AMERICAN 
JOURNAL OF BOTANY 
Vol. VII February, 1920 No. 2 
EFFECT ON CHESTNUTS OF SUBSTANCES INJECTED INTO 
THEIR TRUNKS 
Caroline Rumbold 
These observations are based on tree injectiojis made during the summers 
of 1912, 1913, 1914, and 1915.^ All the trees were orchard chestnuts: 
Paragon scions grafted on Castanea dentata. 
Trees Injected with Dyes 
Some evidence concerning the path of the injected solution in the tree 
was obtained from stains. In 1912, o.oi percent solutions of eosin, methyl 
green, and Congo red were injected into the trees. Although the holes 
were cut into the heartwood, the stains were found in the vessels of the 
youngest, or last annual ring; from here the stain spread slightly through 
the surrounding tissue. It was found that the stain descended as well as 
ascended in these vessels. In the roots the path of the' stain was not fol- 
lowed to the root tips; it was found in the ring of vessels. In the small 
branches and twigs of the tree the stain often encircled the wood, whereas 
in the trunk lower down it had been seen in patches only in the last year's 
ring of vessels. The dyes varied in their effect on the trees. The eosin 
stain passed into the leaves of the injected trees and was toxic in the dilu- 
tion used. Methyl green was not a good stain in that the color showed a 
tendency to fade. Illustrations of sections of these injected trees are in 
the report of the physiologist of the Pennsylvania Chestnut Blight Com- 
mission for the year 1912.^ 
In 1913, the non-toxic dyes, methylene blue^ Congo red, and trypan 
blue, in 1/40 percent solution were injected for twenty days into six small 
trees, the injections starting April 16. At first the solutions flowed rapidly 
into the trees, especially the methylene blue, then more slowly, and had 
practically ceased going in when the injections were stopped. The trees 
were cut down in October. Two of these trees were infected with the 
1 Rumbold, C. The injection of chemicals into chestnut trees. Amer. Journ. Bot . 
7: 1-20. 1920. 
2 Rumbold, C. Report of the physiologist. Report of the Pennsylvania Chestnut 
Tree Blight Commission, Harrisburg, July i to December 31, 1912, pp. 45-47, figs. 43-47. 
1913. 
[The Journal for January (7: 1-44) was issued February 25, 1920.] 
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