May i, i92o Necrosis, Hyperplasia, and Adhesions in Tomatoes 
877 
and atrophied or necrotic weakened 
places occur commonly in the loeule 
walls. Necrotic regions are found 
within the endosperm of the ovule and 
occasionally in the embryo, and com¬ 
plete necrosis and atrophy of certain 
ovules is of common occurrence. The 
brown spots on the seeds previously 
mentioned are due to necrotic areas in 
the outer part of the endosperm just 
under the seed coat. The occurrence 
of these symptoms within the seed is 
of peculiar interest in view of the fact 
that the disease apparently is not seed- 
transmitted. 
Necrotic tissue is most abundant in 
the peripheral regions of the placental 
matrix (pi. 4, A; pi. 6, C). The more 
extensive necrotic areas seem to origi¬ 
nate very frequently in epithelial tis¬ 
sues such as the lining of the loeule and 
the surfaces of the placental matrix. 
In almost all cases except within the 
endosperm of the seed the necrotic cells 
soon collapse (pi. 6, D) and the ne¬ 
crotic tissue frequently surrounds or 
borders upon cavities of varying extent 
resulting from the collapse and shrink¬ 
age of the cells (pi. 1, E; pi. 3, F). 
The collapsed necrotic regions are 
practically always accompanied and 
bordered or more or less surrounded by 
zones of closely packed hypertrophied 
cells elongated toward the necrotic re¬ 
gion or by zones of hyperplastic tissue 
composed of more or less parallel col¬ 
umns of somewhat rectangular, closely 
packed, meristematic cells (pi. 1, C 
and D; pi. 6, C and D). This tissue 
apparently arises from the living paren¬ 
chyma cells bordering on the necrotic 
region and is characterized by reduced 
intercellular space, a condition which 
accounts in part for the translucent ap¬ 
pearance of these zones (pi. 4, A). 
These cells by radial elongation and fre¬ 
quently by transverse division produce 
the columnar tissue which grows and 
pushes in toward the necrotic region 
(pi. 7, B). Numerous instances of 
marked spherical hypertrophy of indi¬ 
vidual cells and radial hypertrophy of 
groups of adjacent cells in the epitheli¬ 
um lining the locular cavity have been 
noted opposite necrotic ovules in young 
ovaries. The latter condition is inter¬ 
preted as the incipient stage of hyper¬ 
plastic growth. 
When the necrosis occurs in the in¬ 
terior tissues of the pericarp, loeule 
wall, or placenta, the response of the 
surrounding tissue is largely hyper¬ 
trophy alone, the cells enlarging and 
elongating in toward the necrotic region 
as the latter collapses and shrinks (pi. 
1, C and D; pi. 6, C and D). Elonga¬ 
tion of endosperm cells also occurs. 
On the other hand, when the necrosis 
occurs in the epithelial tissues, such as 
the epidermis, the epithelium lining the 
locules, and the epithelium of the pla¬ 
cental matrix, the response of the un¬ 
derlying and adjacent cells, particularly 
those of the pericarp and loeule wall, is 
elongation followed by transverse divi¬ 
sion with the resultant production of in¬ 
tumescences (pi. 1, E; pi. 3, F; pis. 
4, 5, 7, and 8). 
At the bases of the hyperplastic 
growths, or intumescences, hypertro¬ 
phied cells are very conspicuous, while 
the cells in the distal portions or ad¬ 
vancing faces of these hyperplastic 
growths, the part nearest the necrotic 
tissue, are much smaller than nor¬ 
mal cells (pi. 5, B; pi. 7, A and B; pi. 
8, A). In the larger growths, or intu¬ 
mescences, the parallel nature of the cell 
columns may become deranged by the 
pressure from basal groups showing re¬ 
newed or more rapid growth, possibly 
in response to secondary necrotic areas 
within the intumescence (pi. 7, B). 
In the basal region of hyperplastic 
zones originating in the placental ma¬ 
trix, the cell contents are dense and 
brownish (pi. 4, A and B). 
The most extensive development of 
these hyperplastic zones is on the inner 
surface of the pericarp and on the loeule 
walls, particularly at the outer angles 
of the loeule, in response, it would 
appear, to peripheral necrosis of the 
adjacent placental matrix or to necrotic 
E X PL AN A TOBY LEGEND FOR PLATE 3 
A—Two young fruits cut across to show internal necrotic regions and translucent zones aheut the lining 
of the locules and in the placentae and pericarp 
B. —Badly affected young fruit showing rupture of pericarp and deep-seated internal brown discoloration 
along the sutures. Such fruits contain an abundance of internal necrosis and hypoplasia 
C. —Two ruptured and deformed fruits with mere remnants of a pericarp as a result of necrotic or atrophic 
lesions in the young ovary wall, such as are shown in Plate 2, A 
D. —Deep cracking of a fruit that w T as affected with necrotic lesions when very young 
E. —Section of a pericarp lesion showing the collapse of a subepidermal necrotic region involving the entire 
thickness of the pericarp. At either side hypertrophied cells may be seen, and the placental matrix bounded 
by a necrotic plane has pushed up under the pericarp lesion. Such a lesion would be ruptured by the sub¬ 
sequent growih of the fruit. Photomicrograph X 33. Stained with carbol fuchsin. Fruit 12 mm. in 
diameter 
F. —Section of an intumescence on a radial loeule wall extending in tow r ard the necrotic surface of the pla¬ 
cental matrix and adhering to the latter at one point. The hyperplasia originates in the subepithelial 
layers. Photomicrograph X 33 from longitudinal section of a fruit 12 mm. in diameter, stained with Haiden- 
hain’s iron-alum haematoxylin 
