238 PHYSIOLOGY [Bot Absts., Vol. IV, 



1580. Anonymous. Measuring the temperature of leaves. Sci. Amer. 120: 365. 1919. 



1581. Bruett, E. M. Utility of blanching in food canning; effect of cold shock upon bac- 

 terial death rates. Jour. Indust. Eng. Chem. 11 : 37-39. 1919. — No evidence is found that heat 

 and cold shock increase the susceptibility of bacterial spores to heat, for the death rates of 

 such bacteria are not increased during a second heating beyond the death rates of "unshocked" 

 bacteria subjected to the same temperature. — H. Schmitz. 



1582. Burgess, J. L. Relation of varying degrees of heat to the viability of seeds. Bull. 

 North Carolina Dept. Agric. 40 6 : 9-11. 1919. — Record of experiments with seeds of garden 

 beans, cowpeas, soybeans, corn, oats, rye, and wheat, exposed at varying temperatures for 

 varying lengths of time to test influence on viability. — F. A. Wolf. 



1583. Chandler, W. H. The effect of cold winter of 1917-18 on the fruit industry. Trans. 

 Indiana Hortic. Soc. 1918: 91-103. 1 pi. 1919.— See Bot. Absts. 4, Entry 908. 



15S4. Child, C. M., and A. W. Bellamy. Physiological isolation by low temperature in 

 Bryophyllum and other plants. Science 50:362-365. 1919. — It has long been known that in 

 axiate plants a physiologically active growing tip more or less completely inhibits the devel- 

 opment of other growing tips or axes of the same plant. As regards the manner in which such 

 an effect of one part upon another may be produced, there are three possibilities: first, the 

 growing tip may inhibit by obtaining the greater proportion of nutritive material; second, the 

 inhibiting part may produce substances which are transported by the fluids of the plant to 

 other parts; and third, the activity of the inhibiting part may produce dynamic changes 

 which are conducted through the protoplasm and influence the physiological condition of other 

 parts. Serious objections to the first two explanations are cited. Extensive experiments 

 have been performed by the authors on Bryophyllum, Phaseolus multiflorus, Phasaeolus 

 macrocarpus, and Saxifraga sarmenlosa. In these experiments low temperature was used as 

 a block to the action of the growing tip upon other parts of the plants. In Bryophyllum 

 when a length of 2 to 3 cm. of the petiole is kept at a temperature of 2.5° to 3°, and the leaf 

 immersed in water, the notches will develop into plants. In experiments on varieties of 

 beans, the buds in the axils of the cotyledons could be induced to develop when a length of 

 2 to 3 cm. of the stem above the cotyledons was inclosed in the coil at 3°, 4° or even 5°C. 

 It appears at least highly probable that the inhibiting action of growing tip, leaf, or other 

 active region depends for its passage from point to point upon metabolically active proto- 

 plasm, rather than upon purely physical transportation through preformed channels. — A. H. 

 Chivers. 



1585. Greene, Laurenz. 1917-1918 winter injury to apple trees. Rept. Iowa State 

 Hortic. Soc. 53: 119-124. 2 pi. 1918.— See Bot. Absts. 4, Entry 926. 



1586. Hibbard, R. P. Temperature and crops. [Rev. of: Seely, D. A. (1) Relation 

 between temperature and crops. Monthly Weather Rev. 45: 354-359. 1917. (2) The length 

 of the growing season in Michigan. Michigan Acad. Sci. Rept. 20: 223-232. Fig. 22-25. 1918.] 

 Plant World 21 : 329-330. 1918. 



1587. Johnston, Earl S. An index of hardiness in peach buds. Amer. Jour. Bot. 6: 

 373-379. Fig. 1-2. 1919. — In attempting to find a criterion for determining the degree of 

 hardiness in the peach, the author has studied the moisture content in the fruit buds of two 

 varieties, the Elberta and the Greenboro, during the winter and early spring. He notes a 

 marked increase in water content in both varieties beginning about February 1, a condition 

 which he believes is related to the fact that peach fruit buds are always very "tender" in 

 early spring. No important differences were noted between trees receiving various fertilizer 

 I icatments or between those on high ground and those on low ground. The water content of 

 Elberta buds is consistently higher than that of Greensboro and this difference increases as the 

 season advances. Since the Elberta is considered less hardy than the Greensboro, these facts 

 are believed by the author to be significant as indicating that low water content is associated 

 with increased hardiness. — E. W. Snmolt. 



