Chapter 32: Plant Reproduction Flashcards
What are the four whorls of a flower, and what structures do they form?
Sepals (calyx): Protect the bud.
Petals (corolla): Attract pollinators.
Stamens (male): Anther (pollen sacs) + filament.
Carpels (female): Stigma (pollen reception), style, ovary (contains ovules).
Compare perfect vs. imperfect flowers.
Perfect: Contains both stamens and carpels (e.g., roses).
Imperfect: Only male (staminate) or female (carpellate) structures (e.g., squash).
What is the difference between monoecious and dioecious plants?
Monoecious: Male and female flowers on the same plant (e.g., corn).
Dioecious: Male and female flowers on separate plants (e.g., holly).
Describe the development of male and female gametophytes in angiosperms.
Male (pollen): Microspores form in anthers → mature into pollen grains (2 cells: tube cell + generative cell).
Female (embryo sac): Megaspores form in ovules → 7-celled, 8-nucleate structure (includes egg cell + central cell).
What are the three types of pollination, and give examples?
Abiotic: Wind (e.g., grasses) or water (e.g., seagrasses).
Biotic: Animals (e.g., bees, birds, bats).
Self-pollination: Pollen transferred to same flower/plant.
Explain double fertilization in angiosperms.
Sperm 1 + egg → diploid zygote (develops into embryo).
Sperm 2 + two polar nuclei → triploid endosperm (nutrient storage).
How do plants prevent self-fertilization?
Self-incompatibility: Biochemical recognition blocks pollen tube growth (e.g., Brassica species).
Dichogamy: Temporal separation of male/female maturity.
What is the role of the pollen tube?
Grows from stigma to ovule, delivering sperm cells to the embryo sac.
Define vegetative reproduction and provide examples.
Asexual reproduction via plant parts (no seeds):
Runners (stolons): Strawberries.
Rhizomes: Ginger, bamboo.
Bulbs: Onions.
What is apomixis, and how does it differ from typical asexual reproduction?
Apomixis: Production of seeds without fertilization (embryo forms from diploid cells).
Common in dandelions and citrus.
Compare advantages of asexual vs. sexual reproduction in plants.
Asexual: Rapid colonization, preserves successful genotypes.
Sexual: Genetic diversity, adaptation to changing environments.
How do humans use artificial propagation in agriculture?
Cuttings: Stem/leaf segments rooted in soil (e.g., roses).
Grafting: Combining scion (desired plant) with rootstock (e.g., apple trees).
What are the three components of a seed?
Embryo (develops into new plant).
Endosperm (nutrient-rich tissue).
Seed coat (protective outer layer).
How do fruits form, and what is their function?
Develop from the ovary wall (pericarp) after fertilization.
Functions: Protect seeds, aid in dispersal (e.g., fleshy fruits attract animals; dry fruits use wind).
Name three seed dispersal mechanisms with examples.
Wind: Dandelion seeds (parachutes), maple samaras.
Water: Coconut (buoyant husk).
Animals: Burrs (attach to fur), berries (eaten and excreted).
Define sporophyte and gametophyte in plant life cycles.
Sporophyte: Diploid (2n), produces spores via meiosis.
Gametophyte: Haploid (n), produces gametes via mitosis.
What is parthenocarpy?
Development of seedless fruits without fertilization (e.g., bananas, seedless watermelon).
