Topic
Winter rest
About: Winter rest is a research topic. Over the lifetime, 63 publications have been published within this topic receiving 1415 citations. The topic is also known as: hibernation.
Papers published on a yearly basis
Papers
TL;DR: Dormancy of trees can be divided arbitrarily into three phases: early rest, winter rest, and after-rest, and each of these phases is marked by a distinct set of physiological processes.
Abstract: Early dormancy involves a number of phenomena: cessation of active growth, formation of terminal buds, formation of abscission layers in leaves, development of cold resistance, development of winter rest (a chilling requirement), and leaf fall. The buds of some tree species (or some races of a species) have a true rest or winter chilling requirement; usually the roots do not; perhaps the cambium does not. There is a wide range of genetic variation within and between species in response to photoperiod, winter chilling, water nutrients, and other environmental factors which affect the dormancy condition of plants. During the period of winter rest there are many metabolic and developmental processes going on in the buds and twigs. These processes include respiration, photosynthesis, some cell division, enzyme synthesis, production of growth stimulators, and dissipation of growth inhibitors. Dormancy of trees can be divided arbitrarily into three phases: early rest, winter rest, and after-rest. Each of these phases is marked by a distinct set of physiological processes. The transition between the three phases is gradual. Some processes of after-rest can proceed even though the winter chilling requirement (winter rest) of a tree has not been completed fully. Evidence from grafting experiments and chemical treatments to break winter rest, and studies of genetic variability indicate that the processes and phenomena of dormancy are at least partially independent of each other. Different buds and branches and other parts of the same plant may initiate dormancy, break dormancy, and renew vegetative growth independently. Initiation and cessation of dormancy can be triggered by a number of environmental variables: photoperiod, temperature, nutrition, water, an array of chemicals, and shock treatments. Dormancy regulation must either involve a variety of receptors or involve receptors that are responsive to a variety of stimuli. Unless dormancy is defined in a highly restricted sense (that is, possession of chilling requirement), it is hard to conceive of a single receptor or regulator that controls all of the phenomena of dormancy. A large number of genes are definitely involved and hence a large number of enzymes. The kinds of enzymes, their numbers, and their concentrations can be regulated by manipulating the environment.
322 citations
TL;DR: The seasonal variation in temperature exerts as powerful a thermal influence toward differentiating insulation as does the geographical difference in temperature from the arctic to the tropics.
Abstract: IN WINTER the arctic air can be 900 colder than the normal animal's body. In the tropics the cold air may be only 100 colder. Animals well adapted to each region have insulation which is proportional to the differences between their bodies and the air, and good arctic insulation is about nine times that used in the tropics (Scholander, Walters, Hock, and Irving, 1950). This comparison indicates the plasticity of insulation in the geographical regions which are most diverse in temperature. Arctic summer can be as warm as the little-varying heat of the tropics. The seasonal variation in temperature exerts as powerful a thermal influence toward differentiating insulation as does the geographical difference in temperature from the arctic to the tropics. There is a contrast between the seasonal and geo-
202 citations
TL;DR: It is suggested that stream-dwelling trout suffer a metabolic deficit during acclimation to rapidly declining water temperatures in November/December, which has important physiological implications for overwinter survival.
Abstract: The feeding of brook and brown trout in a temperate Canadian stream was studied over two winters. Stomach analyses indicate that feeding continues throughout the winter. Both species had similar diets. Despite continuous feeding, condition factors declined significantly in early winter and remained low until the spring, suggesting an early-winter depletion of lipid reserves. Energy (calorific) intake was similar in winter to that found in late summer or spring and therefore was not the cause of low winter condition. The derived energy from feeding was insufficient to offset the costs of maintenance metabolism in the early winter period, for both immature and recently spawned fish. It is suggested that stream-dwelling trout suffer a metabolic deficit during acclimation to rapidly declining water temperatures in November/December. Such a phenomenon has important physiological implications for overwinter survival.
175 citations
TL;DR: It is concluded that some step leading to flowering and which determines the differences in sensitivity of the buds to this growth regulator has taken place already at this early date.
Abstract: In the Satsuma mandarin (Citrus unshiu Marc.) the presence of the fruit results in a gradual inhibition of flowering and of bud sprouting. This inhibitory effect starts several months before the onset of the winter rest period and lasts until the end of the accumulation of carotenoids in the fruit peel, more than one month after the completion of fruit growth. During all this time and until natural bud sprouting, flowering and bud sprouting are inhibited by exogenous gibberellic acid. Peak responses to this growth regulator coincide with periods of maximal rates of flowering inhibition by the fruit. Kinetin and abscisic acid, applied at the time of peak response to gibberellic acid, inhibited flowering and reduced the number of shoots developed through the reduction of the number of shoots formed per sprouted node, but failed to reduce the number of nodes which sprouted. The same pattern of sprouting was obtained in trees treated with gibberellic acid during the winter rest period or several months earlier. It is concluded that some step leading to flowering and which determines the differences in sensitivity of the buds to this growth regulator has taken place already at this early date.
68 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2017 | 1 |
| 2016 | 1 |
| 2014 | 3 |
| 2012 | 2 |
| 2011 | 1 |