Some variegations are attractive and ornamental, and many of them has
been preserved and widely cultivated.
Variegation may be due to a number of causes.
In most plant species
normally green, and variegated leaves are an uncommon
a chimera. A chimeral
variegation is due to losing the ability to produce
some of the plantís tissue, so that this tissue is no longer green.
Tissues lacking of chlorophyll are usually white or pale yellow
coloured (due to carotenoid
pigments) contrasting with the normal
green tissue. There are several forms of such variegation, depending
on the tissues that have been affected. The variegation in some forms
is unstable. The extent and nature of the variegation can vary, and
sometimes the plant will return to the green form. In others it is
stable and does not change under normal conditions. Because the
variegation is due to the presence of two kinds of plant tissue,
propagating the plant must be by a
vegetative method of
that preserves both types of tissue in relation to each other. As
these plants have some of their tissue unable to carry out
photosynthesis (albinos), the plant will be weaker than the plain green plant.
They should generally be expected to die out in the
Variegation due to
reflective effects Some variegation is
due to visual effects due to reflection of light from the leaf
surface. This can happen when an air layer is located just under the
epidermis resulting in a white or silvery reflection. It is sometimes
called blister variegation. Cyclamen hederifolium leaves show such
patterned variegation, varying between plants, but consistent within
each plant. Another type of reflective variegation is caused by hairs
on parts of the leaf, which may be coloured differently from the leaf.
This is found in various species and garden
the veins of the leaf are picked out in white or yellow. This is due
to lack of green tissue above the veins. it is due to a blister
variegation occurring along the veins.
Variegation caused by other
pigments A different cause of
variegation is the camouflage of green
pigment by other pigments, such
as anthocyanins or
betalain. This frequently expands to the entire
leaf, whit reddish or purplish patterns. On some plants however,
consistent zonal markings occur such as the common Coleus, the
variegation can be very different inside a
Virus infections may origin variegation to appear on the leaf or stem
surface. The feature is often characteristic of the
Examples are the mosaic viruses produce a mosaic type. Although these
infections are generally grave enough to affected plants, there are a
few infected plants that are grown for ornament;
Deficiency symptoms may cause a temporary or variable yellowing in
specific zones on the leaf. Iron and magnesium deficiencies make the
leaf veins remain green and the areas between the veins turn yellow.