Page:Journal of botany, British and foreign, Volume 9 (1871).djvu/365

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��iiigs of the thermometer were made at 8.45 a.m. aj^ain observed at 10.30 a.m. and 11.15 a.m.


The temperature was

�� �8.45 A.M.

�10.30 A.M.

�11.15 a.m.

�Temperature of Fungus . . Temperature of Air . . .

Difference ....

�1. 12-2°


�2. 12-4° 11-2°

�124° 11-6°

�12-2° 120°





��Next morning two readings were taken at 9.10 a.m., the Fungus being warmer than the surrounding atmosphere.

�� �9.10 a.m.

�Temperature of Fungus

�1. 11-4° 10-5

�2. 11-5° 10-6°

�Temperature of Air




��On the next morning the Fungus was found to be drying up, and the observed temperature was only 0"2° higher than that of the surrounding air. The air outside the box, 11"4°; inside the box, 11'4°; temperature of Fungus, 11 '6°. No further observations were made.

A. de Bary mentions (lloft'meister, ' Handbuch der Physiologischen Eotanilc,' voi. ii. pt. 1. p. 228) that the temperature has been observed by Dutrochet in five Fungi belonging to the genera Atjaricus, Boletus, and J,ycoperdon. He. however, was only able to observe an increase of from 0"10° C. to 045° C, The greatest increase in ray specimen was noticed on the first morning of the observations, at 8.45 a.m., namely 1'2° C.

The greatest temperature is evidently produced during the night, as the difference between the temperature of the Fungus and air rapidly dimi- nished, so that at 11.15 a.m. the difference was only 0"2° C.

The difierence between the morning temperatures on the first and second day of the observations — 1'2° and 0'9° — can be easily accounted for by loss from conduction, etc., biit chiefly from the loss of heat caused by the evaporation of Avater, the weight of the Fungus having decreased from 16 oz. to 13^ oz. during the three days the experiments lasted.

The cause of the increase of temperature is due to the oxidation of the nutrient materials in the Fungus, a process depending on the absorption of oxygen, which acts on these nutrient materials, and causes various me- tamorplioses, an equivalent quantity of carbon dioxide being liberated. This metamorphosis of nutrient or assimilated materials goes on in all plants in dayliglit as well as in darkness, and is also associated with the taking up of oxygen and liberation of carbon dioxide, a process which is now recognized by all Continental ])hysiologists as the true respiration of plants. In Spirogyra we can, during the day, observe the formation of assimilated materials as starch in the cells, which contain chlorophyll. During thenitiht the assimilated material is metamorphosed or elaborated, and the cell divides and converts the assimilated material, after it has

VOL. IX. [novembeh i, 1871.] z

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