Sexual Reproduction in Flowering Plants – Key Vocabulary

A comprehensive set of vocabulary flashcards covering the major structures, tissues, and processes involved in sexual reproduction of flowering plants, from floral organs and microspore production to ovule anatomy and embryo-sac formation.

Sexual reproduction (in plants)

Process in which flowering plants form fruits and seeds through fusion of male and female gametes.

Flower

Specialised reproductive organ of angiosperms containing male (androecium) and female (gynoecium) structures.

Inflorescence

Cluster or arrangement of flowers on a stem, arising before individual flower formation.

Androecium

Whorl of stamens in a flower representing the male reproductive organ.

Gynoecium

Whorl of carpels/pistils in a flower representing the female reproductive organ.

Stamen

Male reproductive unit of a flower consisting of a filament and anther.

Filament

Slender stalk of a stamen that supports the anther and attaches to the thalamus or petal.

Anther

Terminal bilobed structure of a stamen that contains microsporangia and produces pollen grains.

Dithecous (bilobed) anther

Anther with two lobes, each lobe containing two theca (microsporangia).

Microsporangium

Pollen sac inside an anther where microspores develop into pollen grains.

Sporogenous tissue

Central mass of cells in each microsporangium that gives rise to pollen mother cells.

Pollen (or microspore) mother cell

Diploid cell in the sporogenous tissue that undergoes meiosis to form microspores.

Microsporogenesis

Formation of microspores (pollen grains) from pollen mother cells through meiosis.

Microspore tetrad

Cluster of four haploid microspores produced after meiosis of a pollen mother cell.

Pollen grain

Male gametophyte of angiosperms, typically spherical with a two-layered wall.

Exine

Hard outer wall of a pollen grain composed of sporopollenin.

Sporopollenin

Extremely resistant organic material that makes the exine durable against heat, acids and alkalis.

Germ pore

Region on the exine lacking sporopollenin through which the pollen tube emerges.

Intine

Thin, continuous inner wall of a pollen grain made of cellulose and pectin.

Vegetative (tube) cell

Larger cell in a mature pollen grain containing reserve food and a nucleus; forms the pollen tube.

Generative cell

Smaller cell within the vegetative cell cytoplasm that divides mitotically to form two male gametes.

Pollen viability

Duration for which shed pollen grains remain capable of germination and fertilisation.

Pollen bank

Long-term storage of viable pollen grains (often in liquid nitrogen) for breeding programmes.

Floriculture

Branch of horticulture concerned with cultivation and marketing of ornamental flowers.

Pistil (carpel)

Female reproductive unit of a flower consisting of stigma, style and ovary.

Stigma

Receptive tip of a pistil that serves as the landing platform for pollen grains.

Style

Elongated stalk connecting stigma to ovary in a pistil.

Ovary

Basal swollen part of a pistil that encloses ovules within its cavity.

Placenta (botanical)

Region inside the ovary wall from which ovules (megasporangia) arise.

Ovule (megasporangium)

Small structure attached to the placenta that develops into a seed after fertilisation.

Funicle

Stalk that attaches an ovule to the placenta.

Hilum

Junction point where the funicle fuses with the body of the ovule.

Integuments

Protective envelope(s) surrounding the nucellus of an ovule, leaving a micropyle at the tip.

Micropyle

Small opening between integuments at the ovule’s tip through which pollen tube enters.

Chalaza

Basal region of an ovule opposite the micropyle where nucellus and integuments join.

Nucellus

Mass of nutritive cells inside an ovule that houses the embryo sac.

Megaspore Mother Cell (MMC)

Diploid cell in the nucellus that undergoes meiosis to produce four megaspores.

Megasporogenesis

Process of forming megaspores from the MMC via meiosis.

Functional megaspore

Single surviving haploid megaspore that develops into the embryo sac; other three degenerate.

Embryo sac (female gametophyte)

Haploid, multi-nucleate structure within an ovule that contains the egg apparatus and central cell.

Monosporic development

Type of embryo-sac formation where only one megaspore contributes to the female gametophyte.

Tapetum

Innermost nutritive wall layer of an anther that supports pollen grain development, often binucleate.

Monocarpellary

Gynoecium consisting of a single pistil or carpel.

Multicarpellary

Gynoecium containing more than one pistil or carpel.

Syncarpous

Condition where multiple carpels are fused into a single pistil.

Apocarpous

Condition where multiple carpels remain free and unfused.