E

Plants and Fungi Study Guide Notes

Closest Relatives of Land Plants

  • Charophytes are the closest relatives of land plants.

Key Traits of Plants in Algae

  • Chloroplasts with chlorophyll a and b.
  • Cell walls made of cellulose.
  • Multicellular, eukaryotic, autotrophic organisms.

Unique Plant Traits Shared with Charophytes

  • Cellulose-synthesizing membrane proteins arranged in rings.
  • Structure of flagellated sperm.
  • Sequence similarities in nuclear, chloroplast, and mitochondrial DNA.
  • Formation of phragmoplast during cell division.

Key Traits of Nearly All Plants Not Found in Algae

  1. Alternation of Generations
    • Cycle between sporophytes (diploid) and gametophytes (haploid), with each alternating in dominance.
  2. Walled Spores Produced in Sporangia
    • Haploid spores grow into gametophytes through mitosis.
  3. Apical Meristems
    • Regions of growth at roots and shoots that increase exposure to light, CO₂, and nutrients; protect growing tips of roots.
  4. Multicellular, Dependent Embryos
    • Embryos develop from zygotes retained within female gametophyte tissues.
  5. Multicellular Gametangia
    • Archegonia: Female gametangia producing a single non-motile egg.
    • Antheridia: Male gametangia producing motile sperm that swim to fertilize the egg.
  6. Cuticle
    • A waxy epidermal covering that reduces moisture loss.
  7. Stomata
    • Pores for gas exchange between air and plant tissues.
  8. Symbiosis with Fungi
    • Plants and root-associated fungi exchange nutrients and aid absorption of minerals.

Bryophyte Classification

  • Phyla and Common Names:
    • Hepatophyta – Liverworts
    • Bryophyta – Mosses
    • Anthocerophyta – Hornworts

Bryophyte Life Cycle

  • Gametophytes:
    • Spores germinate into a protonema (one-cell thick).
    • Develop gametophore (moss body) attached to rhizoids for anchorage and nutrient absorption.
  • Sporophytes:
    • Develop from archegonia with structures: foot, seta, and sporangium (capsule).
  • Dominant Generation: Gametophyte.
  • Sperm Fertilization: Flagellated sperm swim through water to fertilize eggs in archegonia.

Vascular Plant Characteristics

  1. Dominant Sporophyte Generation
  2. Vascular Tissues:
    • Xylem: Transports water/nutrients.
    • Phloem: Transports sugars.
  3. Developed Roots and Leaves
  4. Sporophylls: Specialized leaves bearing spores.

Vascular Plant Life Cycle

  • Gametophytes: Smaller and underground.
  • Sporophytes: Above ground, derive from gametophytes.
  • Dominant Generation: Sporophytes.
  • Reproductive Structures:
    • Antheridia (male) produces sperm.
    • Archegonia (female) contains the ovary.

Leaf Types in Vascular Plants

  • Microphylls: Small leaves, single vein.
  • Megaphylls: Larger leaves with a branched vascular system.

Homosporous vs Heterosporous Plants

  • Homosporous: One type of spore and sporophyll.
  • Heterosporous: Creates both megaspores (female) and microspores (male).

Clades of Vascular Plants

  1. Lycophyta
    • Includes club mosses, spike mosses, quillworts.
  2. Monilophyta
    • Includes ferns, horsetails, whisk ferns; thrive in various climates.

Fungi Nutrient Acquisition

  • Digest food externally by secreting enzymes.

Definitions

  • Hyphae: Thread-like structures making up fungi, allowing nutrient absorption.
  • Mycelium: Network of hyphae anchoring fungi and aiding digestion.

Mycorrhizal Fungi

  • Enhances nutrient absorption for plants; plants provide sugars to the fungus.

Phyla of Fungi

  • Chytrids: Flagellated spores, cause amphibian declines.
  • Zygomycetes: Molds that affect fruits and vegetables.
  • Glomeromycetes: Create arbuscular mycorrhizae with plant roots.
  • Basidiomycetes: Includes mushrooms and plant parasites.
  • Ascomycetes: Sac fungi, producing spores in asci.

Components of Seeds

  • Embryo, Seed Coat, Food Supply.

Adaptations of Seeds

  • Protective outer layers ensure survival in adverse conditions.

Roles of Sporophytes and Gametophytes in Seed Plants

  • Dominant generation is sporophyte.
  • Gametes are produced within gametophytes which rely on sporophytes for sustenance.

Angiosperms and Gymnosperms

Gymnosperm Life Cycle

  • Microsporocytes create pollen grains that develop into male gametophytes. Pollen tubes deliver sperm to ovules.

Angiosperms

  • Key Adaptations: Flowers and fruits.

Flower Structures

  • Sepals, Petals, Stamens, Carpels define the reproductive parts of flowers.

Symmetry in Flowers

  • Radial Symmetry: Symmetrical from multiple angles.
  • Bilateral Symmetry: Symmetrical from one angle.

Fruit Development

  • Ovarian wall thickening around developing seeds forms the fruit.

Pollination Types

  • Self-pollination: Plant fertilizes itself.
  • Cross-pollination: Fertilization from different individuals.

Dicots vs Monocots

  • Dicots: Two cotyledons, netlike veins.
  • Monocots: One cotyledon, parallel veins.

Plant Cells and Structures

  • Define cell wall components, types of plant cells including parenchyma, collenchyma, sclerenchyma, and vascular tissues (xylem and phloem).

Plant Growth

  • Determinate Growth: Growth ceases at maturity.
  • Indeterminate Growth: Continuous growth throughout life.
  • Meristems enable growth; differentiation into mature cells allows for specialized functions.

Water Movement in Plants

  • Understand transport mechanisms: transpiration, bulk flow, and effects of pressure and solute potential.

Circadian Rhythms and Plant Responses

  • Plants can exhibit phenotypic changes based on diurnal light cycles, influencing functions like stomatal opening.

Plant Defenses

  • Against herbivory: Thorns, toxins.
  • Against pathogens: Bark, dermises.