556 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(2) Nutrition and Growth (including 1 Germination, and Movements 
of Fluids). 
Influence of the Dark Heat-Rays on the Growth of Plants. * * * § — By 
growing plants beneath a concentrated solution of alum, Herr N. H. 
Nilsson has tested the effect on their growth of the dark heat-rays as 
compared with that of ordinary sunlight. Among the more important 
uniform results are the following : — The epidermal cells are larger, and 
have more wavy walls, the outer and radial walls being thinner ; the 
quantity of hairs is reduced ; the palisade-cells are shorter radially ; and 
the intercellular spaces in the palisade-parenchyme are larger. Different 
species showed different results as respects the size of the leaves and of 
the stomates, and the absolute size of the spongy parenchyme. 
Germination of Parasitic Phanerogams.f — Herr E. Heinricher states, 
as the result of experiments on various species of Rliinanthege, that the 
germination of the seeds takes place independently of any chemical 
irritation from a host-plant ; but that the haustoria are produced only as 
the result of the chemical irritation exercised by a second living root. 
New Mode of Grafting.^ — M. L. Daniel advocates a new process of 
grafting which he terms the greffe en flute-apjproche, and which he claims 
to combine the advantages of the “ flute-method ” (greffe en flute') and 
the “ shield-method” (greffe en ecusson). It is described as being certain 
in its results, but it takes more time than the methods already in use, 
and is applicable rather to the perpetuation of special varieties than to 
use for ordinary purposes of cultivation. 
Role of Water in Growth.§— Mr. Co B. Davenport compares the 
developmental processes occurring at the tip of a twig and those in the 
animal embryo. In both there is first a period of rapid cell-division 
with slow growth ; next a grand period of growth in which the general 
form of the embryo is acquired, the rudiments of the organs are estab- 
lished, and the organism increases rapidly in size by the imbibition 
of water ; and lastly, a period in which histological differentiation is 
carried on, while the absolute growth increments cease to increase. 
Transpiration in the Tropics.|j — Erom series of observations made in 
Java and at Wageningen (Holland), Herr E. Giltay doubts the accuracy 
of Haberlandt’s statement % that transpiration is much less energetic in 
the Tropics than in the temperate climate of Central Europe. He does 
not, however, consider that any of the experiments as yet made are on a 
sufficiently extended scale to settle the question. 
Currents of Pigments and Saline Solutions in Dicotyledons.** — 
Herr E. Tschermak finds a remarkable difference between the paths taken 
by coloured solutions and by solutions of salts in the ascending current in 
dicotyledonous, woody, and herbaceous plants. The pigments employed 
were aqueous solutions of sodium-indigo sulphate, fuchsin, saffranin, 
* SB. Bot. Yerein Lund, Nov. 14, 1896. See Bot. Centralbl., lxxii. (1897) p. 21. 
f Ber. Naturw.-med. Ver. Innsbruck, xxii. (1896). See Bot. Centralbl., l x xi. 
(1897) p. 318. X Rev. Gen. de Bot. (Bonnier), ix. (1897) pp. 213-9 (12 figs.). 
§ Proc. Boston Soc. Nat. Hist., xxviii. (1897) pp. 73-84. 
|| Jahrb. f. wiss. Bot. (Pfeffer u. Strasburger), xxx. (1897) pp. 615-44. 
Cf. this Journal, 1893, p. 208. 
** SB. K. Akad. Wiss. Wien, cv. (1896) pp. 41-70. 
