1908] CURRENT LITERATURE 143 



wheat in the absence of oxygen, there is no increase in diastase, but the amount 

 formed in air and in pure O2 is equal. Increasing etherization of seedlings reduces 

 their growth and also the diastase. Traces of acid favor the production of secre- 

 tion diastase, but not of translocation diastase, while larger amounts hinder in 

 both. In general leaves that readily store starch have much diastase, while those 

 that contain sugar do not; but this is not uniformly true. Insolated starchy leaves 

 have more diastase than starch-free shade leaves of the same plant. No increase 

 of diastase on darkening pea leaves was obser\-able; but the author does not con- 

 sider the experiments with light satisfactory. — C. R. B. 



ITourishment of embryos. — Basing his study upon the conclusions, already well 

 established, that the endosperm is a live tissue which may affect ipso jaclo the 

 development of the embryo, Stingl reports the results" of his experiments to 

 determine how embryos were affected by other endosperm than their own. He 

 tested rye, barley, oats, and wheat reciprocally. No embryo freed from the endo- 

 sperm could be made to develop fully, nor even when replaced after the operation 

 did it develop as well as undisturbed ones. The four sorts were unequally affected. 

 Rye developed about equally with its owm and wheat endosperm ; not so well with 

 others. Wheat did better with r>'e endosperm than with its own, but not so well 

 with barley and oats. Barley flourished with wheat endosperm, grew less with its 

 own and r)-e, and least with oats. Oats embrj'os developed far more uniformly 

 with strange endosperms than the others did with oats endosperm, though it 

 did best with its own. One must suspect that some neglected factor is accountable 

 for the surprising conclusion that a plant may develop better with foreign endo- 

 sperm than witb its own.— C. R. B. 



Alpine plankton studies. — Shantz^^ has made a comparative study of Uie 

 plankton of the lakes of the plains and mountains near Pike's Peak. The different 

 alpine lakes studied differ somewhat largely from each other, but in general their 

 plankton is not abundant, and it is only in the fall that algae become dominant. 

 The plains lakes studied are artificial; their plankton is many times more abundant 

 than is that of the aloine lakes.— HzNiiy C. CoWixs. 



" Stingl, G., ExperimentelleStudieuberdieEniahrungvoapflanzUchenErabr>'o 



. Flora 97:3<58-33i- 3:907. 



'3 Sh.\ntz, H. L., a biological study of the lakes of the Pike's Peak regkm 

 iiminary report. Trans. Amer. Mic. Soc. 27:75-5^. 1907. 



