ISO Botanical Microtechnique 



to obtain in quantity. Ten days after pollination the growing end 

 of the embryo has developed into a large sphere that can be found 

 in sections with adequate frecjuency (Fig. 15.7 c) . Collect develop- 

 ing fruits of various sizes, slice out a transverse median disk of ap- 

 proximately one-third depth of the fruit, and kill in Craf I. Dehydrate 

 and infiltrate with care. Section transversely, 10 yi for the earlier 

 stages, 15 to 18 |.i for larger embryos. As the seed coat of the maturing 

 seed hardens, sectioning becomes increasingly difficult; however, the 

 most important features of organogeny and the initiation of histogens 

 are evident before the seed coat becomes excessively hard. 



The legtmies may be tempting stdojects for embryology, but 

 the best known large-seeded species, as well as many small-seeded 

 species yield very few slides for the time expended. Lotus cornkulatus 

 is one of the most promising legumes. The long, straight o^"ar^ con- 

 tains many ovules in straight alignment, and sectioning is fairly pro- 

 ductive (Fig. 15.7 b) . 





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Fif;. 15.9— Transverse section of plumule in kernel of vellow dent corn. 30 (lavs after 

 pollination (ct)inlesy of Dr. Robert S. I'airchild) . 



