Unit 5: Plant Organisms

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COMPARATIVE ADJECTIVES

după Arancha Alonso

Secondary 1 Geography Chapter 3

după Darius Neo Zhi Yu N/A

Plant reproduction

după Cheng Hong Jiun

Grade 3: Parts of a plant

după Umaima Motiwala

Unit 5: Plant Organisms

Plant Transportation

Transportation of Water/Nutrients

3. Transport into Leaves

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

2. Transport into Stem

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

1. Roots absorb nutrient/water

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

Transportation of Sugars

3. From phloem cells to sink cells

Water re-circulated into xylem

Passive transport: High concentration of sugar in phloem, low in sink

2. Through Pholem

Not Well Understood

Translocation moves sugars from phloem cell to phloem cell

1. Source to Pholem

Water moves from xylem to phloem when high concentration of sugar through osmosis

Active transport of sugars across cell membrane

About transportation

Sugars can move up/down (Nutrients moves only up)

Sink: Cells with low concentration of sugars

Source: Cells with high concentration of sugars

Vascular Cylinder

Phloem

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

Xylem

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

Reproduction

Sexual Reproduction

Pollen (male gamete) enters ovary (female gamete) and fertilizes into a seed

Asexual Reproduction

Cutting: part of plant falls off

Grafting: Combine several varieties of fruit

Runners: Drops new shoots into the ground and establishing new roots

Plant Body

Types of Plants

Dicotyledons (Dicots) (Oak trees, dandelions, canola)

Monocotyledons (Monocots) (Orchids, grass, lilies)

Flowers

Structure of Flower

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

Dicot: Multiples of 4 or 5 petals

Monocot: Multiples of 3 petals

Leaves

Types of leaves

Leaf Vein Structure

Monocots: Parallel, Leaf sheet

Dicots: Branching, Petiole

Leaf Shape

Gas exchange

Photosynthesis

Defense

Internal Structure

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

Seeds

Germination (Development of seed)

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

Conditions for Germination

Light: For photosynthesis

Oxygen: to carry out cellular respiration

Temperature: To activate enzymes

Moisture: After heavy rain

Seed Dispersal

Propelled by plant

Carried through wind/water

Fruit (through digestive tract)

Stick to Animals

Structure of Seed

Endosperm: Nutrient rich, food for embryo

Seed Coat: Tough coat for protection

Function:provides nutrients to embryo and becomes first leaf

Dicots: Two seeded leaf

Monocots: One seed leaf

Roots

Root Structure

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

Types of roots

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

Stems

Growth Rings

Summer Wood: thick walls, dark colour Xylem produced slowly

Spring wood: thin walls; light colour Xylem produced rapidly

Dicots V.S Monocots

Dicot: vascular bundles arranged in a ring (vascular cambium)

Monocot: vascular bundles scattered throughout stem

Types of Stems

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

Function

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

Types of Cell Tissue

Meristematic

Role: Plant growth; regions that are immature and continue to divide (meristems)

Lateral meristems or Cambium

Apical meristems (Tips of Roots/Shoots)

Dermal

Wxy cuticle

Thick Cell Walls

Outermost cell layers

Role: Protection

Epidermis and Dermis Cells

Vascular

Role: Transport of nutrients and support

Phloem: Thin cell walls, living at maturity

Xylem: Thick cell walls, dead at maturity

Ground

Role: Cellular growth, Storage, Support/Protection

Sclerenchyma = lignin in cell walls/dead

Collenchyma = thick walled/living

Parenchyma = thin walled/living

Plant Responses

Plant Adaptations

Salt: Roots lose water to soil through osmosis

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

Drought: Less water taken in than used

Response: Stomata in pits surrounded by hairs

Response: Thick cuticle and epidermis

Response: Modified leaves (spines/needles)

Response: Fleshy stem/leaves (holds water)

Flooding: Lack of oxygen for cellular respiration

Response: Partial roots above ground

Rapid Plant Movement

Increases/decreases turgor pressure of the mesophyll cells

Caused by movement of water/ions in/out of cells

Quickly Reversable

Rapid movement in response to stimulus

Tropisms

What is it

Regulated by plant hormones

Causes plant to bend to stimulus

Small Responses

Types of Tropisms

Thigmotropism: Growth of plant in response to touch

Geotropism: Growth of plant in response to gravity

Phototropism: Growth of plant in response to light