No. 1, July, 1920] PHYSIOLOGY 213 



WATER RELATIONS 



1412. Clakk, AbaBBLW. Seasonal variation in water content and In transpiration of leaves 

 of Fagus amerlcana, Hamamelis vlrginlana, and Quercus alba. Contrib. Bot. Lab. I'niv. 

 Pennsylvania 4: 106 143. SS fig. 1919.— The object of the re earch work recorded in tlii.s 

 paper was to determine seasonal variations in (eater rent cut and t ranspiration of leaves of the 

 beech, witch-hazel, and white oak. Results shou tii.it there ii no oonneotioo between irater 



content and transpiration, temperature and rclat ive bumidity, and t hat from 8 a.m. to . r > p.m., 

 there is practically no variation in water content, bu1 thai variations are regular and con- 

 stant for transpiration. The average water content v :er for HamameU rirginiana 

 than for Fagus americana and Quercus alba. It was found thai irater content is highest in the 

 spring, falls during the summer, and rises again in the fall, and thai transpiration is greatest 

 in the spring and lowest in the fall. — John W. Harshberger. 



1413. Coulter, J. M. Water conduction in trees and shrubs. (Rev. of : Pabmbb, J. Bkbt- 

 i. vmd. On the quantitative differences in the water-conductivity of the wood in trees and shrubs. 

 Proc. Roy. Soc. 90 B: 218-250. 1918. (See Bot. Absts. 2, Entries 306, 306).] Bot. Gaz. 67: 

 274-275. 1919. 



1414. Crocker, William. Transpiration. (Rev. of : Dogoar, B. M., and W. W. Bon-. 

 The effect of Bordeaux mixture on the rate of transpiration. Ann. Missouri Bot. Gard. 5: 153- 

 176. 1918. (See Bot. Absts. 1, Entry 688).] Bot. Gaz. 67: 277-278. 1919. 



1415. Crocker, William. Water movements in plants. (Rev. of : Re.vner, O. Versuche 

 zur Mechanik der Wasservorsorgung. Ber. Deutsch. Bot. Ges. 36: 172-179. 1918. (See 

 Bot. Absts. 2, Entry 549).] Bot. Gaz. 68: 72. 1919. 



1416. Hoagland, D. R., and A. W. Christie. The effect of several types of irrigation 

 water on the P H value and freezing point depression of various types of soils. Univ. California 

 I'ubl. Agric. Sci. 4: 141-157. 1919.— See Bot. Absts. 4, Entry 1654. 



MINERAL NUTRIENTS 



1417. Anonymous. Salt and the growth of coastland plants. Agric. News [Barbados] 

 18:321. 1919. 



1418. Bachmann, E. Wie verhalten sich Holz- und Rindenflechten belm Ubergang auf 

 Kalk? [The behavior of wood and tree lichens on a limestone substrate.] Ber. Deutsch. Bot. 

 Ges. 36: 528-539. 1918. — In the metabolism of endo- and epido-lithic lichens acids are secreted 

 which form soluble salts with the limestone. The secretion of the acid is most pronounced 

 on the surface of the gonida and the tips of the hyphae which penetrate the limestone forma- 

 tion rapidly. The nature of the acid is not known; however, it is very likely that it is car- 

 bonic acid which is liberated in the process of respiration of the organism. — Ernst Artschwager. 



1419. Breazale, J. F. Response of citrus seedlings in water cultures to salts and organic 

 extracts. Jour. Agric. Res. 18: 267-274. PI. 38-3$. 1919.— Seedlings of various citrus stocks, 

 including lemon, grapefruit, and several varieties of sweet oranges, showed no characteristic 

 differences in response in water cultures or in resistance to toxic solutions. — Very dilute or- 

 ganic extracts from upland peat (10 parts per million or more) stimulated root growth mark- 

 edly; but sodium nitrate or potassium chlorid, to which the stimulation might have been 

 attributed, proved not to be stimulants.— Calcium carbonate stimulated root growth and also 

 showed pronounced antagonistic action to toxic solutions of nitrates and ammonium sulphate. 

 —Very dilute peat extract ^20 parts per million) and calcium carbonate (solid phase present) 

 both protected seedlings against the toxins of distilled water. — Tolerance of seedlings for 

 alkaline salts is relatively high. The toxic limit for calcium hydrate was 100 to 120 parts per 

 million, for sodium hydrate 250 to 300 parts per million, sodium carbonate 550 to 600 parts per 



