and Laboratory Methods. 2241 



CURRENT BOTANICAL LITERATURE. 



CHARLES J. CHAMBERLAIN, University of Chicago. 



Books for Review and Separates of Papers on Botanical Subjects should be Sent to Charles J. 

 Chamberlain, University of Chicago, Chicago, lU. 



Shibata, K. Experimentelle Studien iiber die p^of Shibata records important ob- 



Entwickelung des Endosperms bei Mono- _ ^ 



tropa. (Vorliiufige Mittheilung) Biologisches servations upon the embryo-sac struc- 



Centralblatt 22 : 705-7 1 4, 1902. tures of Monotropa uniflora L. Most of 



the work was done with living material. The plants were kept in glass dishes 



with a little damp Sphagnum, and were kept covered with glass bell-jars. To 



prevent fertilization the stigma was cut off and the cut surface covered with 



paraffin. From time to time small pieces of the ovary with its ovules were 



removed, and here also the cut surfaces were covered with paraffin. When a 



sterilized knife is used and the cut surfaces are thus covered with paraffin, no 



damage is done by the operations, and a series of stages obtained from the same 



ovary may be studied in the living condition. 



Some of the results already obtained are as follows : The interval between 

 pollination and fertilization is dependent upon temperature. Under normal 

 conditions fertilization takes place about five days after pollination, and on the 

 same day, or the next day, from two to four cells are found in the endosperm. 

 After fertilization the egg elongates and breaks into the nearest endosperm cell. 

 Seed ripens in fifteen days after pollination. Light, atmospheric pressure, and 

 mechanical injury of the ovule or surrounding structures exert no influence upon 

 fertilization and subsequent phenomena. At 28° C. fertilization and subsequent 

 phenomena take place as at room temperature, and even at 30° C. the endosperm 

 nucleus can still divide, but at 31-32° C. fertilization can no longer take place 

 and various disturbances are seen in the embryo-sac. By lowering the temper- 

 ature the interval between pollination and fertilization is lengthened, and at 

 8-10° C. fertilization is prevented. 



The experiments show that the polar nuclei fuse even in the absence of 

 pollination, but the fusion is hastened by pollination even if fertilization be subse- 

 quently prevented by removing the portion of the style which contains the pollen 

 tubes. Normally, the polar nuclei fuse about five days after pollination, but 

 when pollination is prevented, the interval may be ten days or even three 

 weeks. 



The three small antipodal cells disintegrate after fertilization, but when fer- 

 tilization is artificially prevented they enlarge and become the most conspicuous 

 objects in the embryo-sac. Their growth is entirely checked at a temperature 

 of 30° C. 



Development of the endosperm can be induced experimentally in the absence 

 of fertilization, although in this case most of the ovules collapse. In the rest, 

 about 3-5 per cent., the development of endosperm begins about two weeks later 

 than when fertilization is allowed to occur. c. j. c. 



