Dormancy

Refugi Tossals Verds (dormant grape wine)

During winter dormancy, plant metabolism virtually comes to a standstill due, in part, to temperatures that slow chemical activity.

Dormancy is a vital adaptive strategy exhibited by various organisms, allowing them to navigate periods when environmental conditions are not conducive for normal growth, development, or activity. By minimizing metabolic activity during such periods, organisms conserve energy, awaiting more favorable conditions. The decision to enter dormancy can be either predictive, based on upcoming environmental changes, or consequential, in response to sudden adverse conditions.

Animals

• Hibernation: A strategy largely seen in mammals, hibernation is a deep sleep that helps animals conserve energy during food-scarce winters. Depending on the species and its habitat, hibernation can be both predictive or consequential.
• Diapause: A genetically controlled predictive dormancy seen predominantly in insects, diapause usually occurs between autumn and spring, serving as a bridge over unfavorable periods.
• Aestivation: In response to extreme heat or arid conditions, some organisms enter aestivation, a consequential dormancy. Aestivation is common among invertebrates, but vertebrates like lungfish, salamanders, desert tortoises, and crocodiles also exhibit this behavior.
• Brumation: Resembling hibernation but distinct in the underlying metabolic processes, brumation is a type of dormancy in reptiles. Initiated usually in late autumn, reptiles in brumation might wake intermittently to hydrate before resuming their dormant state, often going without food for extended periods.

Plants

Development from the seed: The seed, a marvel of nature, houses the dormant embryo of a plant. Far from being "asleep", the seed is in a state of arrested development, waiting for optimal conditions to commence growth. Depending on the species, seeds have varied dormancy patterns:

• Seed dormancy: Some seeds do not immediately germinate even under suitable conditions, allowing time for dispersal. Internal changes eventually break this dormancy, though the specifics differ across species.
• Seed hibernation: Other seeds await specific environmental triggers, like rain, temperature, or fire, to start germination. Some seeds even require passage through an animal's digestive system - a dual mechanism for dormancy and dispersal.
• Upon germination, the seed transforms into a seedling, relying on its internal nutrient stores. While initial growth is independent of soil nutrients, sunlight becomes crucial as the seed's reserves deplete. Without light, the plant's plastids remain immature, lacking chlorophyll, and the plant eventually succumbs once its reserves are exhausted.

Historically, the Judean date palm seed, approximately 2,000 years old, retrieved from Masada in Israel's Herod the Great's palace, holds the record for the oldest germinated seed. In contrast, the Coco de mer palm, or Lodoicea maldivica, produces the heaviest seed, with the entire fruit weighing up to 23 kilograms (50 pounds), typically containing a single seed.

Related pages

• Hibernation
• Seed germination
• Metabolism

Related pages

• Torpor

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