands
 CUTICLE – waxy layer on
epidermis for protection
o CORK and CORK CAMBIUM
 WOODY PLANTS the epidermis
sloughs off and is replaced by the
cork and cork cambium
 Function:
 PROTECTION from water,
insects and diseases
 Consists of:
 CLOSELY PACKED CELLS
for protection
 SUBERIN – fatty substance
that repels water
(NOTE: BARK consists of PHLOEM,
CORTEX, CORK and CORK CAMBIUM)
LAB – WEEK #2
The Microscope
Show light microscope and dissecting microscope
Go over how to carry and parts of microscope
Lenses and how to find things using the microscope
The Cell
Show how to prepare a slide
Show how to prepare cork, onion, elodea and protozoa
Show where prepared pollen grain slides are
Plant seeds?