Definition

1. Noun:
   • A completely straight ovule with the micropyle at the apex: In botany, an orthotropous ovule is a type of ovule (the structure in seed plants that develops into a seed after fertilization) that is upright and symmetrical. Its chalaza (the base where the integuments and nucellus are joined), funiculus (stalk), and micropyle (the opening for pollen tube entry) are all aligned in a straight vertical line, with the micropyle positioned at the top, opposite the stalk.

Usage Examples

• Noun:
  • The plant family Piperaceae is characterized by having an orthotropous ovule.
  • In an orthotropous ovule, the micropyle is located directly at the apex, above the chalaza.

Advanced Usage

• Botanical Description: The term is used in precise morphological descriptions to classify and contrast ovule types, the other main forms being anatropous, campylotropous, and amphitropous.
  • The orthotropous condition is considered the most primitive type among flowering plants.

Variants and Related Words

• Orthotropous (adj): Describing the characteristic of being straight and upright, with the micropyle at the apex.
  • The ovule is orthotropous.
• Ovule (n): The structure in seed plants that contains the female gametophyte and develops into a seed.
• Micropyle (n): The small opening in the integuments of an ovule through which the pollen tube typically enters.
• Anatropous ovule (n): A common ovule type that is inverted and bent back upon itself.

Synonyms

• Atropous ovule: A less common synonym for orthotropous ovule.

Related Terms (Conceptual Grouping)

• Ovule orientation: A key concept in plant morphology for which 'orthotropous' is a primary category.
• Seed development: The broader biological process in which the orthotropous ovule is a structural stage.

Noun

1. a completely straight ovule with the micropyle at the apex