1908] POND—LATERAI ROOTS 415 
the lateral root the turgor is the same as that of the undisturbed 
endodermis. The turgor of the cells of the central cylinder was 
also found to be 0.5 to 1 per cent. KNO, higher than that of the 
cells of the cortex. Similar estimates were made with ammonium 
chlorid, whose osmotic pressure is practically twice that of KNO,, 
and it was found that one-half the concentration produced corre- 
sponding degrees of plasmolysis. In other sections in which the 
young lateral root is just beginning to dislocate the endodermis, the 
turgor of the endodermal cells is not so high, only about 4 per cent. 
KNO,. It is thus apparent that as the very young lateral root 
commences to make new cells, the difference between the turgor of 
the cortical cells and that of the endodermal cells covering the apex 
of the lateral root increases until it amounts to about ten atmospheres 
before the lateral root ruptures the epidermis. There can be no 
doubt that the tissue of the lateral root is capable of sustaining a growth 
push jar greater than the cortex is capable of resisting. 
I was not able to observe plasmolysis in the meristematic cells at 
the apex of the lateral root inside the endodermis. It is quite likely 
that volume determinations would have revealed some shrinkage, 
but in saturated KNO, no separation of protoplasm from the cell 
Wall was seen. It is possible that the protoplasm was suddenly 
Killed. Ruemarpt’? found that the lateral roots of Vicia Faba 
will develop and grow in solutions of sufficient concentration to 
Mortally plasmolyse the surrounding tissue. 
The penetration of one living root by another 
For the purpose of auxiliary evidence, several tests were made to 
ascertain whether one main or lateral root can penetrate another 
Tadicle. A seedling with radicle 6 or 7°™ in length was pinned to 
4 sheet of cork through the cotyledons, and under the hypocotyl, 
T or 2°" from the cotyledons, a small block of cork was placed to 
Taise the hypocotyl. A root model of glass tubing was drawn out 
and vertically held upon the hypocotyl while gypsum was placed 
‘round the tube and the seedling. As soon as the gypsum was hard 
*° REEL Kenntniss des Wachstums 
der -onebaness pateeaedens rt 0 eh ron fiir Schwendener. pp. 41- 
M14. Berlin. 1606! 
