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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?