19.2 angiosperms

Flashcards covering key vocabulary and concepts related to the angiosperm life cycle.

Angiosperms

Flowering plants with highly reduced microgametophytes, indirect pollination, and seeds enclosed in an ovary that develops into a fruit.

Microgametophyte

The male gametophyte in angiosperms, highly reduced (2-3 cells).

Microsporogenesis

The formation of a microspore (single-celled pollen grain) from a microsporocyte (microspore mother cell) within the microsporangia (pollen sacs) of the anther.

Microgametogenesis

The development of a multicellular microgametophyte involving mitosis to produce a tube cell (vegetative cell) and a generative cell, which divides to form two sperm cells.

Pollen Grain

The microgametophyte of angiosperms, featuring a resistant outer wall (exine) containing sporopollenin and an inner wall (intine). Contains 2-3 nuclei when shed and germinates through apertures.

Megagametophyte

The female gametophyte, formed by megasporogenesis & megagametogenesis.

Megasporogenesis

The process where a megasporocyte (megaspore mother cell) within the nucellus (megasporangium) undergoes meiosis to form a megaspore inside the ovule.

Megagametogenesis

The development of a megaspore into a 7-celled megagametophyte (embryo sac) through three mitotic divisions, resulting in two polar nuclei in the central cell, egg apparatus, and three antipodals.

Double Fertilization

A unique process in angiosperms where one sperm fuses with the egg and the other sperm fuses with the two polar nuclei (triple fusion) in the central cell.

Endosperm

A triploid tissue formed from the triple fusion in the central cell, providing food (carbohydrates, proteins, and lipids) to the developing embryo and seedling.

Fruit

The structure developed from the ovary wall (and sometimes other floral parts) that encloses the seed.

Simple Fruit

Develops from one carpel or from several fused carpels of one gynoecium and can be either dry or fleshy (1 carpel/fused carpels, 1 flower).

Aggregate Fruit

Develops from many separate carpels of one gynoecium (many separate carpels, 1 flower).

Multiple Fruit

Consists of the gynoecia of more than one flower, where each flower produces a fruit that matures into a single mass (many carpels of many flowers).