Plant Biology and Anatomy Flashcards

Comprehensive vocabulary flashcards covering plant chemistry, floral biology, tissue systems, and root and shoot anatomy based on lecture notes.

Sucrose

The transport form of carbohydrate energy in plants rather than glucose.

Starch

The primary energy storage carbohydrate molecule in plants, composed of polymers of $\alpha$-glucose.

Cellulose

The major structural carbohydrate in plant cell walls, composed of unbranched polymers of $\beta$-glucose.

Phospholipid

A lipid molecule consisting of a polar phosphate group head and a nonpolar fatty acid tail attached to glycerol, forming cell membranes.

Suberin

A waxy lipid material embedded in cell walls (such as cork and the endodermis) that functions to prevent water loss.

$\beta$-Sitosterol

The most abundant sterol lipid found in green algae and plants, used in cell membranes and as hormone precursors.

Secondary Metabolites

Plant biochemical compounds synthesized from primary products that are often limited in distribution and serve ecological roles such as defense, sun protection, or chemical signaling.

Alkaloids

Nitrogen-containing secondary metabolites that serve protective functions in plants and frequently possess pharmacological or medicinal properties in humans.

Terpenoids

A class of secondary metabolites composed of repeating isoprene units, including essential oils, rubber, taxol, and cardiac glycosides.

Isoprene

A volatile hydrocarbon gas emitted by certain plant leaves during environmental stress, which causes light refraction resulting in a blue haze.

Lignin

The second most abundant organic polymer on Earth after cellulose, deposited in secondary cell walls to provide tensile strength, body support, and waterproofing in xylem.

Tannins

Phenolic secondary metabolites stored within vacuoles that serve as an anti-herbivory feeding defense.

Tonoplast

The single membrane surrounding the plant cell's central vacuole.

Primary Cell Wall

The cell wall layer deposited during cell growth, composed of cellulose, hemicellulose, and pectin.

Secondary Cell Wall

A rigid wall layer deposited internal to the primary cell wall after cell expansion ceases, containing more cellulose, no pectin, and often lignin.

Middle Lamella

A pectin-rich layer that glues adjacent plant cell walls together.

Plasmodesmata

Cytoplasmic channels traversing the cell wall that connect the cytoplasm of adjacent plant cells.

Chloroplast

A double-membrane plastid containing chlorophyll, thylakoids, stroma, ribosomes, and DNA, specialized for photosynthesis.

Angiosperms

Flowering plants belonging to Phylum Anthophyta, representing the largest and most diverse group of plants with approximately $350{,}000$ species.

Flower

A system of modified leaves arranged on a determinate shoot specialized for sexual reproduction in angiosperms.

Calyx

The outermost sterile whorl of a flower, composed of all the sepals.

Corolla

The sterile whorl of a flower located inside the calyx, composed of all the petals.

Androecium

The male fertile whorl of a flower consisting of stamens, each made up of a filament and an anther containing microsporangia.

Gynoecium

The female fertile whorl of a flower composed of one or more carpels forming the pistil, which includes the stigma, style, and ovary containing megasporangia-bearing ovules.

Complete Flower

A flower that contains all four whorls: calyx, corolla, androecium, and gynoecium.

Incomplete Flower

A flower that is missing one or more of the four basic floral whorls.

Perfect Flower

A bisexual flower that possesses functional stamens and carpels.

Imperfect Flower

A unisexual flower that possesses either stamens (staminate) or carpels (carpellate), but not both.

Monoecious

Having separate male and female imperfect flowers borne on the same individual plant.

Dioecious

Having male and female imperfect flowers borne on separate individual plants.

Myrmecochory

The seed dispersal relationship between plants and ants.

Elaiosome

A specialized seed structure rich in fats and proteins that attracts ants for seed dispersal.

Pollination Syndromes

Suites of flower characteristics evolved in response to specific biotic or abiotic pollen dispersal vectors.

Protoderm

A primary meristem derived from the apical meristem that forms the future epidermis.

Procambium

A primary meristem that forms precursor cells of the primary vascular tissues (primary xylem and primary phloem).

Ground Meristem

A primary meristem that forms precursor cells of the ground tissue system surrounding the procambium.

Morphogenesis

The biological process by which a plant or organ develops its specific shape, driven by planes of cell division and expansion.

Parenchyma

Living ground tissue composed of cells with primary cellulose walls capable of photosynthesis, storage, secretion, and redifferentiation.

Collenchyma

Living, elongated ground tissue cells with unevenly thickened, non-lignified primary cell walls that provide structural support to young growing organs.

Sclerenchyma

Rigid structural ground tissue cells with thick, lignified secondary cell walls that are usually dead at maturity, comprising fibers and sclereids.

Tracheids

Long, narrow xylem conducting cells with lignified secondary walls and pits but no end-wall perforations, present in all vascular plants.

Vessel Elements

Shorter, wider xylem conducting cells found in angiosperms that feature end-wall perforations and stack end-to-end to form vessels.

Protoxylem

The earliest primary xylem formed during tissue elongation, possessing ring or spiral secondary wall thickenings that permit stretching.

Sieve Tube Elements

Living conducting cells of angiosperm phloem that lack nuclei at maturity, joined end-to-end via sieve plates to transport sugars long distances.

Companion Cells

Specialized parenchyma cells connected to sieve tube elements via numerous plasmodesmata that provide metabolic support to the sieve elements.

Trichomes

Specialized epidermal hair cells on plant surfaces that function in water absorption, solar reflection, and herbivore defense.

Periderm

Protective dermal tissue that replaces the epidermis during secondary growth, arising from the cork cambium and consisting of suberized dead cork cells.

Taproot System

A root architecture characteristic of non-monocot seed plants where a single main primary root grows downward with branching lateral roots.

Fibrous Root System

A root architecture characteristic of monocots consisting of multiple main roots of similar size without a dominant primary taproot.

Root Cap

A thimble-shaped mass of living parenchyma cells covering the root apical meristem that protects the meristem and secretes mucigel.

Mucigel

A slimy polysaccharide sheath secreted by root cap cells that helps the root tip traverse soil and creates favorable conditions for soil microbes.

Rhizosphere

The narrow region of soil directly surrounding plant roots that is modified by root secretions and associated soil microorganisms.

Symplastic Pathway

Movement of water and dissolved solutes through continuous cell cytoplasm interconnected by plasmodesmata.

Apoplastic Pathway

Movement of water and solutes through non-living plant structures, including cell walls and intercellular spaces.

Endodermis

The innermost layer of the root cortex consisting of tightly fitted cells containing the waxy Casparian strip.

Casparian Strip

A band of suberin embedded in the radial and transverse walls of root endodermal cells that blocks apoplastic movement, forcing substances symplastically across plasma membranes.

Pericycle

A ring of meristematic parenchyma cells located inside the root endodermis that gives rise to lateral roots.

Phytomere

The structural unit of a shoot consisting of a node, internode, attached leaf, and axillary bud.

Tunica-Corpus Organization

The structural arrangement of the shoot apical meristem composed of outer tunica layers dividing anticlinally and inner corpus layers dividing periclinally.

Anticlinal Division

Cell division occurring perpendicular to the surface of an organ, increasing surface area without adding cell layers.

Periclinal Division

Cell division occurring parallel to the surface of an organ, increasing the number of cell layers.

Leaf Trace

A strand of vascular tissue extending from the stem's vascular cylinder into the leaf base.

Leaf Gap

A region of parenchyma-filled ground tissue in the stem vascular cylinder directly above where a leaf trace branches off.

Phyllotaxy

The pattern of leaf arrangement along a stem (e.g., helical, distichous, opposite, or whorled).

Mesophyll

The photosynthetic ground tissue located between the upper and lower epidermis of a leaf.

Bundle Sheath

A protective layer of ground tissue cells enclosing a leaf vein that controls movement of materials into and out of vascular tissues.

Bulliform Cells

Large epidermal cells on grass leaves that lose turgor during drought, causing leaf rolling to restrict transpiration.

Kranz Anatomy

Specialized leaf anatomy in $C_4$ plants featuring prominent bundle sheath cells surrounded by concentric rings of mesophyll cells.

Hydrophyte Leaf Anatomy

Leaf structure adapted to aquatic environments, characterized by stomata on the upper epidermis, large intercellular air spaces, reduced xylem, and prominent sclereids.