526 EXPEBIMENT STAIJON RECOED. 



The influence of illumination on the formation and germinability of seeds, 

 R. Combes (Rev. G^i. Bot., 25 (WIS), A'o. 291, pp. iSO-i-'/i).— Following pre- 

 vious experiments with light influences on plants (E. S. R., 23, p. 723), the 

 author studied the effects on the developing seeds of several common weeds, 

 chosen at random, of illumination varying from full sunlight down to about 

 0.11 of that intensity. It was found (1) that while the number of fruits and 

 seeds in each and the proportion of well-formed seeds diminished continuously 

 with decrease of light, the volume and the weight of the well-formed seeds 

 increased to an optimum, after wtiich these also decreased; also (2) that the 

 percentage of seeds capable of germination increased in the same way to an 

 optimum illumination about the same as that just mentioned. 



Energy assimilated by plants cultivated under different illuminations, 

 E. Rose (Ann. Bel. Nat. Bot., 9. ser., 17 (1913), Nos. 1, pp. 64, figs. 3^; 2-li, pp. 

 63-110, figs. 12). — Employing the technique of Combes (see above), the author 

 can-ied out a series of studies on Pisum sativum, as a typical sun-loving plant, 

 and Teucrium scorodonia, representing the shade plants, regarding the influ- 

 ence of illumination in producing variations in the fresh and the dry weight 

 of plants, in the internal or external morphological characters of leaves or of 

 the entire plant, and in the chlorophyll concentration in the leaves. Studies on 

 energy of absorption comprehended (1) those with different leaves at the differ- 

 ent illuminations under which they developed, also (2) those with leaves under 

 the same illumination (direct sunlight) which had been developed under differ- 

 ent illuminations. To these are added an account of some complementary 

 experiments on the relations between leaf structure and energy assimilation. 



In the first type, at or about 0.75 of the normal illumination, the appearance 

 was unchanged but the dry weight decreased. In the second type, at the same 

 illumination, the appearance was normal, as was also the total di-y weight, but 

 there was a slight increase of dry weight in the aerial portions. At 0.67 of 

 normal illumination the normal appearance ceases in case of the sun-loving 

 type and the dry weight of the shade plant begins to decrease, and this con- 

 tinues, the normal appearance of the latter being maintained, however, down 

 to 0.33. The optimum illuminations for the leaves do not coincide with those 

 for the plants as a whole. Plants of the type best suited to sunlight showed 

 normally well-differentiated palisade cells, those of the shade-loving type a 

 loose texture. Assimilation proceeded more actively in strong light with the 

 former structure; in weaker light, with the latter. 



Plant cultures in colored lig'ht, H. Welten (Kosmos, 1913, No. 5, pp. 181- 

 185, figs. Jf). — As the result of expei'iments along the same lines as those of 

 Flammarion (E. S. R., 24, p. 720), the author found that several common plants 

 grown under colored light showed well-defined alterations of habit as regards 

 growth, proportion, and other qualities, which are discussed in connection with 

 the previous work referred to. 



Branch movements induced by changes of temperature, J. G. Grossen- 

 BACHEE (Science, n. ser., 38 (1913), No. 971, pp. 201-205). — This is a review of 

 the literature of branch movements and a report of observations which grew 

 out of a study of the crown rot of fruit trees. The literature quoted seems to 

 indicate a decided movement of branches of trees due to changes of temperature. 



Reversibility of the physiological processes in the ripening of seeds, S. L. 

 IvANOV (Zhur. Opytn. Agron. (Buss. Jour. Expt. Landw.), 14 (1913), No. 2, 

 pp. 64-^4, flff- i)- — It is stated that seeds of Linum vsitatissimum, Brassica 

 napus oleifcra, and Papaver sonmiferum, carefully collected and tested at sev- 

 eral stages of ripening, showed a respiration coefficient almost always less 

 than unity, a result contrasted with the findings of Godlewski (E. S. R., 27, p. 

 226) and Gerber. It is suggested that, while normal physiological processes 



