May 1,1925 Necrosis, Hyperplasia, and Adhesions in Tomatoes 
887 
coloration, by raised brownish trans¬ 
lucent blisters, or by sunken necrotic 
lesions exhibiting a great variety of 
shapes and sizes and arranged in pecu¬ 
liar patterns. Such lesions on very 
young fruits result in great malforma¬ 
tion. 
Deep-seated necrosis in the pericarp 
and subsequent atrophy or collapse of 
the affected tissues result in extensive 
rupture of the fruit-wall and cracking 
of the fruit. Hypertrophic thickening 
of the pericarp was found. 
Internal necr.otic regions, surrounded 
by zones of translucent tissue, occur 
throughout the fruit, particularly about 
the periphery of the placental matrix. 
Cavities are often associated with these 
necrotic regions. 
Abnormal adhesions between the 
ovules and the placental matrix and 
between the latter and the lining of the 
locular cavity are of rather frequent 
occurrence at the necrotic planes. 
Ovules may be disarranged or abnor¬ 
mally oriented and may be retarded or 
atrophied. Seeds may show brown 
spots under the seed coat. The pla¬ 
cental matrix may develop abnormally. 
The epidermal blisters are caused by 
cushions of muriform hyperplastic 
tissue which push up under the necrotic 
epidermis. The translucent appear¬ 
ance of this tissue is caused by the re¬ 
duced intercellular space. 
The internal necrotic regions are 
usually isolated strips, pockets, or 
plates of crushed brown tissue sur¬ 
rounded or accompanied by zones of 
radially elongated cells or zones of 
hyperplastic tissue composed of parallel 
columns of meristematic cells growing 
in toward the necrotic region. Hyper¬ 
plasia is most marked in cases where 
epithelial tissues are involved. 
Rather well developed intumescences 
grow inward from the locular walls and 
invade the placental matrix, resulting 
in abnormal tissue fusions or adhesions. 
Necrosis and cell hypertrophy within 
the seed and abnormal cross walls in 
the palisade epidermal cells of the seed 
coat were found. 
Apparently hypertrophy and hyper¬ 
plasia occur only in association with 
necrosis and are responses to the latter. 
A review of the literature'on mosaic 
and related diseases shows that certain 
of these phenomena have^been pre¬ 
viously observed. 
LITERATURE CITED 
(1) Allard, H. A. 
1915. DISTRIBUTION OF THE VIRUS OF THE MOSAIC 
DISEASE IN CAPSULES, FILAMENTS, ANTHERS, 
AND PISTILS OF AFFECTED TOBACCO PLANTS. 
Jour. Agr. Research 5: 251-256, illus. 
(2) Artschwager, E. F. 
1918. HISTOLOGICAL STUDIES ON POTATO LEAF- 
ROLL. Jour. Agr. Research 15: 559-570, illus. 
( 3 ) 
1923.. OCCURRENCE AND SIGNIFICANCE OF PHLOEM 
NECROSIS IN THE IRISH POTATO. Jour. Agr. 
Research 24: 237-246, illus. 
4) Atanasoff, D. 
1922. STIPPLE-STREAK DISEASE OF POTATO. 
Meded. Landbouwhoogesch. Wageningen, 
deel 24 (verhandel. 5), 32 p., illus. 
(5) Bailey, L. H. 
1892. SOME TROUBLES OF WINTER TOMATOES. 
N. Y. Cornell Agr. Exp. Sta. Bui. 43, p. 
. 148-158 (217-224), illus. 
(6) Barrus, M. F., and Chuff, C. C. 
1922. YELLOW DWARF o t potatoes. Phyto¬ 
pathology 12: 123-132, illus. 
(7) Brandes, E. W. 
1919. THE MOSAIC DISEASE OF SUGAR CANE AND 
other grasses. U. S. Dept. Agr. Bul. 829, 
26 p., illus. 
(8) Brittlebank, C. C. 
1919-20. TOMATO diseases. Jour. Dept. Agr. 
Victoria 17: 231-235, 498-500, 1919; 18: 413-416, 
(9) Cobb, N. A. 
1902. TOMATO BLIGHTS. Agr. Gaz. N. S. Wales 
13: 410-414, illus. 
(10) Dickson, B. T. 
1922. STUDIES CONCERNING MOSAIC DISEASES. 
MacDonald Col. (Quebec) Tech. Bul. 2, 125 
p., Illus. 
(11) Doolittle, S. P. 
1920. THE MOSAIC DISEASE OF CUCURBITS. U. S. 
Dept. Agr. Bul. 879, 69 p., illus. 
(12) Gardner, M. W., and Kendrick, J. B. 
1922. TOMATO MOSAIC. Ind. Agr. Exp. Sta. Bul. 
261, 24 p., illus. 
(13) Gtlssow, H. T. 
1918. observations on obscure potato 
troubles. Phytopathology 8: 491-495, illus. 
(14) Howitt, J. E., and Stone, R. E. 
1916. A TROUBLESOME DISEASE OF ' WINTER 
TOMATOES. Phytopathology 6: 162-166. 
(15) Hunger, F. W. T. 
1905. UNTERSUCHUNGEN UND BETRACHTUNGEN 
t)BER MOSAIKKRANKHEIT DER TABAKS- 
pflanze. Ztschr. Pflanzenkrank. 15: 257-311, 
illus. 
(16) Hungerford, C. W. 
1922. LEAF ROLL, MOSAIC AND CERTAIN OTHER 
related diseases in Idaho. Phytopathol¬ 
ogy 12: 133-139, Ulus. 
(17) Kunkel, L. O. 
1921. A POSSIBLE CAUSATIVE AGENT FOR THE 
MOSAIC DISEASE OF CORN. Bul. Exp. Sta. 
Hawaii. Sugar Planters’ Assoc. Bot. Ser. 3: 
44-58, Ulus. 
EXPLANATORY LEGEND FOR PLATE 8 
A—Cross section through outer angle of a locule showing a large intumescence from the locule wall and a 
smaller one from the inner surface of the pericarp pushing a plane of crushed necrotic tissue down into the 
placental parenchyma. The normal thickness of the pericarp is shown at the upper right corner and the 
normal smooth inner surface at either side of the smaller intumescence. In the lower right corner may be 
seen the normal outer surface of the placental parenchyma or matrix that Alls the locular cavity and in the 
lower left corner is an ovule. Photomicrograph X 27. Unstained 
B.—Section through a hyperplastic growth from a locule wall (above) which has pressed a plane of crushed, 
necrotic tissue against a seed with the resultant production of a few abnormal cross walls in the palisade 
epidermal cells of the latter. This constitutes an adhesion between the locule waU and the seed coat. 
Photomicrograph X 26. Unstained 
