628 EXPERIMENT STATION RECORD. 



Investigations in chlorophyll, R. Willstatter et al. (LieUg's Ann. Chem., 

 378 {11)10), Xo. 1, pp. 1-152, figs. S).— This consists of papers on the chemical 

 composition of chlorophyll, as follows: Comparative Investigations of Chloro- 

 phylls of Various Plants, R. Willstatter and A. Oppe ; Studies on Chlorophyllase, 

 R. Willstatter and A. Stoll ; and Studies on Phytol, R. Willstatter, E. W. Mayer, 

 and E. Iliini. 



The beginning of photosynthesis and the development of chlorophyll, 

 A. A. Irving (.Ann. Bot. [London], 24 {1910), No. 96, pp. 805-818, figs. 2, dgms. 

 S ) .—Experiments vpith seedlings of barley and Vicia falm to determine how 

 soon photosynthesis attains an appreciable magnitude with young leaves devel- 

 oped in light, or when etiolated leaves are exposed to light and turn green, 

 show that etiolated leaves do not possess any appreciable power of carrying out 

 photosynthesis of carbon dioxid, either when they are orange yellow or when 

 they have developed a large part of their green chlorophyll. When the power 

 of photosynthesis does appear, after the leaves have attained almost a full 

 green color, it develops very rapidly. 



The author believes that the first development of the function of photosyn- 

 thesis is not in any relation to the amount of chlorophyll produced, and that 

 the amount of chlorophyll is not a limiting factor to assimilation in the early 

 stages of assimilating organs. If this hypothesis is true, the author holds that 

 some other component part of the photosyuthetic machinery controls the be- 

 ginning of complete functional activity. 



A physiological study of the germination of Helianthus annuus, E. C. 

 Miller {Ann. Bot. [London], 24 {1910), A'o. <IG, pp. 693-^25, figs. 6, dgms. 18).— 

 A study was made of some of the changes taking place during the germination 

 of sunflower seed. 



During the first 3 days after planting the seed, the rudimentary roots and 

 hypocotyls reached a length of from 2.5 to 3.5 cm. The cotyledons at this time 

 had absorbed an amount of water equal to 50 per cent of their weight, while 

 the water in the hypocotyls and roots amounted to 90 per cent. During this 

 time the most intensive respiration in the development of the seedlings took 

 place, for at one end of this period the total weight of the seedlings amounted to 

 only i that of the resting seed. Five-sixths of the sugar content of the cotyle- 

 dons, 7 of the oil, and about i of the pi'otein had also disappeared. 



As the development of the seedlings advanced, the depletion of the reserves 

 in the cotyledons advanced from the point nearest the hypocotyl to the end 

 remote from it. The most marked change in the reserve material took place 

 between the time when the cotyledons were breaking through the ground and 

 the period when they were fully developed into foliage organs. 



The protein reserve during the progress of germination was broken up appar- 

 ently into ordinary cleavage products, which were transported to the roots and 

 hypocotyls, where they were used in the formation of new cell contents. 



The oil during the advance of the seedlings was in part broken down into free 

 fatty acids and glycerin. The marked increase in the amount of sugar during 

 the progress of development of the seedlings seems to make it certain that it 

 had its origin in the oil reserve. The cotyledons at no time contained any 

 appreciable amount of sugar, but it was present in abundance in the hypocotyls 

 at all stages. The amount of cellulose in the cotyledons remained constant, since 

 no new cells were formed. The sugar produced from the oil was used by the 

 plant for the formation of new cell walls in the growing parts. 



Whether this oil is transported from the cotyledons to the growing parts and 

 then transformed, or whether the transformation takes place in the cotyledons 

 previous to transportation, was not determined. 



