Cornell Nature-Study Leaflets: Being a selection, with revision, from the teachers' leaflets, home nature-study lessons, junior naturalist monthlies and other publications from the College of Agriculture, Cornell University, Ithaca, N.Y., 1896-1904New York State College of Agriculture
History
Cornell Nature-Study Leaflets: Being a selection, with revision, from the teachers' leaflets, home nature-study lessons, junior naturalist monthlies and other publications from the College of Agriculture, Cornell University, Ithaca, N.Y., 1896-1904
New York State College of Agriculture
Natural history; Nature study
What are these buds of the tip shoot preparing to do in 1897? We can
answer this question by going back just one year and seeing what the
buds on the lower (or older) part of the shoot did in 1896. On that part
(below B) the buds seem to have increased in size. Therefore, they must
have grown larger last year. There were no leaves borne below these
buds in 1896, but a cluster of leaves came out of each little bud in the
spring. As these leaves expanded and grew, the little bud grew on; that
is, each bud grew into a tiny branch, and when fall came each of these
branches had a bud on its end to continue the growth in the year to
come. What we took to be simple buds at 2, 3, 4, 5, 6, are, therefore,
little branches.
But the strangest part of this wonderful little twig has not yet been
seen,--the branches are of different sizes, and three of them (7, 8, 9)
have so far outstripped the others that they seem to be of a different
kind. It should be noticed, too, that the very lowermost bud (at 1)
never grew at all, but remained perfectly dormant during the entire year
1896. It will be seen, then, that the dormant bud and the smallest
branches are on the lower part of the shoot, and the three strong
branches are at the very tip of the last year's growth.
If, now, we picture the twig as it looked in the fall of 1895, we shall
see that it consisted of a single shoot, terminating at B. It had a
large terminal bud (like those at 7, 8, 9, 10), and this bud pushed on
into a branch in 1896, while three other buds near the tip did the same
thing.
[Illustration: _Fig. 216.--A two-year-old shoot from a young apple tree.
Half size._]
Why did some of these branches grow to be larger than others? "Simply
because they were upon the strongest part of the shoot, or that part
where the greatest growth naturally takes place," some one will answer.
But this really does not answer the question, for we want to know why
this part of the shoot is strongest. Probably the real reason is that
there is more sunlight and more room on this outward or upward end. In
1897,--if this shoot had been spared--each of these four largest twigs
(7, 8, 9, 10) would have done the same thing as the parent twig did in
1896: each would have pushed on from its end, and one or two or three
other strong branches would probably have started from the strong
side-buds near the tips, the very lowest buds would, no doubt, have
remained perfectly inactive or dormant for lack of opportunity, and the
intermediate buds would have made short branches like 2, 3, 4, 5, 6. In
other words, the tree always tries to grow onward from its tips, and
these tip shoots eventually become strong branches, unless some of them
die in the struggle for existence. What, now, becomes of the little
branches lower down?
II.
Public-domain text, read in full here on John Shaqi.
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