Flowering Plants

Terms from 3/4 reading

Embryo Sac

The female gametophyte of an angiosperm located inside an ovule consisting of eight haploid cells.

Integument

The layered sporophyte tissue forming the outside of the ovule. Within it is the megaspore and then the embryo sac.

Micropyle

An opening in the integument of an ovule through which a pollen tube can enter to fertilize the embryo sac inside.

Synergid cell

Two haploid, single-nucleated cells present in an angiosperm’s female gametophyte (the embryo sac) at the micropylar end alongside the egg cell. They serve accessory functions.

Antipodal cell

Three haploid, single-nucleated cells present in an angiosperm’s female gametophyte (the embryo sac) opposite the micropylar end that serve accessory functions.

Polar nuclei

The two haploid nuclei of the central cell of the embryo sac. They both fuse with a single sperm to generate a triploid endosperm.Tube cell

Generative cell

One of two cells in a pollen grain, found inside the tube cell. It divides by mitosis to generate two sperm cells.

Double fertilization

The fertilization process in angiosperms where two sperm cells are formed, one fertilizing the egg cell to form the zygote and the other fertilizing the polar nuclei to form the endosperm.

Endosperm

A triploid tissue within an angiosperm seed that stores nutrients for the developing plant embryo.

Cotyledon

Seed leaves; embryonic structures in a seed that may be the first leaf-like structures to emerge. Often play a role in nutrient storage or transport for the developing embryo.

Monocots

A classification of flowering plants (angiosperms) characterized by having a single cotyledon, coleoptile, and other traits. Includes grasses and other relatives.

Dicots

A no-longer valid classification of flowering plants (angiosperms) characterized by two cotyledons and other traits. Used as a synonym for the valid group eudicots.Shoots

Radicle

The embryonic root that germinates from a seed and gives rise to the plant’s rot system.

Hypocotyl

The embryonic shoot that emerges from a seed. It supports the cotyledons.

Coleoptile

A hollow sheath-like structure found in monocots that emerges from the seed as the beginning of a shoot system, giving rise to the stem and first leaves.

Primary Growth

The development of new tissues in a plant through cell division that cause plant structures like roots and shoots to get longer and more branched.

Secondary Growth

The development of new tissues in certain plants through cell division that cause roots and shoots to grow wider and develop wood and bark.

Determinate Growth

Growth of an organism that has genetically predetermined limits in terms of size or number of structures after which growth will stop. Seen in humans and certain plant structures like flowers or fruits.Indeterminate Growth

Primary Root

The original, often main, mature root of a plant that develops from the radicle and may produce lateral roots.

Lateral Root

A root that branches from the primary root produced by its primary growth.

Fibrous Root System

A root system with many finely divided roots and no main central taproot. It is usually the root system found in monocots (see taproot).

Taproot

A root system with a large, usually thick primary root and many much smaller lateral roots branching from it. It is usually the root system found in dicots (see fibrous root system).

Root hair

Cellular extensions of active parts of the root that increase the surface area of the root and absorb water and nutrients from the soil.

Stem

A stalk-like vascular part of the shoot system that supports leaves and flowers and can be modified for other functions.Petiole

Leaf blade

The “main body” of a leaf usually consisting of a flat, broad surface (see petiole).

Reproductive shoots

In angiosperms, the fertile flower-bearing shoots (see vegetative shoots).

Vegetative shoot

The sterile shoots that do not produce structures for sexual reproduction (see reproductive shoot).

Axillary meristem

The buds located within the axil that are usually inactive but have the potential to produce a lateral shoot through primary growth

Nodes

The places along the shoot from which leaves branch off.

Internodes

Segments of the shoot in between nodes. Once formed, they grow a certain amount by cellular elongation, spacing the nodes farther apart.