E

Plant and Fungi Study Guide Chapters 29-39

Closest Relatives of Land Plants

  • Charophytes: Closest relatives of land plants.

Key Traits in Algae and Plants

  • Shared traits with algae:
    • Chloroplasts with chlorophyll a and b
    • Cell walls made of cellulose
    • Multicellular, eukaryotic, autotrophs
  • Unique traits shared only with charophytes:
    • Cellulose-synthesizing membrane proteins in rings
    • Structure of flagellated sperm
    • Sequence similarities in nuclear, chloroplast, and mitochondrial DNA
    • Formation of phragmoplast

Key Traits of Nearly All Plants (Not in Algae)

  1. Alternation of Generations:
    • Two types: sporophytes and gametophytes alternate in dominance.
  2. Walled Spores in Sporangia:
    • Haploid reproductive cells that grow into gametophytes via mitosis.
  3. Apical Meristems:
    • Growth sites for roots and shoots, increasing plant exposure to light and nutrients.
  4. Multicellular, Dependent Embryos:
    • Develop from zygotes retained within the female gametophyte.
  5. Multicellular Gametangia:
    • Archegonia (female) produces non-motile eggs, Antheridia (male) produces flagellated sperm.
  6. Cuticle:
    • Waxy covering reducing water loss.
  7. Stomata:
    • Pores for gas exchange.
  8. Symbiosis with Fungi:
    • Fungi colonizing roots, enhancing nutrient absorption and providing sugars.

Bryophyte Classification

  • Phyla:
    • Hepatophyta: Liverworts
    • Bryophyta: Mosses
    • Anthocerophyta: Hornworts

Bryophyte Life Cycle

  • Gametophytes:
    • Spores develop into protonema, then into gametophytes with gametangia.
  • Sporophytes:
    • May consist of foot, seta, and sporangium (capsule) discharging spores.
  • Dominance: Gametophyte generation is dominant.
  • Fertilization: Flagellated sperm swim in water to fertilize eggs in archegonia.

Vascular Plants

Tissue and Characteristics

  • Lignified Vascular Tissue: Allows for tall growth.
  • Traits of Vascular Plants:
    • Dominant sporophyte life cycles
    • Vascular tissues: xylem (water transport) and phloem (sugar transport)
    • Well-developed roots and leaves
    • Sporophylls (spore-bearing leaves)

Vascular Plant Life Cycle

  • Gametophytes: Small and underground.
  • Sporophytes: Above ground, dominating.
  • Non-reproductive structures: Antheridia (male) and archegonia (female).

Types of Vascular Tissue

  1. Xylem: Transports water/nutrients from roots.
  2. Phloem: Transports sugars from leaves to roots.

Plant Organs

  • Roots: Anchor and absorb water/nutrients.
  • Leaves: Increase light capture and photosynthesis.

Leaf Types

  1. Microphylls: Small leaves with a single vein.
  2. Megaphylls: Larger leaves with a branched vascular system.

Plant Reproductive Strategies

  • Homosporous: One sporophyll and sporangium.
  • Heterosporous: Produces megaspores (female) and microspores (male).

Clades of Vascular Plants

  • Lycophyta: Includes club mosses, spike mosses, and quillworts.
  • Monilophyta: Includes ferns and horsetails; diverse in tropics and temperate forests.

Fungi Characteristics

  1. Nutrient Acquisition: Secretes enzymes for external digestion.
  2. Hyphae: Filamentous structures making up mycelium.
  3. Mycelium: Functions as the root system of fungi.

Mycorrhizal Fungi

  • Symbiosis: Benefits both fungi and plants; fungi assist in nutrient absorption.

Phyla of Fungi

  • Chytrids: Flagellated spores, found in water bodies.
  • Zygomycetes: Rapidly-growing molds affecting fruits.
  • Glomeromycetes: Forms arbuscular mycorrhizae.
  • Basidiomycetes: Club fungi, significant decomposers.
  • Ascomycetes: Sac fungi, diverse habitats.

Seed Components and Survival Adaptations

  • Components: Embryo, seed coat, food supply.
  • Adaptations: Protective outer layer for dormancy.

Seed Plant Generations

  • Sporophyte Dominance: Dominant generation releasing pollen for fertilization.

Reproductive Structures in Seed Plants

  • Sporophylls: Megasporophylls (female) produce megaspores; microsporophylls (male) produce microspores.
  • Components of Ovule: Megasporangium, megaspore, and integuments.

Pollen and Fertilization

  • Pollen grains develop in microsporophylls, transferred by wind or animals to female gametophyte.
  • Gymnosphere Life Cycle: Involving microsporocytes, pollen grain formation, and dormancy.

Major Gymnosperm Phyla

  • Cycadophyta: Large cones, palm-like.
  • Ginkgophyta: One species, urban survivor.
  • Gnetophyta: Thrive in harsh climates.
  • Coniferophyta: Largest gymnosperm phylum, evergreen species.

Angiosperms - Flowering Plants

  • Phylum: Anthophyta
  • Reproductive Adaptations: Flowers and fruits
  • Flower Role: Attracts pollinators.

Flower Structure

  • Modified Leaves: Sepals, Petals, Stamens, Carpels
  • Stamen Components: Filament (supports anther) and Anther (produces pollen).
  • Carpel Components: Ovary (base), Style (connects ovaries to stigma), Stigma (receives pollen).

Fruit and Seed Dispersal

  • Fruits develop from ovary wall thickening and can attract animals for dispersal.
  • Cotyledons: Seed leaves crucial for seedling development.

Differences Between Monocots and Dicots

  • Monocots: One cotyledon, parallel veins, scattered vascular tissue.
  • Dicots: Two cotyledons, netlike veins, vascular tissue arranged in rings.

Plant Cell Structures

  1. Primary Cell Wall: Thin and flexible.
  2. Middle Lamella: Between primary walls.
  3. Plasmodesmata: Channels for cell communication.

Tissue Systems

  • Dermal, Vascular, and Ground Tissues.

Growth and Meristems

  • Primary Growth: Lengthening at apical meristems.
  • Secondary Growth: Thickness through lateral meristems.

Plant Responses and Hormones

  • Phototropism: Response to light.
  • Hormones: Auxins promote growth, Cytokinins promote cell division, Gibberellins affect seed germination.
  • Defenses: Toxins, thorns, and recruitment of predators to deter herbivores.

Nutrient Management

  • Macronutrients needed in larger amounts (e.g., Carbon, Oxygen).
  • Micronutrients needed in smaller amounts (e.g., Iron, Zinc).

Physiological Responses

  • Stomata control water loss and gas exchange.
  • Adaptations for drought and nutrient absorption vary among species.