Bio 102 LAB Plants 2

Osmosis

The passive diffusion of water across a semipermeable membrane.

Water Potential

A measurement combining solute concentration and physical pressure that determines water movement.

Cohesion

The intermolecular bonding of like molecules, which holds a substance together.

Adhesion

The attraction of one type of molecule to a different type.

Capillary Action

The elevation or depression of a liquid where it contacts a solid surface, driven by adhesion, cohesion, and surface tension.

Casparian Strip

A waxy layer of suberin in endodermal cells that seals off the apoplast route into the stele.

Root Pressure

The upward push of fluid in the xylem resulting from water and mineral buildup in the stele.

Transpiration

The evaporative water loss from the aerial portions of a plant.

Guard Cells

Cells flanking stomata that regulate gas exchange and water loss by changing shape via potassium ion shifts.

Sporophyte Generation

The diploid phase of a plant life cycle that produces haploid spores by meiosis.

Gametophyte Generation

The multicellular haploid phase that produces gametes.

Double Fertilization

An angiosperm process where one sperm fertilizes the egg and another fertilizes the polar nuclei to form endosperm.

Stamen

The male reproductive organ of a flower, consisting of an anther and filament.

Carpel

The female reproductive organ of a flower, consisting of a stigma, style, and ovary.

Hypocotyl

The region of the embryonic shoot below the point of cotyledon attachment, terminating in the radicle.

Epicotyl

The region of the embryonic shoot above the point of cotyledon attachment.

Scutellum

A large, thin shield-like cotyledon in monocots that absorbs and transfers food reserves from the endosperm.

Positive Phototropism

The growth of a plant shoot towards a light source.

Negative Gravitropism

The upward growth of a plant shoot against the force of gravity.

Xylem

The vascular tissue in plants that conducts water and dissolved nutrients upward from the root.

Phloem

The vascular tissue in plants that conducts sugars and other metabolic products downward from the leaves.

Stoma

A microscopic pore on the epidermis of leaves and stems used for gas exchange.

Auxin

A plant hormone that promotes cell elongation, root formation, and phototropism.

Gibberellin

A plant hormone that stimulates stem elongation, seed germination, and flowering.

Ethylene

A gaseous plant hormone associated with fruit ripening and leaf abscission.

Abscisic Acid

A plant hormone that promotes seed dormancy and stomatal closure during water stress.

Cytokinin

A plant hormone that promotes cell division, axillary bud growth, and delays leaf senescence.

Apical Meristem

The growing region at the tip of roots and shoots where cells divide to increase length.

Vascular Cambium

A lateral meristem that produces secondary xylem and phloem in woody plants.

Pollination

The transfer of pollen from the anther to the stigma of a flower.

Seed Coat

The protective outer covering of a seed, derived from the integuments of the ovule.