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.