arabera Alexander Boldis 4 years ago
584
Honelako gehiago
Leaves are main driving force of xylem upward
Transpiration
Factors Affect Transpiration
Number of Stomata per Leaf Surface Area: More stomata = Higher transpiration rate
Wind – High transpiration rate in high winds
Humidity: High transpiration rate in low humidity
Light: High transpiration rate during day since stomoa is open
Temperature: High transpiration rate in high temperature
Evaporation of water through the stomata of plant leaves
Xylem sap rises due to root pressure and capillary action
Capillary Action: Water rise because of attractive forces between water molecules and side of wall
Root pressure: Osmotic force pushes xylem sap upward
Water molecules and dissolved nutrients called xylem sap
Nutrients (Active Transport)
From low concentration (outside cell) to higher concentration (inside cell)
Water (Osmosis)
Water moves to vascular cylinder
Cytoplasm has less water than soil
Root Hairs
Form symbiotic association with fungi (mycorrhizae)
Increase SA to absorb more nutrients/water
Water re-circulated into xylem
Passive transport: High concentration of sugar in phloem, low in sink
Not Well Understood
Translocation moves sugars from phloem cell to phloem cell
Water moves from xylem to phloem when high concentration of sugar through osmosis
Active transport of sugars across cell membrane
Sugars can move up/down (Nutrients moves only up)
Sink: Cells with low concentration of sugars
Source: Cells with high concentration of sugars
Sieve tubes
Companion cells that direct activities and supply nutrients
Between are sieve plates (large pores to facilitate transport)
Long, hollow tubes
Transports sugar through the plant
Living Tissue
Types of Xylem
Vessel Elements:long, wide; joined together; more efficient
Trachiod: Long,Narrow; Trapid at ends
What is it?
Long, hollow tubes formed by non-living cells
Transports water/minerals from roots to stem/leaves
Pistil: Female Reproductive Organ
Ovary:Contains ovule (female gamete)
Stigma: Sticky tip to collect pollen grain
Stamen: Male Reproductive Organ
Anther: Produces pollen grain (Male Gametes)
Filament:Connects Anther to flower
Petals: Colourful to attract pollinators
Sepals:Covers and protect flower buds before blossom opens
Leaf Vein Structure
Monocots: Parallel, Leaf sheet
Dicots: Branching, Petiole
Leaf Shape
Gas exchange
Photosynthesis
Defense
Guard cells: control opening and closing of stoma
Stoma:gas passes in or out
Mesophyll cells (middle): contain chloroplast
Spongy: loosely packed, loosely packed for gas exchange, bottom layer
Paliasids:closely packed, upper layer
Epidermal cells (outside): covered in waxy cuticle
Dormancy – resting period
Absorption of water by the seed
Embryo releases growth hormone
Triggers cotyledons to convert starch to maltose
Maltose is used for cellular respiration
Sugar content is increased, causing more water to be absorbed
Seed coat softens and embryo emerges
Light: For photosynthesis
Oxygen: to carry out cellular respiration
Temperature: To activate enzymes
Moisture: After heavy rain
Propelled by plant
Carried through wind/water
Fruit (through digestive tract)
Stick to Animals
Endosperm: Nutrient rich, food for embryo
Seed Coat: Tough coat for protection
Vascular cylinder: Contains plants conducting tissues (xylem and phloem)
Dicot Vascular Cylinder V.S Monocot Vascular Cylinder
Endodermis: Wax layer;Separates cortex and vascular cylinder
Root Hairs: Increase SA to absorb more nutrients
Epidermis: Middle cell layer, Stores starch
Epidermis: Outer layer, Protects inside/absorb nutrients
Taproots: Found in dicots One thick, long, primary root in the middle Secondary roots branch from it
Fibrous Roots: Found in monocot Roots of equal size extend laterally over an area
Transport water/nutrients to stem
Some Store Food
Absorb Water/Nutrients
Anchor Plant
Summer Wood: thick walls, dark colour Xylem produced slowly
Spring wood: thin walls; light colour Xylem produced rapidly
Dicot: vascular bundles arranged in a ring (vascular cambium)
Monocot: vascular bundles scattered throughout stem
Woody: Hard/tough (wood); last winter
Woody System: Dicots
Bark: Everything outside Vascular cambium (protection)
Heartwood: Olderer Xylem (support)
Sapwood: Younger Xylem (transport)
Vascular cambium: Allows for thicker stem growth
Herbaceous: Green/soft; don't last winter
Specialized stems
"On Ground": Grow along soil
Bulbs: Tiny, underground stems
Tubers: Underground stems
Rhizomes: store wate/food to help survive winter
Raise/support leaves/reproductive organs
Transportation of nutrients/oxygen
Halophytes Response: Pump salt to stems at tip of plant; sheds tips to remove salt
Halophytes Response: Specialized glands pump salt across leaf epidermis for rain to wash away
Response: Stomata in pits surrounded by hairs
Response: Thick cuticle and epidermis
Response: Modified leaves (spines/needles)
Response: Fleshy stem/leaves (holds water)
Response: Partial roots above ground
Regulated by plant hormones
Causes plant to bend to stimulus
Small Responses
Thigmotropism: Growth of plant in response to touch
Geotropism: Growth of plant in response to gravity
Phototropism: Growth of plant in response to light