The recent thread in rec.gardens.edible about growing tomatoes upside
down gave me reason to pause and think. In the mid 1960s, there was
an article in Scientific American magazine about growing plants in a
simulated zero-gravity environment doing nothing more than rotating
the plant around three axes, rotating its position or orientation
automatically with motors that were kept running on a 24 hour basis.
I've long since lost or misplaced that copy of the magazine, but bagging
a plant's root system, directing the growth of the stem, and allowing
for constant reorientation of the plant as expected, ought to provide
a means of growing the stem of the corn plant into all kinds of fanciful
shapes like curlicues, pretzels, knots, and bows.

So, has anybody done this with corn yet? Does anybody have some
pictures of corn growing upside down? Can corn be made to grow upside
down, maybe by positioning a fluorescent light underneath it?

You probably would not be able to grow corn upside down because
gravitropism would cause the stem to bend back upward. Gravitropism is
usually stronger than phototropism. If you had a mutant plant that did
not respond to gravity, then you could do it. There are mutant pea
plants (ageotropum) whose roots do not respond to gravity but its
shoots do respond to gravity in the light.

There are many weeping plant cultivars (e.g. Sargent's weeping hemlock,
weeping cherry, weeping willows, weeping beech, weeping mulberry,
weeping crabapple, Cedrus atlantica 'Glauca Pendula', etc.) with branch
tips that normally grow toward the force of gravity. Rooting cuttings
from weeping branches might be an easy way of growing upside down
plants.

A clinostat is a device that slowly rotates a plant, about 1 revolution
per minute, and can prevent phototropism and gravitropism. The motion
would be like sitting a potted plant on a record turntable and spinning
it at a slower speed. If the potted plant is firmly attached to the
clinostat and then the whole apparatus is placed so the potted plant is
horizontal, then the plant should continue to grow straight. Both
gravitropism and phototropism would be negated because the plant has no
time to orient itself because it is constantly changing position
relative to gravity and any directional light source.

Reference

Jaffe, M.J., Takahashi, H. and Biro, R.L. 1985. A pea mutant for the
study of hydrotropism in roots. Science 230: 445-447.


David R. Hershey

wrote in message
oups.com...
You probably would not be able to grow corn upside down because
gravitropism would cause the stem to bend back upward. Gravitropism is
usually stronger than phototropism. If you had a mutant plant that did
not respond to gravity, then you could do it. There are mutant pea
plants (ageotropum) whose roots do not respond to gravity but its
shoots do respond to gravity in the light.

There are many weeping plant cultivars (e.g. Sargent's weeping hemlock,
weeping cherry, weeping willows, weeping beech, weeping mulberry,
weeping crabapple, Cedrus atlantica 'Glauca Pendula', etc.) with branch
tips that normally grow toward the force of gravity. Rooting cuttings
from weeping branches might be an easy way of growing upside down
plants.

A clinostat is a device that slowly rotates a plant, about 1 revolution
per minute, and can prevent phototropism and gravitropism. The motion
would be like sitting a potted plant on a record turntable and spinning
it at a slower speed. If the potted plant is firmly attached to the
clinostat and then the whole apparatus is placed so the potted plant is
horizontal, then the plant should continue to grow straight. Both
gravitropism and phototropism would be negated because the plant has no
time to orient itself because it is constantly changing position
relative to gravity and any directional light source.

Reference

Jaffe, M.J., Takahashi, H. and Biro, R.L. 1985. A pea mutant for the
study of hydrotropism in roots. Science 230: 445-447.


David R. Hershey


My father had a small elm-like tree once, the top part of which had been
grafted upside down. He didn't believe this of course but the brances were
definately pointed downwards and there was a grafting scar at the join.
Instead of the umbrella shape he was hoping for he got a weird mutant!