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Winter rest (from the German term Winterruhe) is a state of reduced activity of plants and warm-blooded animals living in extratropical regions of the world during the more hostile environmental conditions of winter. In this state, they save energy during cold weather while they have limited access to food sources.
Deciduous trees lose their foliage in the winter. Tree growth rings are a result of winter rest, as there is rapid growth in the warmer spring, then slower growth later in the year.
Perennial and biennial herbaceous plants lose their frost-sensitive, above-ground parts before the winter, and regrow in the spring. Herbaceous plants that are annual, producing seeds before the winter, can also be considered to have winter rest in some form, because their seeds may stay inactive over the winter before germinating. Annual plants which have seeds that germinate before winter also have winter rest. Winter cereals, for example, which are sown in the fall and germinate before the frost, become dormant during the winter and actually require a few weeks of cold before they are able to flower.
Winter rest in an animal is different from true hibernation, since their metabolism is not reduced drastically. Body temperature is not significantly lowered, however their heart rate is reduced. This means that animals like the raccoon can quickly become active again if temperatures rise or the snow melts. [1] Other animals that winter rest are badgers.
Although a bear's body temperature decreases less than that of other mammals which undergo true hibernation, mostly changing around 6-7 degrees Celsius, this is a result of their large, heat-retaining body masses. [2] Their metabolism, the main indicator of hibernation, lowers significantly. [3]
Frost is a thin layer of ice on a solid surface, which forms from water vapor that deposits onto a freezing surface. Frost forms when the air contains more water vapor than it can normally hold at a specific temperature. The process is similar to the formation of dew, except it occurs below the freezing point of water typically without crossing through a liquid state.
In botany, a seed is a plant embryo and food reserve enclosed in a protective outer covering called a seed coat (testa). More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the product of the ripened ovule, after the embryo sac is fertilized by sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote and grows within the mother plant to a certain size before growth is halted.
Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It is most commonly used to pass through winter months – called overwintering.
Vernalization is the induction of a plant's flowering process by exposure to the prolonged cold of winter, or by an artificial equivalent. After vernalization, plants have acquired the ability to flower, but they may require additional seasonal cues or weeks of growth before they will actually do so. The term is sometimes used to refer to the need of herbal (non-woody) plants for a period of cold dormancy in order to produce new shoots and leaves, but this usage is discouraged.
Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ferns, bacteria, and the growth of the pollen tube from the pollen grain of a seed plant.
Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions. Organisms can synchronize entry to a dormant phase with their environment through predictive or consequential means. Predictive dormancy occurs when an organism enters a dormant phase before the onset of adverse conditions. For example, photoperiod and decreasing temperature are used by many plants to predict the onset of winter. Consequential dormancy occurs when organisms enter a dormant phase after adverse conditions have arisen. This is commonly found in areas with an unpredictable climate. While very sudden changes in conditions may lead to a high mortality rate among animals relying on consequential dormancy, its use can be advantageous, as organisms remain active longer and are therefore able to make greater use of available resources.
Plant hormones are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, including embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and reproductive development. Unlike in animals each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book.
Suspended animation is the temporary slowing or stopping of biological function so that physiological capabilities are preserved. States of suspended animation are common in micro-organisms and some plant tissue, such as seeds. Many animals, including large ones, may undergo hibernation, and most plants have periods of dormancy. This article focuses primarily on the potential of large animals, especially humans, to undergo suspended animation.
Torpor is a state of decreased physiological activity in an animal, usually marked by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability. The term "torpor" can refer to the time a hibernator spends at low body temperature, lasting days to weeks, or it can refer to a period of low body temperature and metabolism lasting less than 24 hours, as in "daily torpor".
An endotherm is an organism that maintains its body at a metabolically favorable temperature, largely by the use of heat released by its internal bodily functions instead of relying almost purely on ambient heat. Such internally generated heat is mainly an incidental product of the animal's routine metabolism, but under conditions of excessive cold or low activity an endotherm might apply special mechanisms adapted specifically to heat production. Examples include special-function muscular exertion such as shivering, and uncoupled oxidative metabolism, such as within brown adipose tissue.
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature as its own body temperature, thus avoiding the need for internal thermoregulation. The internal thermoregulation process is one aspect of homeostasis: a state of dynamic stability in an organism's internal conditions, maintained far from thermal equilibrium with its environment. If the body is unable to maintain a normal temperature and it increases significantly above normal, a condition known as hyperthermia occurs. Humans may also experience lethal hyperthermia when the wet bulb temperature is sustained above 35 °C (95 °F) for six hours.
In horticulture, the term is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than two years. The term is also loosely used to distinguish plants with little or no woody growth from trees and shrubs, which are also technically perennials. Notably, it is estimated that 94% of plant species fall under the category of perennials, underscoring the prevalence of plants with lifespans exceeding two years in the botanical world.
Heterothermy or heterothermia is a physiological term for animals that vary between self-regulating their body temperature, and allowing the surrounding environment to affect it. In other words, they exhibit characteristics of both poikilothermy and homeothermy.
Seed dormancy is an evolutionary adaptation that prevents seeds from germinating during unsuitable ecological conditions that would typically lead to a low probability of seedling survival. Dormant seeds do not germinate in a specified period of time under a combination of environmental factors that are normally conducive to the germination of non-dormant seeds.
Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions make normal activity or even survival difficult or near impossible. In some cases "winter" is characterized not necessarily by cold but by dry conditions; passing through such periods could likewise be called overwintering.
A hibernaculum is a place in which an animal seeks refuge, such as a bear using a cave to overwinter. The word can be used to describe a variety of shelters used by many kinds of animals, including insects, toads, lizards, snakes, bats, rodents, and primates of various species.
Liriope muscari is a species of flowering plant from East Asia. Common names in English include big blue lilyturf, lilyturf, border grass, and monkey grass. This small herbaceous perennial has grass-like evergreen foliage and lilac-purple flowers which produce single-seeded berries on a spike in the fall. It is invasive to North America and considered a threat to native wildlife.
The North American Arctic is composed of the northern polar regions of Alaska (USA), Northern Canada and Greenland. Major bodies of water include the Arctic Ocean, Hudson Bay, the Gulf of Alaska and North Atlantic Ocean. The North American Arctic lies above the Arctic Circle. It is part of the Arctic, which is the northernmost region on Earth. The western limit is the Seward Peninsula and the Bering Strait. The southern limit is the Arctic Circle latitude of 66° 33’N, which is the approximate limit of the midnight sun and the polar night.
Allium bisceptrum, also known as the twincrest onion or aspen onion, is a high elevation plant native to western United States. It is a perennial that thrives under damp and shady conditions or open meadows in California, Arizona, New Mexico, Nevada, Oregon, Washington, Idaho, and Utah.
In horticulture, stratification is a process of treating seeds to simulate natural conditions that the seeds must experience before germination can occur. Many seed species have an embryonic dormancy phase and generally will not sprout until this dormancy is broken.
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