Chapter 38: Angiosperm Reproduction and Biotechnology

Vocabulary from Campbell's Biology

Flower

In an angiosperm, a specialized shoot with up to four sets of modified leaves, bearing structures that function in sexual reproduction.

Carpels

The ovule-producing reproductive organ of a flower, consisting of the stigma, style, and ovary.

Stamens

The pollen-producing reproductive organ of a flower, consisting of an anther and a filament.

Petals

A modified leaf of a flowering plant. They are the often colorful parts of a flower that advertise it to insects and other pollinators.

Sepals

A modified leaf in angiosperms that helps enclose and protect a flower bud before it opens.

Receptacle

The base of a flower; the part of the stem that is the site of attachment of the floral organs.

Ovary

In flowers, the portion of a carpel in which the egg-containing ovules develop.

Style

The stalk of a flower's carpel, with the ovary at the base and the stigma at the top.

Stigma

The sticky part of a flower's carpel, which receives pollen grains.

Ovules

A structure that develops within the ovary of a seed plant and contains the female gametophyte.

Pistil

A single carpel (a simple one of these structures) or a group of fused carpels (a compound one of these structures).

Anther

In an angiosperm, the terminal pollen sac of a stamen, where pollen grains containing sperm-producing male gametophytes form.

Complete Flowers

A flower that has all four basic floral organs, sepals, petals, stamens, and carpels.

Incomplete Flowers

A flower in which one or more of the four basic floral organs (sepals, petals, stamens, or carpels) are either absent or nonfunctional.

Inflorescences

A group of flowers tightly clustered together.

Pollination

The transfer of pollen to the part of a seed plant containing the ovules, a process required for fertilization.

Coevolution

The joint evolution of two interacting species, each in response to selection imposed by the other.

Embryo Sac

The female gametophyte of angiosperms, formed from the growth and division of the megaspore into a multicellular structure that typically has eight haploid nuclei.

Megaspores

A spore from a heterosporous plant species that develops into a female gametophyte.

Microspores

A spore from a heterosporous plant species that develops into a male gametophyte.

Pollen Grain

In seed plants, a structure consisting of the male gametophyte enclosed within a pollen wall.

Pollen Tube

A tube that forms after germination of the pollen grain and that functions in the delivery of sperm to the ovule.

Fertilization

The union of haploid gametes to produce a diploid zygote.

Endosperm

In angiosperms, a nutrient-rich tissue formed by the union of a sperm with two polar nuclei during double fertilization. It provides nourishment to the developing embryo in angiosperm seeds.

Double Fertilization

A mechanism of fertilization in angiosperms in which two sperm cells unite with two cells in the female gametophyte (embryo sac) to form the zygote and endosperm.

Seed

An adaptation of some terrestrial plants consisting of an embryo packaged along with a store of food within a protective coat.

Dormancy

A condition typified by extremely low metabolic rate and a suspension of growth and development.

Seed Coat

A tough outer covering of a seed, formed from the outer coat of an ovule. In a flowering plant, this structure encloses and protects the embryo and endosperm.

Hypocotyl

In an angiosperm embryo, the embryonic axis below the point of attachment of the cotyledon(s) and above the radicle.

Radicle

An embryonic root of a plant.

Epicotyl

In an angiosperm embryo, the embryonic axis above the point of attachment of the cotyledon(s) and below the first pair of miniature leaves.

Coleoptile

The covering of the young shoot of the embryo of a grass seed.

Coleorhiza

The covering of the young root of the embryo of a grass seed.

Imbibition

The uptake of water by a seed or other structure, resulting in swelling.

Fruit

A mature ovary of a flower. This protects dormant seeds and often functions in their dispersal.

Simple Fruit

A fruit derived from a single carpel or several fused carpels.

Aggregate Fruit

A fruit derived from a single flower that has more than one carpel.

Multiple Fruit

A fruit derived from an entire inflorescence.

Accessory Fruit

A fruit, or assemblage of fruits, in which the fleshy parts are derived largely or entirely from tissues other than the ovary.

Asexual Reproduction

The generation of offspring from a single parent that occurs without the fusion of gametes. In most cases, the offspring are genetically identical to the parent.

Fragmentation

A means of asexual reproduction whereby a single parent breaks into parts that regenerate into whole new individuals.

Apomixis

The ability of some plant species to reproduce asexually through seeds without fertilization by a male gamete.

Vegetative Reproduction

Asexual reproduction in plants.

Self-Incompatibility

The ability of a seed plant to reject its own pollen and sometimes the pollen of closely related individuals.

Totipotent

Describing a cell that can give rise to all parts of the embryo and adult, as well as extraembryonic membranes in species that have them.

Vegetative Propagation

Asexual reproduction in plants that is facilitated or induced by humans.

Callus

A mass of dividing, undifferentiated cells growing at the site of a wound or in culture.

Stock

The plant that provides the root system when making a graft.

Scion

The twig grafted onto the stock when making a graft.

Transgene

A gene that has been transferred naturally or by a genetic engineering technique from one organism to another.

Biofuels

A fuel produced from biomass.

Biomass

The total mass of organic matter comprising a group of organisms in a particular habitat.