102 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Action of Mineral Salts on the Structure of the Lupin.* * * § — M. Das- 
sonville finds that, by growing lupin seeds in a solution of mineral salts 
(Knop’s solution), the following changes take place : — The number and 
size of the vessels is increased in all the organs, and their lignification 
retarded. The formation is promoted of a closed ring of wood both in 
tlic stem and in the root. The number of pericyclic fibres is increased, 
but their sclerification retarded. The degree of lignification of the 
endoderm of the root is reduced, while its cells show increased develop- 
ment. The cells of the pith and of the cortex are increased in size. 
Influence of Atmospheric Precipitation on the Growth of Plants.f 
— According to Herr E. Wollny, plants have no power of absorbing 
water through the leaves when these are already charged with moisture ; 
and even when they are withered, the power of absorption is very small. 
The moistening of the leaves has, however, the effect of reducing trans- 
piration. The reason why plants gathered when moist wither more 
quickly than those gathered when dry, is that the cell- walls in contact 
with water swell, and are stretched by the pressure of the cell-contents ; 
hence the micellae of the cell-wall are pressed apart, and the movement 
of water facilitated. Even heavy rain has no injurious effect on leaves. 
Injury from hail is often compensated, if the plant is in a young con- 
dition, by the luxuriant growth of lateral shoots induced by the destruc- 
tion of the primary shoots. 
- Germination of Seeds.J — Mr. F. Escombe sums up the present state 
of our knowledge respecting the power of seeds to resist unfavourable 
conditions for germination. In the latent condition he regards seeds as 
being, strictly speaking, neither alive nor dead, but as “ hypnotes ” in a 
state of “ hypnosis,” the cell-contents being in the condition of “ hypno- 
plasm.” The length of time during which seeds may remain in this 
condition, but still be capable of awakened life, is at present entirely 
undetermined, as also is the degree of cold to which they may be sub- 
jected without being killed, certainly as low as - 62° C. in a state of 
nature, and artificially probably much lower. 
(3) Irritability. 
Geocarpism of Morisia hypogaea.§ — Sig. L. Pampaloni describes 
the mechanism by which the fruit of this plant, belonging to the Cru- 
cifer®, buries itself in the soil. It consists of two distinct successive 
movements, one belonging to the lower, the other to the upper half of 
the pedicel ; they can be shown to be the result of positive geotropism 
rather than of negative heliotropism. The seed-vessels do not all mature 
below the surface of the soil ; the plant is amphicarpous, producing two 
kinds of fruit, one above, the other below the surface. 
Curvature of Hoots. |j — Mr. J. B. Pollock claims to have determined, 
as the result of experiment, that the stimulus in response to which cur- 
* Comptes Rendus, cxxv. (1897) pp. 794-7. 
t Borsch, a. d. Geb. d. Agricultur-Physik, xx. See Bot. Centralbl., 1897, Beih., 
p. 306. Cf. this Journal, 1897, p. 560. 
t Science Progress, i. (1897) pp. 585-608. 
§ Nnov Giorn. Bot. Ital., iv. (1897) pp. 424-30 (4 figs.). 
|| Bot. Gazette, xxiv. (1897) pp. 189-90. 
