episperm
Học thuậtThân thiện
Definition
Noun: - The protective outer layer or integument of a seed, especially in flowering plants. It is the outermost part of the seed coat, derived from the outer integument of the ovule.
Usage
The term "episperm" is a specific botanical term. It is used to describe the physical structure of a seed in a scientific or academic context. - The episperm is crucial for protecting the embryo from mechanical damage and desiccation. - When studying seed morphology, one examines features of the episperm.
Examples
- Under the microscope, the thick episperm of the date seed was clearly visible.
- The hardness of the episperm can affect seed germination rates.
- Botanists noted differences in the episperm texture between the two species.
Advanced Usage
- In some seeds, the episperm becomes fused with the fruit wall, making it difficult to distinguish.
- The term is often used in contrast with "endosperm," which is the inner, nutritive tissue of the seed.
Variants and Related Words
- Testa: This is a more common synonym for the seed coat, often used interchangeably with episperm, though "testa" can sometimes refer to the entire seed coat complex.
- Seed coat: The general, non-technical term for the protective outer layer of a seed.
- Integument: The general term for a protective layer, especially in botany for the ovule and seed coverings.
Synonyms
- Testa
- Seed coat
- Outer integument (of a seed)
Antonyms
- Endosperm (the inner nutritive tissue, not a protective outer layer).
- Embryo (the developing plant within the seed, which the episperm protects).
Noun
- protective outer layer of seeds of flowering plants