200 PHYSIOLOGY [Bot. Absts., Vol. VI, 



1348. Salter, Robert M., and T. C. McIlvaine. Effect of reaction of solution on ger- 

 mination of seeds and on growth of seedlings. Jour. Agric. Res. 19: 73-95. PI. 15. 1920. — 

 Using two modifications of Shive's best solutions, the author obtains data showing the impor- 

 tance of active acidity in the germination of seeds and in the growth of seedlings of wheat, soy- 

 beans, corn, alfalfa, and red clover. Germination of the seed of the five plants as compared 

 with the growth of the respective seedlings is found to be less sensitive to an acid reaction. 

 The optimum reaction for germination lies between P H 2.96 and P H 7.71, a slightly acid 

 reaction proving most favorable in all cases. In general, maximum growth of the seedlings 

 of all the plants occurs in the culture with an exponent of P H 5.94-5.16; death occurs at P H 

 2.16; and growth is conspicuously depressed at P H 7.71. During the growth of wheat seedlings, 

 there is a general tendency for the reaction of the culture solutions to shift to a point slightly 

 below neutrality, the value of change in reaction depending upon the stability of the solu- 

 tion employed. — R. W. Webb. 



1349. Vogg, L. Polygonum cuspidatum Sieboldund Zucc. Ein Studienversuch zur Pflan- 

 zenbiologie. [An experimental study in plant biology.] Ber. Naturw. Verein Schwaben u. 

 Neuberg 42: 175-183. 1919. — The author tabulates the results obtained by his study of the 

 growth of this Japanese Polygonum. For periods varying in successive years from about 4 

 weeks to 7 weeks he records the daily elongation of the stem, together with the temperature, 

 the barometric pressure, the moisture of the air, and the prevailing weather conditions. In 

 his last series of observations he records the growth of the branches, as well as that of the 

 stem. According to his deductions moist and warm weather are essential for rapid growth. 

 — A. W. Evans. 



MOVEMENTS OF GROWTH AND TURGOR CHANGES 



1350. Jennings, O. E. The paper mulberry an "artillery plant." Torreya 20: 52-53. 

 1920. — At Philadelphia on May 21, 1919, Broussonetia papyrifera Vent, was observed to be 

 throwing out pollen in a smoky cloud, the filament apparently straightening with sufficient 

 force to eject the pollen. In this respect the plant resembles the related Pilea serpyllifolia 

 Wedd.— J. C. Nelson. 



1351. Lorch, W. Die Torsionen der Laubmoosseata. [Torsions in the setae of mosses.] 

 Hedwigia 61: 40-91. 1919. — One hundred and four species of mosses were examined for tor- 

 sions of the setae. The results obtained embody both anatomical investigations and physi- 

 ological experiments. For the experimental part of the problem a specially designed appar- 

 atus was used which permitted a rapid and accurate determination of the angle of torsion. 

 Water content, age, and length of seta influenced greatly the degree and rapidity of the tor- 

 sion movement. The results obtained from 1153 experiments seem to show that the torsion 

 of the seta is a good specific character and that it could be made use of in taxonomic studies. 

 — Ernst Artschwager. 



GERMINATION, RENEWAL OF ACTIVITY 



1352. Sifton, H. B. Longevity of the seeds of cereals, clovers, and timothy. Amer. 

 Jour. Bot. 7: 243-251. 5 fig. 1920.— See Bot. Absts. 6, Entry 896. 



REGENERATION 



1353. Harvey, R. B. Relation of catalase, oxidase, and H+ concentration to the formation 

 of overgrowths. Amer. Jour. Bot. 7: 211-221. 2 fig. 1920.— The author has studied the osmot- 

 ic concentration of normal tissues and tumor tissues (produced by Bacterium tumefaciens) 

 in Ricinus and beet, by determining the freezing point depression through the use of a thermo- 

 couple. Little difference is noted between the two types of tissue, and the author believes 

 that the difference in osmotic concentration between them is so slight as to be quite unrelated 

 to tumor production. The determination of the freezing point of expressed juices as an indi- 



