522 EXPERIMENT STATION EECORD. 



fore, the above reaction takes place iu the leaf, not only would the proper condi- 

 tions for carbohydrate synthesis be established, but the nitrogen would also be 

 produced in the best form and the most available place for protein synthesis. 



The role of organic acids in the plant leaf and the relation of these sub- 

 stances to protein synthesis are under investigation. It has been found that 

 the hydroxy-acids, under the influence of ultraviolet light, are decomposed, 

 yielding carbon dioxid and aldehyde-like substances. These are believed to be 

 necessary in the further synthesis of compounds of importance to the organisms. 



Bhythm in plant development, G. Klebs (Sitsdei; Heiclell). AJcad. Wiss., 

 Math. IS'aturw. EL, 2 B {1911), Adhandl. 23, pp. 84; ahs. in Bot. Ccntbl., 119 

 {1912), No. 11, p. 426).— Continuing previous work by the author (E. S. R., 

 24, p. 141), an account is given of studies made on 40 living European plants 

 taken from their native environment to Java and there observed under control 

 conditions, in order to ascertain whether or not the tendency to vary between 

 periods of alternate growth and rest is inherent or dependent upon external 

 conditions. 



It was found that the most of these plants showed continued growth in the 

 new situation during the time when in Europe they would be at rest, but that a 

 somewhat marked resting period could be induced by lowering such life condi- 

 tions as temperature, moisture, nutrition, etc. This and further facts observed 

 led the investigator to advise caution in accepting the theory that an inner 

 periodicity exists, and to favor the view that periodicity depends very largely 

 upon climatic and nutritive conditions. 



A bibliography is appended. 



Transpiration in succulent plants, Miss E. M, Delf {Ann. Bot. [London'\, 

 26 (1912), No. 102, pp. ■i09-J,.',2, fig. i).— The author has made a study of trans- 

 piration in relation to the structure and habitat of succulent plants, particular 

 attention being given to the transpiring surface and water storing and conduct- 

 ing systems. 



It was found that the chief structural peculiarities of succulent plants are 

 connected with the transpiring surface and the storage of water. Summing up 

 the characteristics of the transpiring surface, the author found that succulent 

 plants show a varying amount of reduction in the leaf surface, and that this 

 may or may not be accompanied by arrangements which tend to diminish trans- 

 piration. Most succulent plants are characterized by the possession of definite 

 aqueous tissue; others have a great development of mesophyll in the leaves, 

 and then the innermost layers tend to function as storage cells for water. 



The author states that the peculiarities of succulent plants must be regarded 

 as adaptations to environment of real importance to the plant. They may be 

 produced during the lifetime of the individual, as in the development of addi- 

 tional mesophyll or storage tissue in a facultative halophyte, or they may ap- 

 pear as permanent characteristics, as in the case of plants that are found ex- 

 clusively in saline situations. 



The water relations of halophytes and sclerophylls, F. E. Lloyd {Carnegie 

 Inst. Wasliington Year Book, 10 {1911), pp. 61, 62). — The author gives a brief 

 summary of investigations to determine the absolute, relative, and cuticular 

 transpiration of a number of beach plants and of trees and shrubs from neigh- 

 boring slopes. A method was devised for observing the actual condition of 

 stomata on living leaves, and from the investigations tentative conclusions were 

 reached as follows: 



"(1) Little variation in the actual amount of water in the leaves was ob- 

 served, and the rate of loss was low in the cool air and high humidities of 

 the Carmel region in which the work was performed. 



