nic Plant Cloning
by Grubbycup
A
eroponic methods are commonly used in vegetative
propagation (a.k.a. cloning) by hobbyist and professional
gardeners alike. Vegetative propagation is an asexual
form of plant reproduction. A section of stem that includes
a growth tip is separated from a donor mother plant and
induced to produce roots. This effectively allows parts of
the same plant to be grown in different locations. Another
way of looking at it is the cutting will become a genetic
copy of an original plant, which is why they are referred
to as clones. Some plants are naturally specialized in
exploiting this advantage. For example, the spider plant
(Chlorophytum comosum) is a common houseplant that sends
out inflorescences (flower clusters on a stem) that include
little plantlets (clones) that can take root once in contact with
surrounding soil, eventually becoming independent plants.
Meristem Cells are Key for Cloning
Roots can be induced to form along stems due to a plant’s
meristem cells. Meristem cells start as undifferentiated
cells that can further develop into a variety of specialized
cells depending on local need. This is important to note
as all meristem cells start out the same no matter where
they are located in the plant; a fact which is exploited in
rooting cuttings. Growth tips and root tips contain such
high concentrations of these cells that they are both called
apical meristems. Secondary meristem cells are also found
along the stem, trunk, and branches, where they generally
develop to increase girth. Under proper conditions these
secondary meristem cells can be induced to instead
mature into root cells, forming new root tips.
Fortunately for many plants this can be as simple as keeping
the end of the stem opposite the growth tip moist in room
temperature conditions and under moderate lighting. There
are many ways to go about rooting cuttings. Some of the
simpler methods include placing cuttings directly into a moist
growing medium or in a glass of water set on a windowsill.
Aeroponics Made Easy
As an improvement to the basic glass-of-water method, an
air stone can be connected to an air pump and added to the
water. This adds air to the water, helping it stay oxygenated
and preventing it from going stale. While any portion
submerged would be better described as a deep water culture
(DWC), the above water stem that is exposed to the water
droplets propelled by the popping of the air bubbles benefits
from an aeroponic environment. An aerated system such as
this tends to perform better and have a higher success rate
than a simple glass of water under the same conditions.
To take this same method a step further, an air-lift driven
sprayer can be used to concentrate and raise the popping
bubble effect, allowing the ends of plant stems to stay at a
height above the waterline. Since at this point, as far as the
plant is concerned, it has stopped being air-pumped into
the water and become water-pumped into the air, it can be
considered an aeroponic system. At least until the roots grow
to the waterline. Almost all aeroponic systems eventually
become hybrid aeroponic-DWC systems at some point, as the
roots will tend to grow
down far enough to reach
the nutrient solution.
Air lifts function because
air bubbles will rise in the
“Almost all aeroponic
pipe, and water trapped
systems eventually
between air bubbles will
become hybrid
rise as well. This principle
is commonly illustrated
aeroponic-DWC
in under-gravel aquar-
systems at some point,
ium filters. Air is released
as the roots will tend
at the bottom of a riser
to grow down far
tube. As the air bubbles
rise, they carry some of
enough to reach the
the water along to be
nutrient solution.”
returned near the top of
the tank. Water from the
tank passes through the
gravel bottom to replace
the water lifted out of the tube by the air bubbles.
Air lift sprayers use a similar method. Air is pumped
through an airline into the sprayer riser near the bottom.
Nutrient solution enters through a hole in the tube and is
lifted along with the rising air bubbles. At the top end of the
tube, the bubbles burst and spray the accompanying nutrient
solution. Plant stem ends are suspended within range of the
spray, allowing them to stay moist and get nutrients.
To prevent the spray from making a mess of the
surrounding area, a lid with holes cut for plants covers
the reservoir and sprayer. The bottom end of the stem is
suspended below the lid (but above the waterline) by a
collar or net pot, with the rest of the cutting above where
it can receive moderate light. Cool (but not cold) room
temperatures are commonly considered ideal.
Maximum Yield
31