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INTRODUCTION TO EMBRYOLOGY OF ANGIOSPERMS 



of the family. Dietrich (1924), who experimented some years later 

 with a larger variety of plants, found that Knop's solution with 2.5 

 to 5 per cent cane sugar and 1.5 per cent agar enabled prompt and 

 regular growth of embryos removed from immature seeds of several 

 species. He further observed that the cultured embryos tended to 

 skip the stages of development which had not been completed at the 

 time of excision and grew directly into seedlings. His efforts to 



Fig. 206. Apparatus and glassware used for preparing culture medium. (After 

 Randolph, 194-5.) 



cultivate embryos less than one-third of their mature size were, 

 however, unsuccessful. 



The work of Hannig, Stingl, and Dietrich, although of great 

 importance, seems to have been prompted more by curiosity than 

 any other reason, and it remained for Laibach (1925, 1929) to show 

 the possibilities of using this method to economic advantage. While 

 making some interspecific crosses in the genus Linum, he found 

 that the cross L. perenne X L. austriacum yielded fruits of approxi- 

 mately normal size but that the seeds were greatly shrunken and 



