^^^ Nice find.

Love the Wiki response...at least someone out there is trying...

In response to the 24hrs of light a day in Alaska...are you sure it's 24 hours of direct light? You sure it has all to do with the light, and not the temps...? What about UV and visible light refelcted off the moon? No correlation there...? There are signs from both sides of the aisle of the possibility of influence with and without dark or rest periods.

How Does Darkness Affect Plant Growth? | eHow.com

Cabbages grow big in Alaska when sunlight is abundant. The photosynthetic process occurs most readily when the sunlight available to the plant is the greatest. This is why plants in the tropics grow so large. They are near the equator where the sunlight is directly overhead much of the year. However, photosynthesis can occur in the dark. It does not occur as rapidly as during the daylight, but it is possible. If this were not the case, plants would shut down entirely every night when the sun went down.

Therefore, the periodic darkness of nighttime does not affect plant growth very much. In areas of the world, like Alaska, that experience seasonal increases in the length of daylight photosynthesis does make plants grow very large. Although Alaskan vegetable gardens are filled with plants that do well with cool temperatures and a short growing season (turnips and cabbage, for example), they tend to grow very large. This is because the sunlight hitting the gardens can do so for up to 20 hours a day.

Ecology Of The Night

Plants do not normally react strongly to the simple experience of darkness. However, autotrophic plants depend on light for their food, so darkness (the absence of light) influences their growth, and prolonged darkness is deadly. Certain unicellular algae (both marine and soil) avoid this problem in an interesting way. In light, they photosynthesize normally and make all the carbon compounds they need. But in darkness, they rapidly develop a powerful transport system that pumps external organic carbon compounds (particularly sugars) into their cells, providing an alternative source of energy and metabolites. The transport system is lost and photosynthesis begins when the light is turned on, and the rate of photosynthesis and transport may vary inversely with the light intensity. This mechanism provides a strong competitive advantage for these organisms.
The periodicity and duration of light and darkness is powerfully important in the development of many plants. The measurement by plants of light/dark periodicity enables them to fit their growth patterns to the seasons, and the duration of periodic darkness is critical for the onset of flowering in many higher plants. Thus, relatively strong light pollution during the night (as from street or flood lights) may seriously disturb the normal growth, development, flowering and senescence patterns of sensitive plants.
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In general, plants are not usually much affected by the absence of absolute darkness at night, that is, by light pollution. Bright illumination at night may affect the flowering of sensitive plants, and other aspects of growth and development behaviour, including maturation and senili-ty, may be affected. But lower levels of light pollution, which might affect animal behaviour or astronomical observation, seldom affect plants in any significant way. Plants cannot be likened to the canaries in coal mines as indicators of excessive levels of pollution.