Haploid (n)

One copy of genome

Gametophytes

Transpiration

Evaporation pulls up water through the stems.

Symplast

Moves within cells

Apoplast

Moves between cells

Plant Evolution

Aquatic Plants

Non-vascular

Avascular

Land Plants

Mainly vascular

Some avascular plants in moist conditions.

• Began in oceans (aquatic plants).
• Adaption to survive in dry environments (land plants).
• Developed vascular tissues (diversification).
• Pollination/seeds/woody structures (success/animal involvement).
• Flowers and fruits (diversification, co-evolve with animals).

Adaptions for Plants to Colonize Land

Adapt to Air

Structural support

Cell wall for growth

Cuticle, waxy coating

Stomata, guard cells, for gas exchange

Vasculature for water and nutrient transport.

Reproduction

Gametangia prevents gametes from drying

Embryos for young plants

New dispersal

Alternation of generations.

Survival

Pigments

Spores

Associations w/ fungi?

Aquatic Plants

All nonvascular.

Outgroup

Unicellular

Has peptidoglycan

Red Algae

Lacks chlorophyll B

Lacks starch storage

Has phycoerythrin pigments (red color).

Green Algae

Contains chlorophyll B

Has starch storage

Starch storage is unique to green algae/plants

Starch storage in stroma in chloroplasts.

Algae

Refers to all aquatic photosynthetic eukaryotes.

Colonial Multicellularity

Such as volvox.

SIngle cells to multicellular colonies w/ cell complexity = evolution.

Differentiated Cell/Tissue Multicellularity

Such as stoneworts

Stoneworts

Freshwater aquatic green algae

Not related with land plants (mosses).

Land Plants

Land Plants

Embryophytes (has protected embryos).

Mostly vascular, though some nonvascular.

• Nonvascular kinds (mosses, liverworts, hornworts) live in wet places, but not immersed in water.

Has alternation of generations (haploid <-> diploid).

Nonvascular Land Plants

• Circulation of water and minerals by diffusion.
• Gametophyte (n) (haploid) dominates.
• Sporophytes (2n) (diploid) dependent.
• Have rhizoids (no true roots)

Vascular Land Plants

• Has true roots
• Lignin provide rigid structure to grow tall
  • In cell walls
  • Height is good to intercept sunlight and disperse spores more efficiently.
• Have rhizomes.
  • An underground system of roots.
  • Mycorrhizomes are the root system of fungal plants.
• The diploid sporophyte stage dominates
• Does not depend on water to reproduce.
• Has true vasculature.
  • Tracheids (xylem) are dead cells that transport water/?
  • Phloem are living cells that transport sugars/?

Vasculature

Has complex fluid system.

Xylem vessel

Vessel cells?

"Roots to shoots"

Dead

One-way flow.

Phloem vessel?

Companion cells?

Sieve, tube-like cells

Live cells

Two-way flow.

Leaves

• 1st primitive leaf-like structures called 'microphylls'.
  • w/ branching structures 'megaphylls'.
  • overtopping growth form (net venation?)?

Vascular Leaves

Leafy greens = sporophytes

Smaller, dependent gametophytes inside flowers.

Nonvascular

Leafy green = gametophytes

Smaller, dependent sporophytes.

Seeds Plants

Gymnosperms

"Naked seed"

Reproduction via strobili (cones)

Cones are unisex

Conifers

Female cones & male cones (pollen) = sexual reproduction.

Female cones are higher to reduce chance of self-pollination

• To increase genetic diversity.

Angioperms

"Enclosed seed"

Flowering plants

Flowers are sexual organs

Fruits are seed protection and dispersal.

Ovule and seeds protected in a modified leaf called a carpel.

Ferns

Earliest land plants

Ferns are exceptions, they need water! Have flagellated sperm.

Ferns have spores, not seeds, clusters called sporangia.

Spore dispersal needs air like vascular plants.

Fertilization needs water like non-vascular plants.

Similar to both aquatic plants and land plants.

• More similar to land plants because they have true vasculature.

Plant Vasculature

Table 1: Phloem vs. Xylem

Transpiration-Cohesion-Tension Mechanism

For water control in plants, getting it to the leaves.

Transpiration and evaporation pulls water up through the stems.

Water evaporation + tension pulls up the water column against gravity.

Positive water pressure at ground level, negative water pressure higher up.

Pressure Flow Model for Phloem Sap Transport

Energy stored in 'sink' cells such as fruit, tubers, seeds.

Active transport of the sugar sucrose into concentrated areas require ATP energy.

• This creates the fruits, tubers, or seeds.

Source Cells

Phloem transports against the concentration gradient into the 'sink' cells.

Structure

• All vascular plants have stomata.
• All land plants have cuticles.

Cell Wall

Made of cellulose, lignin.

Cellulose is make of glucose

Lignin is a protein for the structure.

All land plants have a cell wall.

Stomata

Pores in cuticle help conserve H20.

Guard cells open and close these.

Waxy Cuticle

Conserves water

Water Conduction in Vascular Plants

Cohesion Surface tension

Interacts with other water molecules (attraction)

Adhesion

Water is attracted to other things that have dipoles (are polar molecules).

Energy Storage

Starch

Also made of glucose for energy in plants.

Long thin structure is hard to make available quickly.

Glycogen

Made of glucose for energy in animals.

Easier to snip off the ends since it's a branching pattern for quick energy release.

Roots

Root Hairs

Increase the surface area for uptake of water/minerals.

How water moves into plants?

Symplast

Movement through cell to cell regulated by plasmodesmata (proteins that create channels between cells).

Easier to regulate.

Apoplast

Movement of water between cells.

Less regulated.

Study Guide

Aquatic Plants

• 1st multicellular plants were in our freshwaters and marine waters
• Which group of Plantae is unicellular?
• What else makes Glaucophytes appear to be more “primitive”?
• What characteristic do all plants have in common, that distinguish them from Microbial Eukaryotes?
  • The only exception is the outgroup, Glaucophytes.
• What is a unique hallmark of each group of Aquatic plants presented:
  • Glaucophytes
  • Red Algae
  • Green plants
• Red algae thought question: think about the color of a thing. If you see the cardinal is red, then is it absorbing red light or not?
  • Remember photosynthesis requires absorption of certain wavelength of light that correspond to different energies of light.
  • If red is a long-wavelength, low-energy color, why are Red Algae are found in deep water?
• What characteristic do all GREEN plants in the Plantae have in common, that distinguish them from Glaucophytes & Red Algae.
• What is the basic building block of starch?
  • Where are starch granules stored in the plant cell?
  • What is the difference between amylose and pectin?
• Why is the classification of some green plants such as 'algae' complicated?
  • Why is “algae” not a particularly useful term in classifying plants.
• What is unique about the algae "sea lettuce" life cycle?
• Why is Volvox interesting?
  • How many cell types does it have ... what Microbial Eukaryote do some of those cells look like?.
• What group of aquatic plants is most similar to land plants?
  • What is apical branching growth? Do land plants grow this way?

LAND PLANTS

• a big evolutionary step!
• Why do we call land plants embryophytes?
• What type of lifecycle do LAND plants have?
• What abiotic conditions on land required aquatic lineages adapt & evolve, in order to survive on land?
• LAND plants can be NON-vascular or VASCULAR. What distinguishes non-vascular and vascular plants?
• Name some NON-vascular plants ... what types of cells/tissues do they use to circulate water & nutrients
• What is the structural part of land plant cells that provides cellular shape/support? What is it made out of?
• What role do stomata play in land plants - what three things are exchanged? Why regulate that?
• Why would land plants need a waxy cuticle?
• What are the two types of vascular tissue in VASCULAR land plants; know all the names, what they transport.
• What is the difference between Rhizoid, Rhizome, and Mycorrhizae?
• Cellulose is plant cell wall structure, but not as rigid as so is Lignin, why is Lignin so important for land plants?
• Note Land plants show Alternation of Generations:
  • What is a gametophyte, and what is a sporophyte (which is diploid, which is haploid)?
  • Which form dominates in most non-vascular plants, which dominates in most vascular plants?
• What’s the difference in life cycle, when comparing Non-Vascular to Vascular plants?
• Vascular vs. non-vascular plant: which one needs a moist/wet habitat for reproduction?
• List some differences between Non-Vascular land plants and Aquatic plants.
• List some main differences on LAND: Non-Vascular vs. Vascular plants
• How is a fern representative of a snapshot in evolution, between NON-vascular and vascular plants?
• What are the main two cell types in xylem?
• What are the main two cell types in phloem?
• Xylem and phloem: Which are live, which are dead?
• Which are tube-like, to transport water & minerals, what direction?
• What two forces on water determine its path through a plant?
• What two forces determine sugar pathways in plants?
• Which tissues transport sugar? What direction?
• What is actively transported, needing energy, what is passively transported
• What synapomorphies are unique to Gymnosperms? There are two example plants in the slides – know!
  • How do they reproduce, what are their seeds like?
  • Are they fully developed in vasculature?
• What synapomorphies are unique to Angiosperms?
  • What structures do they have that other vascular land plants do not?
• What is a carpel? Is it found in Gynmosperms?
• How are roots different than rhizoids (Ch. 20)?
• From what structure did true leaves likely evolve?
• Why is water such a special molecule?
  • What is a dipole, what is cohesion, and how is it different than adhesion? know all three.
• Understand the Transpiration-Cohesion-Tension model of water transport.
• What three molecules quickly travel in/out of stomata?
• What is a root hair; what is the purpose of a root hair?
• What are 2 ways water moves from soil to Xylem via root hairs?
• What are the two ways the water moves into plants? Which is regulated?
• Where are the xylem and phloem cells situated in a root, why are they next to each other?
• What is negative pressure; what drives it, does it require energy?
• What is positive pressure; what drives it, does it require energy?
• What is a sink cell? Examples? What does it store?
• What is turgor pressure?