Shade is the blocking of
sunlight
Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible spectrum, visible light perceptible to the human eye as well as invisible infrare ...
(in particular direct sunshine) by any object, and also the shadow created by that object. It may refer to blocking of sunlight by a
roof
A roof (: roofs or rooves) is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of tempera ...
, a
tree, an
umbrella, a
window shade or blind,
wall,
curtains, or other objects.
As a resource
In
temperate
In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...
and
tropical zones (most places on Earth), shade is an important issue in providing cooling and shelter from
harmful heat and
ultraviolet emitted by the Sun.
Plants
Green plants produce shade by absorbing sunlight to invest as energy in
photosynthesis to produce
sugar
Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose
Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...
. They also actively
transpire, producing an additional cooling effect.
In gardening terms, there are various types of shade:
*Full sun – more than five hours of direct sun per day.
*Part shade – two to five hours of direct sun, or all-day ' (sunlight shining through open trees).
*Full shade – less than two hours of direct sun per day.
Under a dense forest
canopy,
light intensity can be very low. Special
adaptations produce the
shade tolerance that allows plants to survive in the
understory.
In addition, shade within a canopy can elicit shade avoidance responses whereby plants elongate their
shoots in order to reach light for optimal
photosynthesis.
[Debatosh Da]
"Ethylene- and shade-induced hypocotyl elongation share transcriptome patterns and functional regulators"
"Plant Physiology",21-06-2016
See also
*
Shade tree, a large tree that provides shade
References
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Light
Shading