May i, 1925 Necrosis, Hyperplasia, and Adhesions in Tomatoes 
879 
areas in the epithelium lining the locule. 
Internal intumescences of considerable 
size were found in the larger green 
fruits. Early stages in the growth of 
such intumescences are shown in Plate 
1, E, and Plate 3, F, and larger ones 
are shown in Plate 7 and Plate 8, A. 
Plate 7, A, represents a very large 
intumescence, a double outgrowth 
which measured about 2 mm. in depth. 
Most of them are not much over 1 to 
1.5 mm. in depth. Where these inter¬ 
nal intumescences impinge upon the 
placental matrix there are thin plates 
of crushed brown cells, the necrotic 
planes mentioned above (pi. 5, Cl; 
pis. 4, 7, and 8). Very often a recipro¬ 
cal and opposite hyperplastic zone has 
arisen in the placental tissue meeting 
the invading intumescence (pi. 4, A) 
or pushing up against the pericarp (pi. 
3, E; pi. 6, B) on the inner side of the 
necrotic separation plane. 
The impression is gained from the 
examination of the sections that the 
intumescences from the inner wall sur¬ 
face actually invade and crush the 
placental parenchyma, exerting con¬ 
siderable pressure thereon (pi. 7, A; 
pi. 8, A), and the same condition 
would appear to exist at the centers of 
the whorls of hypertrophied cells sur¬ 
rounding necrotic pockets (pi. 6, D). 
The thin flattened condition of the 
necrotic separation planes may be due 
to the pressure of the opposing hyper¬ 
plastic growths. This pressure might 
be one cause of the greater firmness of 
these regions noted when the tissues 
are cut. In many cases l^perplastic 
growths from the locule wall impinge 
upon ovules (pi. 5, C; pi. 7; and pi. 
8, B), and in one instance noted the 
side of a seed was indented, apparently 
by the pressure of one of these growths. 
In a few cases, evidence of hyper¬ 
trophy and hyperplasia was noted in 
the endosperm, and abnormal trans¬ 
verse walls in the palisade epidermal 
cells of the seed coat were noted in 
seeds lying near a necrotic zone in the 
placental tissue (pi. 8, B). 
Hyperplastic tissue similar to that 
found in fruits has also been found in 
the cortical tissue of peduncles and 
petioles, immediately underlying ne¬ 
crotic surface stripes. 
In the stained preparations it was 
found that the necrotic tissues tended 
to retain safranin and the living cells, 
licht green, gentian violet, or Ziehl’s 
carbol fuchsin. Both retained Haiden- 
hain’s iron-alum haematoxylin. 
A few cases of rounded dark green 
external projections or knobs on the 
older fruits due to hypertrophy of the 
interior cells of the pericarp have been 
found. These seem to represent a 
feature somewhat similar in nature to 
the abnormal projections on the fruit 
in the case of cucumber mosaic. 
ADHESIONS 
Perhaps the most interesting feature 
of the internal abnormalities in these 
mosaic tomatoes is the fact that the 
hyperplastic invasions result in actual 
and firm adhesions between the peri¬ 
carp or locule wall and the adjacent 
placental matrix and ovules (pi. 1, C; 
pi. 3, F; pi. 4, A; pi. 6, B and C; and 
pi. 8, B) and also between the placental 
matrix and the epidermis of the seed 
coat. The intervening necrotic plane 
is not usually a true separation plane, 
but seems rather to represent a plane 
of adhesion. Furthermore it is not 
always continuous, in which case the 
opposing tissues appear actually to 
fuse or grow together by infiltration 
into each other (pi. 4, B). 
This phenomenon of abnormal ad¬ 
hesions is readily demonstrated by 
peeling a segment of the pericarp from 
a locule in which case single seeds or 
groups of seeds surrounded by the 
placental matrix will pull loose from 
their normal funicular attachment and 
remain firmly adherent to the inner 
surface of the pericarp at many of the 
points where necrotic planes are lo¬ 
cated. Furthermore, these adhesions 
are readily recognizable in the manipu¬ 
lation of the razor sections. The ab¬ 
normal fusions between interior sur¬ 
faces add to the unnatural firmness of 
affected tissues, to the disarrangement 
of the ovules, and to the external mal¬ 
formations evinced by the growing 
fruits. In one case an unnatural 
groove in the fruit was attributable to 
an underlying adhesion at the corner 
of a locule. 
EXPLANATORY LEGEND FOR PLATE 4 
A. —Section through an aihesion in the angle of a locule in a mosaic tomato 11X17 mm. in diameter. The 
normal thickness of the pericirp is shown at the top. The hyperplastic growth from the placental tissue 
begins near the base of the ovule ani fir exceeds in extent the reciprocal inward growth from the pericarp 
and locule wall. The denser cell contents at tfie base of the placental hyperplasia are a common accompani¬ 
ment of placental hyperplasia. The necrotic plane parallels the carpellary walls, a feature commonly noted 
in microsjopic eximi lation of spici nens. Pheto nicrograph X 33. Unstained 
B. —Sectioi t'l'aip in a 1 lesion between pericirp (ibive) andplicental matrix in which the necrotic 
plane is discontinuous and the hyperplastic growths from pericarp and placenta have infiltrated into each 
other or fused together. The dense cell contents at the base of the placental hyperplasia are similar to those 
pointed out in A above. Fruit 25 mm. in diameter. Photomicrograph X 33. Unstained 
