K 



^1^ 



B 



1 _ -■■^%:^*' I 



W« Vv 





•ss 



■?it 





isil*^' 





Fig. 4.3— Pollen mother cells of Tradescantia palludosa. Confrol and treated cultures. A. 

 Untreated microspore. B. Univalents induced by colchicine. C. Desynaptic metaphases, 

 four days after treatment was made. D. Diploid microspore from a treatment that be- 

 came effective at the second meiotic division. E. Octoploid microspore 21 days after 

 treatment; time of treatment 48 hours, then time allowed for recovery, two meiotic di- 

 visions inhibited, and one premeiotic c-mitosis. F. Tetraploid microspore, 12 days after 

 treatment. G. Hexaploid microspore, an unequal division that is similar to a distributed 

 c-mitosis. (After Walker) 



