Northern Nut Growers Association Report of the Proceedings at the Fifteenth Annual Meeting: New York City, September 3, 4 and 5, 1924
Science
Northern Nut Growers Association Report of the Proceedings at the Fifteenth Annual Meeting: New York City, September 3, 4 and 5, 1924
Northern Nut Growers Association -- Periodicals; Nut trees -- Periodicals; Nuts -- Periodicals
It must be remembered, however, that what the animate plant transmits is
not the actual character in question, but the ability of the animate
plant to develop characteristics. By placing the plant near a black
walnut tree we do not affect anything but the capacity of the plant to
develop in certain directions.
I have shown here a diagram to illustrate a certain stock fertilization.
Here we have the plant with its stamen and pistils, the egg cells and
the pollen. There are two types of pollenization, one where the pistil
is fertilized by insects carrying sticky pollen; the other by movement
of the wind carrying the pollen. If I should believe my records, in
attempts to cross trees, I might have a cross between a birch and an
alder, in which the pollen is carried by the wind. I tried once to
hybridize pines. I put some pitch pine pollen on the female flower of
another species and seed resulted. I did this the second year and again
I got seed. The third year I put bags on the female flowers before I
could see them developing. Then I got no seeds. I believe that the
pollen which had caused the seed to set in the preceding instances had
come from the south for perhaps hundreds of miles.
There are times when the pollen of the staminate plant is all shed
before the pistillate gets ready. Sometimes we have a plant that is self
sterile. I have experimented with pollen from several different nut
trees and also with the Norway spruce. Then again, there are abnormal
cases; sometimes there is parthenogenesis. The jimson weed is the first
plant which has ever been reproduced by parthenogenesis. Since that was
discovered, an investigator in California has found a similar case in
fruit developed without pollination.
One of the most important conceptions in heredity is its effect upon
characters and factors. Take the Japanese bean here shown for example,
one dark bean and one mottled. In the next hybrid generation we find
three mottled and one dark. That is the familiar "three to one" ratio of
Mendel's law. We believe now, that all, or at least a very large
proportion of the heredity characters in plants of all kinds may be due
to a series of factors; but the habit of growth of the plant is due to a
single factor. We have the case here of a second generation of the
weeping mulberry that I crossed with the white mulberry. As a result
there was an average of three erects to one weeping one. Certain
characteristics may be made up of the inter-action of a large number of
factors. This will give a little idea as to the complexity of Mendel's
law.
How do we get new characters in nature? New types are due to the
rearrangement of previously existing characters, just as with the
old-fashioned kaleidoscope, where you turn the crank and get new
pictures. Another way is by the sudden appearance of new factors.
Public-domain text, read in full here on John Shaqi.
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