day length


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day length

the number of daylight hours per day, increasing towards midsummer and the reverse towards midwinter. The effective trigger in the commencement and cessation of the breeding seasons in those species that demonstrate seasonal breeding.
References in periodicals archive ?
True, it will not be as high as it would under longer day length, but it will be quite acceptable.
Seeds of Juttadinteria proximus (Aizoaceae) and two species of Cheiridopsis matured during summer (when temperatures are high and day length reaches a maximum of 15 hours) differ in their germination under different temperatures, in light or dark, from seeds matured on the same shrub during winter (when temperatures are low and the shortest day length is about 11 hours) (Gutterman, 1991, 1993).
She's convinced that just 24 days of cold temperature is enough to switch butterflies' flight direction, but she's also curious about the effects of day length alone.
The first form acts in the brain and responds to the change in the day length, which we think causes behavioural changes in the young salmon to initiate their migration.
Changes in day length indicate upcoming changes in seasons, temperatures, and resources.
This gives Doha a change in day length of 3 hours 10 minutes between June and December, and the further away from the equator you travel, the greater this difference becomes.
2011); and (2) an adaptive gene (Ppd-H1, for 230 landraces) which is responsible for the control of flowering time in relation to day length (H.
Scientists can measure how fast the Earth spins by observing distant objects in space and timing how long they take to come back into view--that is one day length.
But usually the date with equal day and night lengths comes a few days before the equinox 6 plus, day length varies depending on how close you are located to the equator.
For many species, the seasonal change in day length is one of the most important environmental signals in controlling daytime rhythms (e.
THE cold of winter is partly caused by the change in day length.
Australia is a particularly good place for this type of study as it spans nearly 3000 miles from north to south, with a large variation in climate, day length and sun strength -- from Queensland in the north to Tasmania in the south.