Sexual Reproduction in Flowering Plants - Vocabulary Flashcards

Flashcards covering the topics of sexual reproduction in flowering plants.

Biology

The story of life on earth, focusing on species survival through reproduction despite individual organism death.

Reproduction

A vital process for the continuation of species, occurring through asexual or sexual means.

Sexual Reproduction

Enables the creation of new variants, enhancing survival advantage.

Panchanan Maheshwari

An Indian botanist (1904-1966) known for work on embryological aspects and promoting tissue culture. Made significant contributions to school education by leading the development of the first Biology textbooks for Higher Secondary Schools published by NCERT in 1964.

Flowers

Organs of angiosperms used as symbols for conveying human feelings such as love, affection, happiness, grief, mourning, etc.

Floriculture

Deals with the cultivation of flowers for ornamental or commercial purposes.

Androecium and Gynoecium

The two main parts in a flower in which the units of sexual reproduction develop.

Pre-fertilisation Events

Hormonal and structural changes in a plant which lead to the differentiation and further development of the floral primordium.

Androecium

A whorl of stamens representing the male reproductive organ.

Gynoecium

Represents the female reproductive organ.

Filament

The long and slender stalk of the stamen.

Anther

The terminal, generally bilobed structure of the stamen.

Dithecous

Having two theca in each lobe.

Tetragonal

Four-sided structure of an anther consisting of four microsporangia located at the corners, two in each lobe.

Microsporangia

Located at the corners of the anther, they develop further and become pollen sacs, packed with pollen grains.

Wall layers of microsporangium

The epidermis, endothecium, middle layers, and tapetum.

Tapetum

Innermost wall layer of microsporangium which nourishes the developing pollen grains.

Sporogenous tissue

Compactly arranged homogenous cells occupying the center of each microsporangium.

Microsporogenesis

Cells of the sporogenous tissue undergo meiotic divisions to form microspore tetrads.

PMC

Pollen or microspore mother cell.

Pollen grains

The male gametophytes.

Exine

The hard outer layer of a pollen grain, made up of sporopollenin.

Sporopollenin

One of the most resistant organic materials known, found in the exine of pollen grains.

Germ pores

Prominent apertures on the pollen grain exine where sporopollenin is absent.

Intine

The inner wall of the pollen grain, made up of cellulose and pectin.

Vegetative cell and generative cell

Two cells found inside a mature pollen grain.

Pollen allergy

Respiratory disorders, like asthma and bronchitis, caused by pollen grains of many species.

Viability

The ability of pollen grains to remain viable, varies with species, temperature, and humidity.

Monocarpellary

Consists of a single pistil.

Multicarpellary

Having more than one pistil.

Syncarpous

When pistils are fused together.

Apocarpous

When pistils are free.

Parts of a pistil

The stigma, style, and ovary.

Stigma

The landing platform for pollen grains.

Style

The elongated slender part beneath the stigma.

Ovary

The basal bulged part of the pistil.

Placenta

Located inside the ovarian cavity.

Megasporangia/ovules

Arising from the placenta.

Ovule

A small structure attached to the placenta by means of a stalk called funicle.

Funicle

Stalk by which the ovule is attached to the placenta.

Hilum

The junction between ovule and funicle.

Integuments

Protective envelopes of the ovule.

Micropyle

Small opening in the integuments.

Chalaza

Opposite the micropylar end, is the basal part of the ovule.

Nucellus

Mass of cells enclosed within the integuments.

Embryo sac

Located in the nucellus, is the female gametophyte.

Megasporogenesis

The process of formation of megaspores from the megaspore mother cell.

Megaspore mother cell (MMC)

Cells containing dense cytoplasm and a prominent nucleus in the micropylar region of the nucellus.

Monosporic development

Development of the embryo sac from a single megaspore.

2-nucleate embryo sac

Formed when the nucleus of the functional megaspore divides mitotically.

Free nuclear divisions

Mitotic divisions that are not followed immediately by cell wall formation.

Mature embryo sac

A typical angiosperm embryo sac, at maturity, though 8-nucleate is 7-celled.

Egg apparatus

Group of three cells at the micropylar end.

Synergids

Two cells of the egg apparatus that have special cellular thickenings called filiform apparatus.

Egg cell

Cell of the egg apparatus.

Filiform apparatus

Cellular thickenings at the micropylar tip of synergids, which play an important role in guiding the pollen tubes into the synergid.

Antipodals

Three cells at the chalazal end.

Central cell

Large cell has two polar nuclei.

Pollination

Transfer of pollen grains to the stigma of a pistil.

Pollinating agents

Plants use two abiotic (wind and water) and one biotic (animals) agents.

Autogamy

Pollination achieved within the same flower.

Chasmogamous flowers

Flowers which open and expose the anthers and the stigma.

Cleistogamous flowers

Flowers which do not open at all.

Geitonogamy

Transfer of pollen grains from the anther to the stigma of another flower of the same plant.

Xenogamy

Transfer of pollen grains from anther to the stigma of a different plant.

Anemophily

Wind pollination.

Hydrophily

Water pollination.

Zoophily

Animal pollination.

Floral visitors

Pollen/nectar robbers.

Inbreeding depression

Majority of flowering plants produce hermaphrodite flowers and pollen grains are likely to come in contact with the stigma of the same flower, this results in this phenomenon.

Self-incompatibility

Genetic mechanism prevents self-pollen (from the same flower or other flowers of the same plant) from fertilising the ovules.

Monoecious

Having both male and female flowers present on the same plant such as castor and maize.

Dioecy

Male and female flowers are present on different plants, that is each plant is either male or female (dioecy)

Pollen-pistil interaction

All events from the landing of pollen grains on the stigma until pollen tubes enter the ovule.

Emasculation

Removal of anthers from the flower bud before the anther dehisces using a pair of forceps.

Bagging

Covering emasculated flowers with a bag to prevent contamination of its stigma with unwanted pollen.

Post-fertilisation events

Endosperm and embryo development, maturation of ovule(s) into seed(s) and ovary into fruit, are collectively termed this.

Endosperm

Tissue filled with reserve food materials, used for the nutrition of the developing embryo.

Free-nuclear endosperm

Successive nuclear divisions yield free nuclei.

Dicotyledonous embryo development

The zygote gives rise to the proembryo and subsequently the globular, heart-shaped, and mature embryo.

Epicotyl

Above the level of cotyledons.

Hypocotyl

Below the level of cotyledons.

Root cap

Radicle or root tip.

Coleorrhiza

Sheath enclosing radical and root cap.

Coleoptile

Hollow foliar structure enclosing a shoot apex.

Ex-albuminous seeds

Non-albuminous seeds have no residual endosperm as it is completely consumed during embryo development.

Albuminous seeds

Albuminous seeds retain a part of endosperm as it is not completely used up during embryo development.

Perisperm

Residual, persistent nucellus.

Moisture content

Seed coat becomes Relatively dry.

Dormancy

State of inactivity

Pericarp

Wall of the ovary develops into the wall of fruit.

False fruits

The thalamus also contributes to fruit formation.

Parthenocarpic fruits

Fruits develop without fertilisation.

Apomixis

To produce seeds without fertilisation.

Polyembryony

Occurrence of more than one embryo in a seed.

Syngamy

One of the male gametes moves towards the egg cell and fuses with its nucleus thus completing this process.

Triple fusion

The other male gamete moves towards the two polar nuclei located in the central cell and fuses with them to produce a triploid primary endosperm nucleus (PEN).