138 EXPEKIMENT STATION RECORD. 



results are given of experiments on respiration, sugar storage, enzyms, etc., of 

 tubers and seeds wlien subjected to a temporary beating (wet or dry) at from 

 18 to 40° during tbeir dormant periods. 



The physiological significance of certain glucosids, T. Weevers {K. Akad. 

 Wetensch. Amsterdam, Proc. Sect. Set., 12 {11)09), pt. 1, pp. 193-201; abs. in 

 Bot. Centbl., 113 (1910), No. 11, pp. Ul, U2).—\ study was made of arbutin, 

 the glucosid which occurs in various species of Ericaceae. This glucosid is said 

 to play tbe part of a reserve material and is principally deposited in the leaves. 

 With tbe development of tbe young shoots the amount of arbutin diminishes 

 and that of hydrocjuinone increases for a time and diminishes as soon as assimi- 

 lation begins in tbe young leaves. 



In studies of different parts of the pear tree a glucosid was found which is 

 believed to be probably identical with arbutin, and an enzym isolated from the 

 young shoots rapidly hydroiyzed this glucosid into glucose and hydroquinone. 

 The glucosid was found to increase during the day and to diminish during the 

 night. During the summer it was deposited in the bark, to be used in the for- 

 mation of new shoots in tbe spring. 



From young shoots of Salix purpurea a salicin-splitting enzym, salicase, was 

 obtained, and an identical substance was isolated from Populus canadensis. 

 This is not considered identical with emulsin or amygdalase. 



From young shoots a mixture of enzyms was observed. It contained catalase 

 and two other oxidases, which differ from laccase and tyrosinase. From tbeir 

 typical reactions these have been named saligenolase and catecholase. 



Studies were made of salicin and populin isolated from shoots. Populiu was 

 found to be formed in lai'ge quantities in the normal shoots but wholly absent 

 in tbe etiolated ones. 



The examination of a number of species of Populus showed that they contain 

 a considerable quantity of saccharose, which plays the part of a reserve material. 



The presence and utility of boron in plants, H. Agulhon (Ann. Inst. Pas- 

 teur, 2Jt (1910), Xo. If, pp. 321-329). — This is a summary of work reported else- 

 where (E. S. R., 23, p. 230), in which tbe author shows that boron is a very 

 common constituent of plants and that it can be used by the higher plants in 

 promoting their growth. 



The action of useful and injurious stimulants on the respiration of plants, 

 N. N. IVANOv (Izv. Imp. Akad. Nank (Bui. Acad. Imp. Sci. St.-Petersb.), 6. ser., 

 1910, No. 7, pp. 571-581). — In continuation of previous investigations (E. S. R., 

 23, p. 230), the author has carried on experiments with wheat seedlings and with 

 etiolated plants of Vicia faba to determine the action of quinin bydrochlorid, 

 sodium selenite, potassium cyanid, phloro,glucin, arbutin, salicin, etc. 



In summing up the results of these experiments, as well as those previously 

 described, the author claims that living plants may be stimulated by nutritive 

 substances as well as those which prove injurious. The stimulation in both 

 cases results in increased respiration, and but little difference can be observed 

 whether the stimulant is a nutritive or a poisonous one. Phosphates, which 

 have been previously shown to have little or no influence on the respiration of 

 living plants, strongly stimulate the respiration when the plants have been 

 killed. Poisonous substances, however, strongly excite the respiration of living 

 plants, while they have little influence on the respiration of those that have been 

 killed. 



The effect of these different substances on the living protoplasm, as shown by 

 the respiration of plants, furnishes a means of distinguishing between useful 

 and injurious stimulants. 



