520 EXPERIMENT STATION KECORD. 



801). — Previous investigations of tlie authors (E. S. R., 21, p. 726) have shovpn 

 that formation of chlorophyll in green plants proceeds by definite stages and 

 that the phenomena are very complicated from a chemical point of view^. 



In the present paper they give the results of investigations in the formation 

 of chlorophyll in green plants. It is stated that this involves two stages. 

 The first includes the reactions by which the colorless leucophyll is converted 

 into colored chlorophyllogen without the direct action of light. The second 

 stage consists of chemi-^al or photochemical transformations by which chloro- 

 phyllogen is converted into chlorophyll itself. With the conifers and other 

 plants which become green in the dark the chlorophyllogen is acted on by 

 unknown chemical reagents, but with most green jilants the energy required 

 for the transformation of chlorophyllogen into chlorophyll is supplied by light. 



The part played by light has been found a complicated one. The maximal 

 accumulation of chlorophyll corresponds with an optimal light intensity, the 

 value of which varies with different species of plants. With excessive inten- 

 sity of light both etiolated and nonetiolated plants were found to turn green 

 more slowly, and the latter exhibited a kind of adaptation to strong light which 

 showed itself in accelerated accumulation of chlorophyll during the develop- 

 ment of the young plants. Chlorophyll accumulated by leaves developed in 

 daylight was found to possess considerable resistance to strong light. Brief 

 exposure of etiolated plants to strong sunlight retarded their subsequent green- 

 ing under the influence of diffused light. A well-deflned relation was found 

 to exist between chlorophyll and the yellow pigments accompanying it, and in 

 general the accumulation of each is influenced by the same factors. The pig- 

 ments are not combined chemically with chlorophyll, so that the destruction 

 of the latter in autumn leaves does not affect the yellow pigment. 



Formation of chlorophyll in plants, III, N. A. Mont£;verd6 and V. N. 

 LuBiMENKO (Izv. Imp. Akad. Xauk {Bui. Acad. Imp. Sci. St. P^tersh.), 6. ser., 

 No. 17 {1913), pp. 1007-1028, fig. 1; ahs. in Jour. Chem. 8oc. [London'], 106 

 {1914), -ZV'o. 616, I, pp. 2ff0, 24I). — A description is given of an improved appara- 

 tus for carrying out the spectro-colorimetric estimation of chlorophyll, xantho- 

 phyll, and carotin as described in a previous publication (E. S. R., 24, p. 718). 

 By means of the apparatus the amounts of the above pigments were determined 

 in fresh leaves of a considerable number of plants representing quite a range 

 of plant families. 



The authors also report investigations on the influence of various constitu- 

 ents of the ash of plants on the extent to which the leaves turn green, this 

 being measured by the proportion of chlorophyll present. Two series of ex- 

 periments were made, one with etiolated Luffa seedlings and the other with 

 etiolated wheat seedlings. With the first all the potassium salts used caused 

 marked increases in the amount of chlorophyll formed, while magnesium sul- 

 phate produced a slight increase. Calcium or magnesium nitrate brought about 

 a considerable decrease in chlorophyll formation, while sodium nitrate gave a 

 small decrease. The presence of sodium dihydrogen phosphate resulted in a 

 large increase. In the experiments with wheat seedlings magnesium sulphate, 

 potassium permanganate, or dihydrogen phosphate had no effect on the amount 

 of chlorophyll formed, while potassium nitrate had but a slight positive influence. 



Hydrocyanic acid in plants. — II, Its occurrence in the grasses of New 

 South Wales, J. M. Petbie {Proc. Linn. 80c. N. S. Wales, 38 {1913), pt. 4, pp. 

 624-638) .—In continuation of a previous paper (E. S. R., 28, p. 36) the author 

 reports on the occurrence of hydrocyanic acid in plants of New South Wales. 



The present paper is conflned to a study of grasses. In addition to its occur- 

 rence in si)ecies that are naturalized or cultivated in New South Wales, the 



