spor

Spor, or spore in biological contexts, is a small, usually single-celled reproductive unit capable of developing into a new organism without fertilization. In fungi, algae, bryophytes, and many vascular plants, spores function as a primary means of reproduction and dispersal. Spores differ from seeds in that they are typically unicellular and contain minimal nutrient reserves; they often germinate directly into a haploid (or sometimes diploid) organism, depending on the life cycle.

Formation, or sporogenesis, occurs in specialized structures called sporangia or on the surfaces of conidiophores or pollen sacs. In fungi, spores include sexual varieties such as asci or basidia-bearing spores and asexual varieties such as conidia. In plants, spores are produced in sporangia of the sporophyte and usually germinate to form the gametophyte.

In bacteria, endospores are highly resistant dormant forms formed under nutrient stress, enabling survival through extreme conditions; notable examples include Bacillus and Clostridium species. Spore morphology often includes protective coatings that aid durability and dispersal, with adaptations for wind, water, soil, or animal-mediated spread.

Ecologically, spores support dispersal to new habitats and persistence through unfavorable periods, facilitating life-cycle continuity across generations. They also underpin several practical areas, from agriculture and pathology to biotechnology and paleobotany, where spore dispersal and germination influence disease dynamics, fermentation processes, and reconstruction of past environments.

Taxonomy and terminology vary by language; in English, spore is standard, while some languages use the word spor for the same concept. See also sporangium, sporogenesis, endospore, conidium, and alternation of generations.