738 EXPERIMENT STATION RECORD. 



seems probable that such is the case. Preliminary experiments with apple 

 trees under like conditions led to similar results. 



The toxic property of bog water and bog soil, A. Dachnowski (Bot. Gas., 

 J,6 (1908), No. 2, pp. 130-1 'iS, figs. 6).— During an ecological study of a small 

 lake in Ohio, the author was led to give attention to the toxic character of bog 

 water and bog soils. The lake in question is characterized by two well-marked 

 plant zones, and investigations of water from each showed that it had marked 

 toxic properties. The water from the central zone was decidedly more toxic 

 than that from the other, but in both it could be corrected by aeration and by 

 the use of calcium carbonate and carbon black. 



Experiments were made on the germination of the gemma? of Marchantia 

 pfihjmorpha and afterwai'ds confirmed with water cultures of wheat, corn, 

 beans, and elm and buckeye seedlings. The plants grown in the bog soil ex- 

 tract and in untreated bog water showed decided stunting in root growth, while 

 the toi»s were more nearly alike. ^Marked differences in sensitiveness to the 

 toxic action were sho\An by the different plants, the beans proving very plastic. 

 The behavior of some of the plants was very similar to those grown in solutions 

 containing strychnin, atropin, and similar substances. 



The author believes that the inhibiting action of bog water and bog soils is 

 due to plant substances that are soluble and which are probably the products of 

 decomposition, plant excreta, etc. These substances by retarding oxidation, 

 decrease transpiration and result in stunted growth, or even in the death of 

 lilants. 



On plasmolysis, W. J. V. Osterhout {Bot. Gaz.,.'i6 ( 1908) , No. 1, pp. 53-r).5) . — 

 A discussion is given of the contraction of protoplasm within plant cells due to 

 the chemical action of salts as distinguished from true plasmolysis. It is 

 stated tliat the contraction of the protoplasm may often be prevented by the 

 addition of substances to the nutrient solutions. Contraction caused by sodium 

 chlorid may be prevented by the addition of a small quantity of calcium chlorid, 

 although the osmotic pressure of the solution is greatly increased. Water dis- 

 tilled from a metal still was found to produce apparent plasmolysis within a 

 few minutes, but this could be prevented by the addition of various inhibiting 

 substances. It is believed by the author that many of the contradictory results 

 attributed to i)lasninly«is are due to chemical action. 



The concentration of g'reen coloring matter in plants and photosynthesis, 

 W. LuBiMENKO (Rev. Gen. Bot., 20 (1908), Nos. 232, pp. 162-177, figs. 3; 233, 

 pp. 217-238, fig. 1; 23',, pp. 2.53-267, figs. 3; 235, pp. 285-297, pis. 2, fig. 1).— 

 Anatomical studies of leaves showed that the chloroplasts of shade-loving spe- 

 cies of plants are larger than those of plants accustomed to grow in full light. 

 The concentration of the chlorophyll was found to vary in different plants and 

 in the same plant with the age of the leaves. In old leaves a greater absorp- 

 tion of light is possible, due to a considerable concentration of the coloring 

 matter, and further it is probable that the limit of absorption for mature leaves 

 is not reached under the usual conditions of illumination. 



By means of spectroscopic analyses, the author was able to determine very 

 accurately the variation in chlorophyll in the leaves of different species of 

 plants at all stages of growth, and by a series of experiments he determined 

 that the photosynthesis of the plant depends not only on the mass of the 

 chloroplasts but on the concentration of the green coloring matter in the chlo- 

 rophyll grains. In studies made with 9 species of plants at temperatures vary- 

 ing from 20 to 38° C. and at 3 different degrees of natural illumination, it was 

 found that the maximum of photosynthesis does not coincide with the greatest 

 concentration of the coloring matter in chloroplasts. The maximum assimila- 



