Fruit and Seed — Core Principles

Core Principles

Fruits and seeds are fundamental reproductive structures in flowering plants. A fruit is the mature, ripened ovary, typically developing after fertilization, whose primary function is to protect the developing seeds and aid in their dispersal.

The fruit wall, or *pericarp*, can be differentiated into *epicarp*, *mesocarp*, and *endocarp*. Fruits are classified into simple (from a single ovary), aggregate (from multiple separate ovaries of one flower), and multiple (from an entire inflorescence).

Simple fruits can be fleshy (e.g., drupe, berry) or dry (dehiscent like legumes, or indehiscent like achenes). False fruits involve other floral parts in their formation, such as the thalamus in apples.

A seed is a fertilized ovule, comprising a protective *seed coat*, an *embryo* (with plumule, radicle, and cotyledons), and often a food reserve (*endosperm*). Seeds are either *albuminous* (with endosperm) or *exalbuminous* (without endosperm, food in cotyledons).

They are also classified as *monocotyledonous* (one cotyledon) or *dicotyledonous* (two cotyledons). Seed dormancy is a state of suspended growth, crucial for survival and proper timing of germination.

Seed dispersal mechanisms (wind, water, animals) ensure species propagation and colonization.

Important Differences

vs Monocotyledonous Seed vs. Dicotyledonous Seed

Aspect	This Topic	Monocotyledonous Seed vs. Dicotyledonous Seed
Number of Cotyledons	One (e.g., scutellum)	Two
Endosperm at Maturity	Usually present (albuminous)	Usually absent (exalbuminous), food stored in cotyledons
Embryonal Axis Protection	Plumule covered by coleoptile, radicle by coleorhiza	Plumule and radicle are naked (not covered by sheaths)
Cotyledon Size/Function	Small, shield-shaped (scutellum), absorbs food from endosperm	Large, fleshy, stores food
Example	Maize, wheat, rice, onion	Pea, bean, gram, groundnut

Monocotyledonous and dicotyledonous seeds represent two major groups of flowering plants, primarily distinguished by the number of cotyledons in their embryo. Monocot seeds typically have one cotyledon and often retain a large endosperm for nourishment, with their embryonic plumule and radicle protected by specialized sheaths. Dicot seeds, conversely, possess two cotyledons, which usually store the food reserves, having absorbed the endosperm during development, and lack the protective sheaths around their embryonic axis. These structural differences dictate their germination patterns and early seedling development.