A 





'% 



B t^ 



Ci 



D 



Fig. 2.4 — Pollen tube cultures treated and untreated. A. A metaphase of generative cell 

 of Lllium michiganensis without treatment. One per cent agar and 7 per cent sucrose, 

 stained with iron alum haemotoxylin. B. Anaphase, Polygonatum commutatum un- 

 treated. Stained with acetocarmine. C. Two microgametes and tube nucleus. D. Ar- 

 rested metaphase, c-pairs, caused by adding 0.01 per cent colchicine to culture media. 

 The duplications among c-pairs indicate polyploidy. There are 20 c-pairs but only 10 

 types for the entire group. Centromeric locus shown by incision along chromosomes. 

 Stained with acetocarmine. (Eigsti, 1940) 



