theca

Thân thiện

The caterpillar's theca hangs from a twig.

Definition

1. Noun:
   • A protective case or sheath in biology: A rigid, often box-like or sac-like structure that encloses, contains, or protects something, such as a spore, pollen, or an organism during a developmental stage.
   • Specifically in botany: A capsule or sac, especially one containing spores in mosses or pollen in seed plants.
   • Specifically in zoology: The outer protective sheath of a pupa in certain insects.

Examples of Usage

• Noun:
  • Under the microscope, you can see the pollen grains developing within the theca of the anther.
  • The botanist studied the theca of the moss capsule to understand its spore dispersal mechanism.
  • The insect's theca provides a hard, protective casing during its vulnerable pupal stage.

Advanced Usage

• "Thecal" (adjective): Relating to or of the nature of a theca.
  • The thecal wall was remarkably thick and resilient.
• Used in specific taxonomic names for organisms with a prominent protective shell or test, such as some protozoans (e.g., ).

Variants and Related Words

• Thecate (adj.): Possessing or enclosed within a theca.
  • The thecate hydroid colony was anchored to the rock.
• Thecium (n.): In fungi, the layer of the fruiting body containing the asci (spore sacs). This is a related, more specific term in mycology.

Synonyms

• Case
• Sheath
• Capsule
• Sac
• Cyst (in some biological contexts)

Related Phrases / Compound Terms

• Pollen theca: The specific sac within an anther where pollen is produced.
• Theca folliculi: The outer wall of a developing ovarian follicle in mammals.
• Theca cell: A specific type of steroidogenic cell surrounding the follicle in an ovary.

Học thuật

Noun

1. outer sheath of the pupa of certain insects
2. a case or sheath especially a pollen sac or moss capsule

Từ đồng nghĩa

• sac