BOTANY. 909 



BOTANY. 



Report on the investigations at the climatological station of 

 Juvisy during 1899, C. Flammarion {But. Min. Agr. [M-OMce], 19 

 (1,900), A"o. 5, pj). H6O-86I1). — In continuation of the investigations 

 previously reported (E. S. R., 11, p. 907) the author reports upon the 

 effect of different colored light on the development of plants, the per- 

 sistence of the leaves of young oak trees when subjected to blue light, 

 and the action of different parts of the solar spectrum on the colora- 

 tion of plants. The experiments in radioculture, in which the effect 

 of the different solar radiations in the development of the plants was 

 investigated, gave results similar to those previously reported. The 

 author found that there was no difference due to species or varieties, 

 age of the plant, or whether shrubby or herbaceous. The maximum 

 growth alwa3"s took place in the red spectrum. 



The experiments continued with the young oak trees in the blue 

 light showed that their leaves were retained when subjected to this 

 radiation. The action seems to be explained by the statement that the 

 blue light prevents the transformation and transportation of the elabo- 

 rated material which determines the fall of the leaves. It was found 

 to have exercised some very marked influences upon the chlorophyll 

 of the leaves. 



The effect of the different radiations of the spectrum on the colora- 

 tion of plants was further investigated with the result that the different 

 portions of the solar spectrum influenced the coloration of the foliage 

 and flowers of a number of species. The author states that the action 

 of light on plant tissues is without doubt of a chemical nature, and in 

 influencing coloration the light seems to liberate certain substances 

 which react upon the chromoleucites. 



Physiological experiments on the germination and grovrth of 

 plants in rarefied air, F. Schaible {Beltr. Wiss. Bot.^ Jf. {1900), 2>P- 

 93- US, ph. 8, fign. 3; abs. in Bot. Centhl., 82 {1900), No. 2, j)])- 

 52-5Ji). — The previous investigations on the effect of diminished atmos- 

 pheric pressure on the germination and growth of plants are reviewed, 

 and an account given of experiments with Phaseolus vulgaris, Lejpidium 

 sativum, Satureia hortensis, Viclafaha, and Hortensia vulgare, in which 

 separate lots of seeds and plants were subjected to three different 

 atmospheric pressures for a considerable period of time. A special 

 form of apparatus was devised whereby the atmosphere could be 

 changed without affecting the pressures, which were kept constantly 

 at 570 to 580 mm., 170 to 180 mm., and 180 to 190 mm. As previ- 

 ously, it Avas found that under diminished atmospheric pressure the 

 growth of plants was more vigorous than under normal barometric 

 pressures, but that germination was slower and fewer seeds sprouted 



19607— No. 10 2 



