230 EXPERIMENT STATION EECORD. 



considerable inhibition of gi-owtb, wbile 2.5 parts of illuminating gas in the 

 same amount of air bad a similar effect. 



In commenting upon this investigation, tbe autbors believe tbat tbe use of 

 etiolated epicotyls of sweet peas would furnisb a delicate and accurate test 

 for traces of illuminating gas in greenhouses, where often a considerable injury 

 is met by the escaping of gas in quantities too small to detect by chemical 

 methods. 



The distribution and formation of respiratory chromogens in plants, 

 V. I. Palladin (Izi\ Imp. Akad. Nauk (Bui. Acucl. Imp. 8ci. St.-Petersb.) , G. 

 ser., 1908, No. 12, pp. 977-990; aJjs. in Zhiir. Opuitn. Agron. {Russ. Jour. Expt. 

 Landw.), 10 {1909), No. i, pp. 568, 569).— After describing a method of detect- 

 ing chromogens the author gives a report of the examination of 71 species of 

 plants, in 67 of which respiratory chromogens were found. They were absent 

 in Agaricus campestris, Helvella csculenta, wheat seedlings, and asparagus, birt 

 as other methods show their presence in all but the asparagus, it is believed 

 that only that plant may be considered an exception to the general rule of their 

 occurrence. 



The method for detecting chromogens consisted of boiling the plants in water, 

 after which they were comminuted. To the colorless solution obtained a 

 small quantity of peroxidase prepared from horse-radish was added, together 

 with a few drops of a weak solution of hydrogen peroxid. In the presence of 

 chromogens the liquid becomes red and then reddish brown. 



In considering the conditions for the formation of these chromogens the 

 author examined the influence of carbohydrates, aud found in experiments with 

 Rumex patienfia that supplying the plants with a 20 per cent solution of 

 saccharose increased the quantity of respiratory chromogen in the leaves. In 

 the superficial cells of the leaves wliich had been furnished saccharose an abun- 

 dant red pigment was observed, and this is held to be due to the fact that the 

 introduction of tbe sugar increased the respiration aud the oxidizing chromogens 

 did not need to be reduced. 



This same cause is believed to be the reason for the red and violet coloration 

 of shoots in many plants in the early spring. The occurrence of red pigment 

 in the fall is held to be due to the low temperature, which is accompanied by 

 oxidizing reactions. Under low temperature and the accompanying processes 

 of tbe dying of the leaves the chromogens are oxidized into pigments. 



Influence of phosphates on the respiration of plants, N. N. Ivanov (Isv. 

 Imp. Akad. Xaiik (Bill. Acad. Imp. Hci. .S7.-/¥/r/.s/>. ) , 6'. ser., 1910, No. 4, pp. 

 303-318, fig. 1). — Experiments were made with yeast, wheat seedlings, and 

 etiolated tips of broad beans which showed that 0.5 per cent of disodium phos- 

 phate depressed the fermentation of living yeast for a few hours, a 2 per cent 

 solution depressed the fermentation of living dry wheat germs. A 1 per cent 

 solution increased the evolution of carbon dioxid in dead wheat germs as well , 

 as those treated with acetone, and a 0.5 to 2 per cent solution stimulated the 

 evolution of carbon dioxid in dead wheat germs in the presence of a current of 

 hydrogen. The etiolated tips of the broad beans responded in the same manners 

 as wheat germs and yeast. Monopotassium phosphate was found to produce af-- 

 depressing effect in all cases. L. 



The role of boron in plants, H. Agulhon {Rcclicrclies sur la presence et le 

 rdle du bore chez les veg^taux. Thesis, Paris, 1910, pp. 163, j)ls. 6 ; abs. in Rev. 

 Vit., 83 (1910), No. 847, pp. 272, 273).— In another publication (see page 226) 

 an account is given of the catalytic action of boron when present in plants. In 

 the present abstract the role and action of this element when present in the 

 plant kingdom are discussed. 



