61 
Botany. — “The influence of temperature on the growth of the roots 
of Lepidium sativum’. By Miss E. Tarma. (Communicated 
by Prof. HW A. F.C. Went). 
(Communicated in the meeting of April 28, 1916). 
While I was engaged on an investigation of the influence of 
temperature on the growth of roots, 1. Lerrcn ') published “Some 
experiments on the influence of temperature on the rate of growth 
in Pisum sativum”. This paper reached me a short time ago, as 
did almost simultaneously an abstract of a paper by LEHENBAURR. ®) 
Although my investigations are not yet entirely completed, the above 
circumstances have induced me to publish a brief, preliminary account 
of the results obtained. Sacns mentions in his researches *) that 
probably a simple relation exists between root growth and temperature, 
but nevertheless his investigations have produced no data on 
this point. 
In connection with BLACKMAN’s views‘) and the work on the 
influence of temperature on a number of vital processes, which has 
followed his publications, it was to be expected that an investigation 
according to a more modern method than that employed by Sacus, 
should yield some new results in the case of growth also. 
The experimental object was Lepidium sativum; the seeds were 
soaked in water for one day, and then placed on vertical glass 
plates, covered with filter paper, in such a way that the rootlets 
grow down straight along the filter paper. On the third day the 
roots are placed in a thermostat: they have then attained a length 
of at least 8 m.m., so that it is possible to place a mark on an 
adult portion of the root. In the thermostat the temperature can be 
kept constant to within 0.3—0.4°, should the experiments last longer 
than 3 hours. 
In order to avoid curvature of the roots, great care must be 
taken to provide fresh air and sufficient moisture, especially at 
higher temperatures. 
Experiments in which the germination process also took place at 
a constant temperature, could not be made on account of the inade- 
quate arrangements of the laboratory; perhaps they may yet be 
possible in the near future. Germination therefore took place at 
1) Annals of Botany. January 1916. Vol. XXX. NO. CXVII. p. 25. 
*) Bot. Centrallblatt, Bd. 129. N°. 25. p. 662. 
5) Pringsheim’s Jahrbücher f. wiss. Botanik. Bd. 2. 1860 p. 338. 
4) Annals of Botany. 1905, vol. XIX p. 281. 
