Comprehensive Plant Biology: Bryophytes to Angiosperms

Vocabulary flashcards covering non-vascular plants, vascular plants, seed plant evolution, gymnosperms, and angiosperms based on plant biology lecture notes.

Angiosperms

Seed-bearing vascular plants (~300,000 species) characterized by flowers, fruits, efficient xylem vessels, double fertilization, and seeds enclosed within a fruit.

Autopolyploidy

A type of polyploidy where chromosome duplication occurs within a single species due to meiotic nondisjunction, resulting in extra chromosome sets in gametes.

Allopolyploidy

A type of polyploidy arising from hybridization between two different species with distinct chromosome counts, followed by whole genome duplication.

Terpenes and Terpenoids

A class of plant secondary metabolites with distinct aromas that act as insect repellents and defense compounds, including citronella, rubber, rosin, and amber.

Phenolics

A class of plant secondary metabolites including flavonoids that provide floral and fruit coloration, protect against UV damage, and contribute flavors like cinnamon and capsaicin.

Alkaloids

Nitrogen-containing plant secondary metabolites that function as potent toxic deterrents against herbivores and pathogens by affecting animal nervous systems (e.g., caffeine, nicotine, morphine, cocaine).

Complete Flower

A flower that contains all four primary floral organ types: sepals, petals, stamens, and pistils.

Incomplete Flower

A flower that lacks one or more of the four primary floral organ types (sepals, petals, stamens, or pistils).

Perfect Flower

A flower that possesses both male (stamens) and female (carpels/pistils) reproductive structures.

Imperfect Flower

A unisexual flower that lacks either male stamens or female carpels.

Stigma

The sticky uppermost part of the pistil that receives and recognizes pollen, allowing only compatible pollen to germinate.

Anther

The sac-like structure at the tip of a stamen where pollen grains are produced within microsporangia.

Pollination Syndrome

A specific combination of floral traits—such as color, odor, shape, and rewards—that evolved in response to natural selection by specific abiotic or biotic pollen vectors.

Domestication Syndrome

The suite of artificially selected traits in crop plants desirable to humans, such as the loss of natural seed shattering in cultivated maize.

Gymnosperms

Vascular seed plants that produce 'naked seeds' exposed on modified leaves or cones rather than enclosed within fruits.

Tracheid Torus

A flexible, valve-like central structure in gymnosperm tracheid pit membranes that regulates water flow and seals pits to prevent the spread of air bubbles.

Coralloid Roots

Specialized above-ground roots in cycads that resemble corals and harbor symbiotic nitrogen-fixing cyanobacteria.

Ginkgophyta

A gymnosperm phylum represented by a single living fossil species (Ginkgo biloba), featuring dioecious trees, fan-shaped leaves, and flagellated sperm.

Longleaf Pine (Pinus palustris)

A critically endangered southeastern US conifer reliant on frequent low-intensity fires to clear hardwood competition and promote growth through its grass and bottlebrush stages.

Gnetales

An order of gymnosperms comprising three distinct genera (Gnetum, Ephedra, and Welwitschia) that exhibit vessel-like features reminiscent of angiosperms.

Wood (Secondary Xylem)

Plant tissue composed of cellulose and water-conducting cells reinforced with lignin, produced by the vascular cambium to provide structural support and long-distance transport.

Vascular Cambium

A ring of lateral meristematic tissue in woody plants that produces secondary xylem (wood) internally and secondary phloem (inner bark) externally.

Progymnosperms

An extinct group of ancestral land plants that were the first to evolve wood and a vascular cambium, but reproduced via spores rather than seeds.

Pollen Grain

A resistant, sporopollenin-coated microspore containing a reduced, multicellular male gametophyte capable of producing sperm cells.

Seed

A mature, fertilized plant ovule consisting of a protective seed coat (testa), an embryo, and stored nutritive tissue.

Double Fertilization

A process in angiosperms where one sperm fertilizes the egg cell to form a diploid $2n$ zygote, while a second sperm fuses with two polar nuclei to form triploid $3n$ endosperm.

Imbibition

The initial uptake of water by a dry seed, causing the seed coat to swell and split to activate plant metabolism.

Coleoptile

A protective sheath covering the emerging shoot tip (plumule) in germinating monocot seedlings.

Radicle

The embryonic root of a seed plant that first emerges from the seed coat during germination.

Tracheophytes

Vascular plants (~280,000 species) possessing specialized fluid-conducting cells called tracheids reinforced with lignin.

Lignin

A tough, complex organic polymer embedded in vascular plant cell walls that provides structural rigidity and permits high turgor pressure.

Rhizome

A horizontal underground stem that produces roots and shoots from its nodes, present in lycophytes, pteridophytes, and angiosperms, but absent in gymnosperms.

Microphyll (Lycophyll)

A small, simple leaf containing only a single, unbranched strand of vascular tissue, characteristic of lycophytes.

Euphyll (Megaphyll)

A leaf with a complex, branched vascular system that evolved from flattened stem branch systems, typical of ferns and seed plants.

Apical Meristem

A region of actively dividing cells at the tips of stems and roots that drives primary vertical plant growth.

Sori

Clusters of sporangia located on the undersides of mature fern fronds (euphylls) that produce haploid spores.

Bryophytes

Small, nonvascular land plants (liverworts, hornworts, and mosses) lacking true roots, stems, and leaves, featuring a dominant haploid $n$ gametophyte generation.

Rhizoids

Rootlike elongated filaments in bryophytes that function primarily to anchor the plant to a substrate rather than transport water.

Antheridia

Multicellular male gametangia that produce flagellated sperm cells requiring water to swim to the egg.

Archegonia

Flask-shaped female gametangia that enclose and protect a single egg cell.

Matrotrophy

The process by which a developing diploid $2n$ embryo is sheltered and nourished within the tissues of the maternal gametophyte.

Sporopollenin

A highly resistant polymer forming the protective outer walls of plant spores and pollen grains, preventing desiccation and decay.

Gemma Cups

Cup-like structures on the thallus of liverworts containing gemmae (haploid tissue discs) used for asexual reproduction when splashed by raindrops.

Operculum

The protective cap or lid on a moss sporangium capsule that detaches upon maturity to allow spore dispersal.

Peristome Teeth

A ring of specialized tooth-like structures around the opening of a moss capsule that flex in response to humidity changes to flick spores outward.

Chlorophyta

Green algae clade sharing key ancestral traits with land plants, including chlorophylls $a$ and $b$, cellulose cell walls, and starch storage.

Rhodophyta

Red algae group primarily found in deep marine environments, utilizing the accessory pigment phycoerythrin to absorb blue light.

Phaeophyta

Brown algae group consisting of multicellular seaweeds that utilize fucoxanthin as an accessory pigment and include large kelps.

Accessory Pigment

Light-absorbing molecules (such as carotenoids, phycoerythrin, and phycocyanin) that capture light wavelengths not absorbed by chlorophyll $a$ and transfer energy to photosynthetic reaction centers.

Thallus

The complete plant-like vegetative body of a seaweed or macroalga that lacks true vascular tissue differentiation into leaves, stems, or roots.

Seagrass

A fully submerged marine angiosperm possessing true vascular tissues, roots, leaves, flowers, and internal seed production.

Charophyceans

The group of green algae most closely related to land plants, sharing traits like plasmodesmata, phragmoplasts during cell division, and flagellated sperm.

Placental Transfer Tissue

Specialized parent gametophyte cells with inner cell wall ingrowths that maximize surface area for transferring nutrients to the developing $2n$ embryo.

Bryophytes

Small, non-vascular land plants (liverworts, hornworts, and mosses) characterized by a dominant, long-lived haploid $n$ gametophyte generation and water-dependent fertilization.

Archegonia

Flask-shaped female gametangia in bryophytes and seedless vascular plants that enclose and protect a single egg cell.

Antheridia

Multicellular male gametangia that produce flagellated sperm cells requiring water to swim to the egg.

Gemma Cups

Cup-like structures on the thallus of liverworts containing discs of tissue (gemmae) that are dispersed by rain splashing for asexual reproduction.

Peristome Teeth

Hygroscopic tooth-like structures framing a moss capsule opening that flex in response to humidity changes to flick spores outward.

Tracheophytes

Vascular plants possessing specialized fluid-conducting tracheids reinforced with lignin, enabling tall upright growth.

Lignin

A complex organic polymer embedded in secondary cell walls of vascular plants that provides mechanical rigidity and supports high turgor pressure.

Euphyll (Megaphyll)

A leaf featuring a complex, branched vascular system that evolved from flattened stem systems, characteristic of ferns and seed plants.

Sori

Clusters of sporangia located on the undersides of mature fern fronds (euphylls) that produce and release haploid spores.

Progymnosperms

An extinct group of ancestral land plants that evolved wood and a vascular cambium prior to seeds, reproducing via spores.

Wood (Secondary Xylem)

Secondary plant tissue produced internally by the vascular cambium, composed of cellulose and water-conducting cells reinforced with lignin for long-distance transport and structural support.

Heterospory

The production of two distinct types of spores: microspores that develop into male gametophytes and megaspores that develop into female gametophytes.

Seed

A mature, fertilized plant ovule consisting of a protective seed coat (testa), stored nutritive tissue, and an embryonic sporophyte.

Radicle

The embryonic root of a seed plant that first ruptures the seed coat during germination to anchor the plant into soil.

Coleoptile

A protective cylindrical sheath covering the emerging shoot tip (plumule) in germinating monocot seedlings.

Tracheid Torus

A flexible, valve-like central structure in gymnosperm pit membranes that seals pits during pressure loss to prevent air bubble embolisms from spreading.

Coralloid Roots

Specialized above-ground roots in cycads that harbor symbiotic nitrogen-fixing cyanobacteria.

Ginkgophyta

A monotypic gymnosperm phylum represented by Ginkgo biloba, featuring dioecious trees, fan-shaped leaves, and flagellated sperm.

Ovule Cones

Complex woody seed cones positioned higher in conifer canopies that contain megasporangia and receive windborne pollen.

Longleaf Pine (Pinus palustris)

A critically endangered southeastern US conifer reliant on frequent low-intensity ground fires to clear hardwood competition and stimulate growth out of its grass stage.

Angiosperms

Seed-bearing vascular plants characterized by flowers, fruits, vessel elements in xylem, double fertilization, and seeds enclosed within an ovary.

Double Fertilization

A reproductive process in angiosperms where one sperm fertilizes the egg cell to form a diploid $2n$ zygote, while a second sperm fuses with two polar nuclei to form triploid $3n$ endosperm.

Autopolyploidy

A type of genome duplication resulting from meiotic nondisjunction within a single species, producing extra chromosome sets in gametes.

Terpenes and Terpenoids

A class of plant secondary metabolites with distinct aromas that act as insect repellents and defense compounds, including citronella, rubber, and resin.

Phenolics

A class of plant secondary metabolites including flavonoids that protect against UV radiation, provide floral colors, and produce flavors like cinnamon and capsaicin.

Alkaloids

Nitrogen-containing plant secondary metabolites that act as potent toxic deterrents by disrupting animal nervous systems (e.g., caffeine, nicotine, morphine, cocaine).

Stigma

The sticky uppermost surface of the carpel/pistil that receives, recognizes, and selectively permits pollen germination.

Perfect Flower

A flower that contains both male stamens and female carpels/pistils, regardless of whether petals or sepals are present.

Pollination Syndrome

A specific suite of floral traits—such as color, odor, shape, and rewards—that evolved in response to natural selection by specific abiotic or biotic pollen vectors.

Domestication Syndrome

The suite of artificially selected traits in crop plants desirable to humans, such as the loss of seed shattering in cultivated grains.