12b plant systems

Plant

Systems:
Structures

and Transport

Functions

Exploring the Root and
Shoot Systems of Plants

This Photo by Unknown Author is licensed under CC BY

Lesson

Objective

- Understand how plant
structures facilitate the
transport of water,
minerals, and sugars.

- Learn the roles of
xylem and phloem in
plant transport.

Multiple Choice

Photosynthesis causes plants to

• produce sugars and oxygen

• collect water and waste

• use up sugars

• create carbon dioxide

Multiple Choice

How does water move through plants?

• It goes out through the roots.

• It enters through the stomata.

• It gets trapped in the membrane.

• It is carried through the xylem

Root System

•Key Features:

•- Functions:

•

- Anchors the plant.

•

- Absorbs water and minerals.

•

- Stores sugars.

•- Types of Roots:

•

- Taproot: Dominant central
root.

•

- Fibrous roots: Thin, branching
roots.

•

- Root hairs: Increase surface
area for absorption.

Multiple Choice

___________ plants have roots that helps them absorb water and anchor them to the soil.

• vascular

• non-vascular

• mossy

Multiple Choice

Water enters the roots thanks to a PROCESS called ___________. Water enters THROUGH the ________________.

• osmosis, cell wall

• osmosis, cell membrane

• active transport, cell membrane

• active transport, cell wall

Xylem

•Xylem: type of vascular tissue in plants that is responsible for
transporting water and dissolved minerals from the roots to the
rest of the plant.

•Key Features of Xylem:

•Composition: Made up of specialized cells like tracheid and vessel
elements, which are dead at maturity and form hollow tubes.

•Direction of Flow: Transports water and minerals upward from
roots to leaves.

•Additional Role: Provides structural support due to the presence
of lignin, a rigid compound in its cell walls.

This Photo by Unknown Author is licensed under CC BY-SA-NC

Multiple Choice

The tubes that carry water and nutrients are called

• xylem

• phloem

• stems

• roots

Open Ended

What is Xylem?

Multiple Choice

Set of tubes that carry food throughout the plant

• xylem

• phloem

• stems

• roots

Multiple Choice

Photosynthesis happens in the leaves of plants and requires

• sunlight, oxygen, and carbon dioxide

• sunlight, water, and carbon dioxide

• oxygen and carbon dioxide

• oxygen and sunlight

Phloem

•Key Features of Phloem:

•Function: Transports sugars (mainly
sucrose) and other organic molecules
from the leaves (source) to other parts
of the plant (sink).

•Direction of Flow: Bidirectional,
depending on the plant's needs:

•From leaves to roots, flowers,
fruits, or storage organs.

•From storage organs to growing
parts during periods of low
photosynthesis.

Phloem: vascular tissue in plants responsible for transporting sugars, nutrients, and other organic compounds throughout the plant

Multiple Choice

Tiny openings in the leaves of plants where gases (oxygen and carbon dioxide) are exchanged.

• xylems

• phloems

• stomata

• junctions

Multiple Choice

What is phloem?

• Storage for sugar and other nutrients

• Transportation of nutrients and Sugars

• IDK

• Creates Antibodies

Multiple Choice

Stomata open and close to helps the plant lose water. This process is called

• evaporation

• transpiration

• condensation

• sublimation

Shoot
System

•Key Components:

•- Stems: Transport
water and sugars
through xylem and
phloem.

•- Leaves:

•

- Photosynthesis site.

•

- Gas exchange
through stomata.

Multiple Choice

Where are xylem and phloem found?

• in the roots

• in the stem

• in the leaves

• in the soil

Transport
in Plants

•Water Movement:

•- Pathway: Root → Stem
→ Leaf → Exit through
stomata.

•- Processes Involved:

•

- Osmosis: Water
enters roots.

•

- Transpiration: Water
vapor exits via stomata.

Turgor Pressure

•Definition: Pressure exerted by
water on cell walls.

•How Turgor Pressure Works:

1.Water Uptake:

1. Water enters plant cells by

osmosis due to higher solute
concentration inside the cell
compared to its surroundings.

2.Vacuole Role:

1. The central vacuole fills with

water, increasing its volume.

3.Pressure Against the Cell Wall:

1. As the vacuole expands, it

pushes the plasma membrane
outward against the rigid cell
wall, creating turgor pressure.

Multiple Choice

What is Turgor Pressure ?​

• Pressure exerted by water on cell walls
• Amino acids of the plant

• Creates storage vessels for the plant to use for nutrients

• Pressure exerted by the stroma

Explanation Slide...

Pressure exerted by water on cell walls

Importance of Turgor Pressure:

•Structural Support:
•High turgor pressure keeps plants upright and leaves firm.
•Low turgor pressure causes wilting.
•Cell Expansion:
•Drives cell elongation during growth.
•Stomatal Function:
•Turgor pressure in guard cells regulates the opening and
closing of stomata for gas exchange and transpiration.

•High pressure – plant erect
•Low pressure – plant wilts

This Photo by Unknown Author is
licensed under CC BY

Transpiration

•Definition: Water vapor diffuses
through stomata in leaves.

•Steps in Transpiration:

1.Water Absorption:

1. Water is absorbed by the

roots from the soil.

2.Water Movement:

1. Water travels upward through

the xylem to the leaves,
driven by transpiration pull,
cohesion, and adhesion.

3.Evaporation:

1. Water evaporates from the

surface of mesophyll cells
inside the leaf into the air
spaces.

4.Diffusion:

1. Water vapor diffuses out of

the leaf through the stomata
into the atmosphere.

Multiple Choice

What is Transcription?

• Water Storage in the Roots

• Dissolved water vaper

• Water movement through out the plant

• Guard Cells

Importance of Transpiration:

Creates a transpiration pull that draws water and nutrients from roots to
shoots.

Water

Transport:

Cools the plant by evaporative cooling, especially in hot environments.
Cooling

Mechanism:

Facilitates the exchange of gases needed for photosynthesis and respiration.

Gas Exchange:

Helps maintain cell structure and function.

Maintains

Turgor

Pressure:

Summary
of Day 1

•Key Takeaways:

•- Root system absorbs water and minerals.

•- Shoot system transports materials and
supports photosynthesis.

•- Xylem moves water; phloem moves
sugars.

•- Transpiration and turgor pressure
maintain plant health.

Exit Ticket

Multiple Choice

What is the answer to the exit ticket?

• A

• B

• C

• D

Plant Systems and Interactions

Overview of Plant Reproduction

Key Points:

• Plants reproduce both sexually and asexually.

• Sexual reproduction involves flowers and the fusion of gametes.

• Asexual reproduction produces genetically identical offspring.

​

• Plants reproduce sexually through flowers, which contain male and female reproductive organs.

• Stamen (Anther + Filament).

• Carpel (Stigma + Style + Ovary).

• Seeds: Result of fertilized ovules.

• Fruit: Ripened ovary aiding seed dispersal.

​Sexual Reproduction

​

• Produces and releases pollen grains, which contain male gametes (sperm).

• Pollen grains have a tough coat to protect the sperm during transfer to the female structures.

​​Anther

​A stalk that supports the anther, positioning it for effective pollen transfer by wind, insects, or animals.

​​Filament

​Male Reproductive Parts

​

• The sticky surface at the top of the carpel where pollen grains land during pollination.

• Specialized to capture and germinate compatible pollen grains.

​​Stigma

​

• A tube-like structure that connects the stigma to the ovary.

• Guides the pollen tube to the ovule for fertilization.

​​Style

​

• Contains ovules, which house the female gametes (eggs).

• After fertilization, the ovary develops into a fruit.

​​Ovary

​Female Reproductive Parts

Multiple Choice

What's the purpose of the Stigma?

• A storage unit to hold all egg cells

• Tube like structure that connects to the ovary

• Capture pollen grains

• Located inside the Ovary

​Embryo: The young plant that will develop into the mature plant after germination.

Cotyledons: Store nutrients that support the embryo during germination.

Seed Coat: Protects the seed from physical damage and prevents water loss.

Seeds

​

• Protects the developing seeds.

• Facilitates seed dispersal through mechanisms like being eaten by animals, floating in water, or carried by the wind.

​​Fruits

Multiple Choice

What is a seed coat?

• Protection from Harm

• Water Repellant

• Outer layer of an Ovary

• Embryo Sac

Explanation Slide...

Protects the seed from physical damage and water damage

​Seed Dispersal Methods:

• Wind (e.g., dandelions).

• Water (e.g., coconuts).

• Animals (e.g., berries).

• Explosions (e.g., peas).

• Gravity (e.g., apples).

​Seed Dispersal

• Self-Pollination: Occurs when pollen from the same plant fertilizes its ovules.

• Cross-Pollination: Involves pollen transfer between different plants, increasing genetic diversity.

​

​Pollination

• A pollen tube grows from the pollen grain down the style to the ovary.

• Sperm cells travel through the tube to fertilize the ovule, forming a zygote.

​Fertilization

Multiple Select

What Insects are Pollinators?

• Butterflies

• Bees

• Beetles

• Roaches

​Key Points:
Asexual Reproduction: produces plants that are genetically identical to the parent plant

• Methods:

  • Roots: Tuberous roots (e.g., sweet potatoes).

  • Stems: Stolons, runners, bulbs (e.g., strawberries, onions).

  • Leaves: Vegetative propagation (e.g., Bryophyllum).

• Advantages: Faster reproduction; stable environments.

• Disadvantages: No genetic variation.
  

​Asexual Reproduction

Exit Ticket

​What are the main differences between sexual and asexual reproduction in plants? Provide one example of each.

Tropisms and Plant Responses

What are Tropisms?
Tropisms: Directional growth responses of plants toward or away from environmental stimuli.

Significance: These responses enable plants to adapt to their surroundings, ensuring survival, reproduction, and resource acquisition.

​Tropisms

​

• Example: Roots grow downward into the soil.

• Function: Helps anchor the plant and absorb water and nutrients from the soil.

​​Positive Geotropism

• Example: Stems grow upward, away from gravity.

• Function: Maximizes access to sunlight for photosynthesis.

Negative Geotropism

​

• Plant cells detect gravity through organelles called statoliths.

• Hormones like auxin redistribute in response to gravity, promoting growth in specific directions.

​​Mechanism

​Geotropism (Gravitropism)

​Geotropism: Growth response to gravity

​Example: Stems and leaves bend toward light.

Function: Maximizes photosynthesis by exposing leaves to optimal light.

​​Positive Phototropism

​

• Auxins accumulate on the shaded side of the plant.

• Cells on the shaded side elongate, causing the plant to bend toward the light source.

​​Mechanism

​Phototropism: Growth response to light

Open Ended

What is Geotropism?

Explanation Slide...

Growth response to gravity

​

• Helps climbing plants secure themselves for better access to light.

• Protects certain plants by allowing them to retract or curl when touched (e.g., tendrils).

Function

​Contact with an object triggers rapid growth on the opposite side, causing the plant to bend or wrap around the object.

​​Mechanism

• Vines wrapping around a trellis or support structure.

• Sensitive plants reacting to physical touch.

​​Examples

​Thigmotropism

​Growth response to touch or physical contact.

Multiple Choice

What is phototropism?

• Growth response to light

• A mechanism of photosynthesis

• Growth response to gravity

• Growth response to touch

​

• Example: Roots grow toward areas of higher moisture.

• Function: Ensures plants access water, crucial for photosynthesis and nutrient transport.

​​Positive Hydrotropism

​

• Root tips detect water gradients in the soil.

• Cells on the side of the root facing less water elongate, bending the root toward the water source.

​​Mechanism

​Hydrotropism

​Growth response to water.

​​Function

​Triggered by changes in turgor pressure within specialized cells.

​​Mechanism

​

• Venus Flytrap: Closes rapidly when prey touches its sensitive hairs.

• Mimosa Plant: Folds its leaves when touched or shaken.

​​Examples

​Nastic Movements

​Non-directional responses to stimuli, unlike tropisms, which are directional.

​Protects plants from herbivores or environmental stress.
Helps trap prey (in carnivorous plants) for nutrient acquisition.

Real-World Applications of Tropisms

• Phototropism: Greenhouses use light sources to optimize plant growth.

• Geotropism: Ensures proper orientation of roots and stems during early growth.

• Thigmotropism: Used in agriculture to grow climbing crops like beans and grapes efficiently.

• Hydrotropism: Studied for improving drought-resistant crops.

Multiple Choice

Name the 4 types of tropism

• Phototropism, Geotropism, Thigmotropism, Hydrotropism

• Lysotropism, Geotropism,Thermotropism

• Phototropism, Gigatropism,Hydrotropism,Geotropism

• IDK

​Exit Ticket

​Explain one way phototropism and geotropism work together to ensure a plant's survival

Explanation Slide...

produces plants that are genetically identical to the parent plant