Why does grass turn yellow under all things, but not under a snow cover?

What makes the grass green, is chlorophyll. With chlorophyll, the plants can breathe, it makes sure that the photosynthesis is possible. But however, for photosynthesis the plant needs light and air.

If now anything is lying on the plants, such as a heavy stone or a piece of wood, no air and no light comes on the leaves and accordingly photosynthesis and gas exchange (oxygen and carbon dioxide) is disabled or not possible at all.

With this, the green chlorophyll abolishes (the lawn turns yellow) and accordingly the plant begins dying slowly (up to a certain point they can certainly still recover).

But where is the difference with a snow cover?

There are several reasons why the green grass remains under snow: First, under the snow there is still a small layer of air and in snow there is also a lot of air bound. In addition, the snow is often so transparent to light that the plant still receives enough light. Moreover, the metabolism of grass in the winter in anyway is reduced, and therefore all the criteria are met, that the green grass remains under the snow in winter.

It is different, of course, under a meter high, air and light impervious tight trampled snow cover. Here again, the grass will become yellow.
2012-01-29 at 01:28