Plant Tropism and Hosta Roots

16 years ago

Plant tropism is either positive or negative.

A plant suffering from too much light will have a negative phototropism or grow away from the light, the reverse is also true a plant suffering from lack of light will grow toward light because of positive phototropism, duh! Negative phototropism is so common that it has its own special name: skototropism.

Now, the interesting part, most plants are also gravitropic where the plant tends to grow towards or away from the force of gravity. Hosta roots grow toward the center of the earth (positively gravitropic). Tipping a potted hosta as little as 10 degrees will stimulate growth and do it in a hurry.

Tipping potted plants for a week one way, then tipping 10 degrees in the opposite direction for a week, then sitting the plant upright will stimulate root growth. The bad part is the foliage will grow in the opposite direction and does not return to upright growth when the plant is returned to the upright position. The foliage growth will not be a problem unless the pot is tipped for a long period of time and would not hurt the plant from one year to the next even if the pot were tipped for a long period.

Timing: 3-4 weeks after the plant has put up new growth in the spring when the foliage has slowed the growing process. This procedure will stimulate some foliage growth also but the advantage is root growth.

Decanting a potted plant and throwing the root ball on a table will stimulate root growth on all the roots not damaged or destroyed by being roughed up because of gravitropism.

Sort by:Oldest

Comments (2)

hostamanfred
16 years ago
Plants use specialized hormones known as auxins to influence the direction of growth. Auxins have two important properties: they stimulate cell division, and thus increased growth in plants, and they die in the presence of a certain stimulus, whether it be the presence of sunlight, water, or gravity. There are many different types of auxins, as many types as there are forms of tropisms, because a single type of auxin is only sensitive to one stimulus. Several different forms of auxins are present in most plants at the same time. The way auxins work is very simple. Auxins are present in the tips of shoots. These auxins die in the presence of a certain stimulus. Phototropic auxins die in the presence of sunlight. Assuming the stimulus doesn't move, they stay there, and stimulate growth. This growth causes one side of the shoot to be longer than the other, and as a result, it bends over away from the auxins and towards the stimulus. Sometimes, several auxins can counteract each other. Take for instance a shoot of ivy growing along a deck. Its feelers grip the underside of the deck, and its thigmotropic auxins die by the contact. Left alone, this would cause the ivy to grow underneath the deck. However, the phototropic auxins are dying on the opposite side of the plant because sunlight is present, and wish to move in the opposite direction. In cases such as these, the stronger stimulus succeeds in moving the plant
0
esther_opal
Original Author
16 years ago
Good work Fred,

Very interesting and complicated, the reason I stopped with whole story was the apparent value in container growing to manipulate these natural processes to our benefit.

I assume the reason plants donÂt always grow off center against a wall is the reflected light from the wall behind. Possibly suggesting it is best to plant against a white wall v black or dark wall or of course painting a wall white if planted against.

Do you try to use this biology to manipulate any of your growing?

Thanks again for the rest of the story.
0
Related Professionals
Burlington Landscape Contractors · Columbine Landscape Contractors · El Segundo Landscape Contractors · Hickory Hills Landscape Contractors · Mission Bend Landscape Contractors · Pine Hills Landscape Contractors · West Chester Landscape Contractors · White Bear Lake Landscape Contractors · Leesburg Driveway Installation & Maintenance · Columbia Fence Contractors · Hinsdale Fence Contractors · Palmetto Fence Contractors · San Antonio Fence Contractors · Sandy Fence Contractors · Whittier Fence Contractors