128 EXPEKIMENT STATION EECOKD. 



ume), and as to coloration in exposure to light, the author concludes that the 

 surprising stability of living chlorophyll is comprehensible only on the hypothe- 

 sis of a colloidal condition of that pigment. 



Investigations on the pigments in ch.romoleucites, V. Lubimenko {Compt. 

 Rend. Acad. Sci. [Paris'i, 158 (1914), No. 7, pp. 510-^13).— After calling atten- 

 tion to the change in chlorophyll in the pericarp of fruits, etc., which results 

 in the accumulation of yellow and red pigments in the chloroleucites, the author 

 gives an account of investigations as to the nature of the pigments which thus 

 replace chlorophyll. Oxygen is found necessary for the formation of these pig- 

 ments and while it is thought that there are probably a considerable number 

 of pigments which replace chlorophyll, they are all connected with lycopiu and 

 rhodoxauthiu, which are isomeric with carotin and xanthophyll. 



The role of yellow pigment in chloroplasts, D. Iwanowski (Ber. Deut. Bot. 

 GeseU., 31 {IdlJf), No. 10, pp. 6i.3-^i7).— Discussing the decomposing effects of 

 light on chlorophyll in solution, the author states that an increase in the pro- 

 pox-tiou of yellow pigment in alcoholic solutions is accompanied by an augmenta- 

 tion of stability in the chlorophyll content. From this he infers a protective 

 influence of the yellow pigment on the chlorophyll. 



Studies on the chemical process of anthocyanin pigment formation, R. 

 Combes (Ber. Deut. Bot. Gesell., 31 {1914), No. 10, pp. 570-578).— The author, 

 continuing to report on recent studies (E. S. R., 31, p. 35), summarizes sub.stan- 

 tially as follows : 



In certain cells of Ampclopsis liederacea greon growing cells showed a yellow- 

 ish brown substance very closely related to the anthocyanin pigment of red 

 leaves of the same plant and apparently transformable into that pigment by 

 reduction, a change which normally occurs on the checking of leaf gi'owth in 

 autumn. 



The experimental production of anthocyanin outside the leaf may, it is 

 claimed, be regarded as an accomplished fact, and leaf reddening may now be 

 considered as a process not of oxidation, but of reduction. The author expects 

 to piesent in a later communication some new evidence in this connection and a 

 new theory of leaf coloration based upon results of recent studies. 



Some conditions of formation and decomposition of starch, H. Lunde- 

 (iARDH {.lahrh. Wiss. Bot. [Piingsheim], 53 (191J,), No. 3, pp. 421-463).— The 

 author gives somewhat detailed results of studies made on transformation re- 

 lations observable under various conditions in seeds or shoots of plants repre- 

 senting a number of divergent groups, stating in conclusion that while few 

 entirely new facts have been brought out. it is safe to conclude that the simple 

 transformations starch <ri sugar and starch <=^oil can not be completely ex- 

 plained by the ordinary conception of reversibility. 



Physiology of latex in some rubber plants, F. Tobler {Ber. Deut. Bot. 

 GcseU., 31 {1914), ^'o. 10, pp. 617-620).— A study of Mascarenhasia elastica 

 showed that the sap from tapped trees was richer in caoutchouc in damp 

 weathei*, in leaves exposed to light, in young leaves, and in plants having in- 

 sufficient nitrogenous materials in their food supply. Sprouts arising at points 

 of ijijury to the trunk developed a greater degree of milkine.'^s in the sap than 

 did the main stem. 



In case of Manihot glaziovli a definite cycle of change in composition of the 

 sap exuded after tapping was noted. The caoutchouc content of growing parts 

 increased to a maximum near the point of most active growth. Partial gird- 

 ling was followed by thickening of sap in neighboring vessels in association 

 with an increase of bacteria therein. 



