80 PHYSIOLOGY [BoT. Absts., Vol. IX, 



GERMINATION, RENEWAL OF ACTIVITY 



524. Welton, F. A. Longevity of seeds. Monthly Bull. Ohio Agric. Exp. Sta. 6: 18- 

 24. 1921. — Brief reference is made to work done by Vilmorin, Haberlandt, and Sifton. 

 Factors affecting the longevity of seed are discussed and reference is made to hard seed. The 

 report in tabular form shows the per cent of viability of the seed of cereals, other grasses, and 

 a few vegetables grown on the station farm at Wooster, Ohio, extending over a period of 12 

 years. — R. C. Thomas. 



TEMPERATURE RELATIONS 



525. Walster, H. L. Formative effect of high and low temperatures upon the growth of 

 barley: A chemical correlation. Bot. Gaz. 69: 97-126. 18 fig. 1920. — The usual view that 

 the optimum germination temperature is that which most quickly permits the emergence of 

 the radicle and plumule is not accepted, except for the germination function taken by itself. 

 A high temperature and a high nitrogen supply at the time of germination so shift the equi- 

 librium toward excessive vegetation as to prevent the normal tendency toward reproduction. 

 The tendency toward excessive vegetation inaugurated by an excess of nitrate nitrogen ac- 

 companying germination and early development at high temperatures cannot be counteracted 

 by the addition of phosphorus or potassium salts. A chemical analysis of the leaf reveals 

 (1) that "high heat supply + high nitrogen supply in nutrient solution = high soluble nitrogen 

 in leaf + low soluble carbohydrate = excessive vegetation and little culm formation," and (2) 

 that "low heat supply + high nitrogen supply in nutrient solution = low soluble nitrogen 

 in leaf + high soluble carbohydrate = normal vegetation and normal culm formation."—^ 

 H. C. Cowles. 



RADIANT ENERGY RELATIONS 



526. WuRMSER, Rene. L'action des radiations de differentes longuers d'onde sur I'as- 

 similation chlorophyllienne. [The effect of rays of different wave length on chlorophyll assimi- 

 lation.] Compt. Rend. Acad. Sci. Paris 171: 820-822. 1920.— The work is carried out with 

 a new method based on the principles outlined by Loeb and Osterhout. Phenolphthalein 

 was used as an indicator, and experiments were performed with Ulva lactuca and Rhodytnenia 

 palmata. The rate of assimilation in the red, green, and blue respectively was found to be 

 100, 24, and 80 for Ulva, and 100, 50, and 18 for Rhodymenia. It thus appears that the red 

 pigment of the Rhodophyceae makes possible the use of green light in photosynthesis. — 

 C. H. Farr. 



527. WuRMSER, Rene. L'action de la lumiere sur la chlorophylle coUoidale en presence 

 de stabilisateurs. [The action of light upon colloidal chlorophyll in the presence of stabilizers.] 

 Compt. Rend. Soc. Biol. 83: 437-438. 1920.— While chlorophyll is destroyed by light very 

 rapidly when in solution, yet in the plant it is destroyed slowly. By mixing a solution of 

 chlorophyll prepared by the method of Willstiitter and StoU with various colloids this destruc- 

 tive action of light has been greatly retarded, a gelatin solution being the most effective of 

 those tried (gelatin, egg albumin, gum arable, and starch paste). — E. A. Bessey. 



TOXIC AGENTS 



528. MifeoE, E. Action de la chloropicrine sur la faculte germinative des graines. [The 

 effect of chloropicrine on the germinating ability of seeds.] Compt. Rend. Acad. Sci. Paris 

 172: 170-173. 1921. — Chloropicrine is found to interfere with the germination of some seeds 

 while not affecting others at ordinary concentrations. Flax is not affected at 15 cc. per cubic 

 meter, but is affected at 50 cc. concentration. Legumes in general are resistant, whereas 

 grasses are sensitive to the gas. About 15-20 cc. per cubic meter is recommended as an 

 insecticide, being used for a period of 24 hours without much injury to any seed. — C. H . Farr. 



