Differences between liquid and solid endosperm structures

Key distinctions:

• Phase/material: Liquid endosperm is fluid (coconut water) filling the cavity; solid endosperm is a firm, cellular white tissue — the coconut meat.
• Cellular status: Liquid endosperm is acellular or very thin tissue; solid endosperm consists of parenchyma cells formed after cellularisation.
• Composition: Liquid endosperm is rich in sugars, amino acids, phytohormones and water; solid endosperm is rich in oils (about 46% average), proteins and storage reserves.
• Role: Liquid endosperm supplies immediate aqueous environment and nutrients; solid endosperm stores long–term reserves for seedling growth.
• Developmental timing: Liquid form appears early and persists; solid starts forming later and thickens as maturity proceeds.

Thus structurally, the liquid is an internal reservoir fluid, whereas the solid is a structured tissue of storage cells.