626 EXPERIMENT STATION RECORD. 



nioability is essentially regulable not alone in the organs whicti are in relation 

 with the external inediiini, but si ill more within the comj)onent tissues. 



Evaporation and plant succession in southeastern Washington and adja- 

 cent Idaho, J. E. WjiAVKB {I'lant World, 17 {IHIJ,). Xo. 10. pp. .>l.i-.i'.>J,. flijs. 

 10). — A preliminary study, as detailed, of the differences of rates of evapora- 

 tion in the various plant formations and associations in this region is con- 

 sidered to show that these differences are sufficient to be important factors 

 in causing succession, at least through the earlier stages, where light values 

 are usually high. 



The effects of acid and alkaline solutions upon the water relation and the 

 metabolism of plants, A. Dacunowski {Anier. Jour. Hot., t {V,)lJf), So. 8, pp. 

 -'il2--'i3D, //f/.s. Ji). — In extension of i)revious work (E. S. R., 31. p. G25), experi- 

 ments are detailed as carried out to ascertain the possible importance of hydro- 

 lytic reactions in determining the amount of water absorbed and retained by 

 plants during germination and growth, these experiments employing corn and 

 bean seeds and tomato cuttings. 



The results, which are given at length, are thought to justify the general con- 

 clusion that the variation in the water content of seeds can not be brought 

 about solely through the concentration of acids and alkalis within the cells and 

 tissues, and that the alterations here noted may be explainable on the hypothesis 

 that hydrolytic changes are taking place whereby the water content in the seeds 

 varies more and more as complete hydrolysis is approached. It is suggested 

 that this work may aid in developing further the conception of antagonistic rela- 

 tions among salts, 



A bibliography is appended. 



Root habits of desert plants and the reaction of roots to soil temperature, 

 W, A. Cannon {Ahs. in Science, n. ser., Jfl {1915). No. lOJfS, pp. 113. II-',)-— 

 According to the author there are three well-marked types of roots of desert 

 perennials, those which never penetrate the ground deeply, tho.se which pene- 

 trate the ground but have few or no roots near the surface, and those which 

 are intermediate between these extreme forms. The relation of these different 

 types of root systems to the temperature of the soils is discussed. It is thought 

 that differences in temperature response, coupled with differences in soil tem- 

 perature, are the definitive factors which bring about the characteristic dis- 

 tribution in the soil of the roots of the species studied. 



Electrolytic determination of exosniosis from the roots of anesthetized 

 plants, M. C. Merrill {Ahs. in Science, n. ser., Jfl (1915), No. lO^S. p. 176). — 

 The author subjected growing plants of Pisum sativum to the influence of 

 illuminating gas and ether vapor to determine their effect on exosmosis from 

 the roots. 



Where the roots were exposed directly to the anesthetics the resulting exos- 

 mosis was more rapid than where the roots were kept in water during the 

 exposure. In the former case the root turgor decreased greatly, while in the 

 latter case the tops were affected but the roots remained normal in appearance 

 even though the exosmosis was abundant, thus indicating a disappearance of 

 mineral nutrients from the tops. With older plants the increased conductivity 

 was less than with younger plants, indicating a greater resistance to the anes- 

 thetics. 



The germination of belladonna seed, A. F. Sievers (Amcr. Jour. Pharm., 86 

 (191J,), No. 11, pp. 1,83-505, figs. 10). — ^Detailing studies as carried out, the 

 author states that freezing accelerates germination, that seed size shows no 

 influence (but high specific gravity indicates high germinability). that color has 

 no meaning in this connection, and that sulphuric acid treatment has no great 



