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Family:
Cactaceae (Cactus
Family)
Scientific name:
Astrophytum asterias
(Zucc.) Lem
forma albina
Conservation status:
Artificial cultivar not listed..
Origin:
Garden origin (Nursery
produced cultivar)
albinism,
schizochromism &
Variegation:
Albinism: Every once in a while a plant exhibits
albinism (completely lacking chlorophyll pigment). This
means that its tissue is unable to carry out photosynthesis.
The result is a completely cream-white yellow or reddish plant. This
plant will be weaker than a green plant, and albinism is generally a
fatal trait (it can't produce its own food and it's not getting it from
anything else). Without chlorophyll, the albino plant has no way to
manufacture the food needed for survival and growth to maturity. This
implies that these plants cannot survive on their own roots and
necessitate being grafted on a normal green plant that provides food.
Some of these albino plants are indeed very popular, and sought after by
collectors.
Schizochromism: The yellow or red appearance of some plants is
more precisely caused by another aberration called "schizochromism".
Here, though, the specific green pigment (chlorophyll) is missing: every
other pigment is present at normal levels. The dominant green
colouration is lost, but the plant will still more than likely have
normal other pigments that give the yellow overall appearance of stems
and the red colouration of spines.
Variegation: A variegated plant has sectors, patches or stripes
with two or more different colours, even distinct shades of green.
Plants with variegated stems or leaves are often
attractive and
highly prized.
In most species the
stems or leaves are normally green, and variegated epidermis is an
uncommon
mutation, termed a
chimera. A chimeral variegation is due to losing the ability to
produce
chlorophyll in some of the plant’s
tissue, so that this tissue is no longer green. Tissues lacking
chlorophyll are usually white or pale yellow coloured (due to
carotenoid
pigments) or red (due to
betalain or
anthocyanin pigments) contrasting with the normal green tissue.
There are several forms of 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
propagation that preserves both types of tissue in relation to each
other.
Cultivation: Variegated and albinos cacti are regarded as choice and
difficult in cultivation, but despite
that many of them
are relatively easy to grow. But be aware that they
cannot tolerate prolonged exposure to direct sun light (especially
during the hottest summer days), so grow them in half-shade or
under filtered sun. They are sometime seen as grafted plants, but
many grow well on their own roots, too.
On the contrary,
the albinos can survive only if grafted on a strong green base.
Use mineral well-permeable substratum with little organic matter (peat,
humus). Water sparingly from March till
October and keep perfectly dry in winter at
temperatures from 5 to 15 degrees centigrade. (In
general these plants are more tender and cannot endure freezing
temperatures ) In the rest period no high atmospheric humidity!!
Propagation: Almost usually by seed. Plants are often grafted
onto column-shaped cacti.
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