Cellular Growth 127 



simultaneous action upon division, enlargement, and differentiation 

 can conceivably take place when unicellulars are subjected to colchi- 

 cine. At least the processes may merge into each other so closely that 

 separating the actions becomes difficult or nearly impossible. 



Analysis and reports from widely different sources are brought to- 

 gether in this section that treats the microscopic, microchemical, and 

 gross anatomical changes in plants.^-Msi, so, 53, i5i, lo.-,, n., 1.35 



^.5-/; Microscopic and microcheyiiical data. The cell walls of 

 treated plants show different types of depositions which form stria- 

 tions.53 These are regularly observed for pollen tubes growing in 

 media containing colchicine. When stained, their distinction becomes 

 more clear. The submicroscopic structure of pollen tube walls has 

 not been studied. Data are accumulating from other sources that 

 point up the possibilities in this field. '^ 



Excellent photomicrographs showed that the cells of algae were 

 changed after growing in media carrying colchicine. ^'^ The newly 

 formed portions of cells in Oedogonium showed swelling and local 

 thickenings inside the cell (Fig. 4.7) . These were scattered without 

 regular order along the wall. Inner cell walls of Cladophora became 

 thicker than controls, showing that tmusual depositions had occurred 

 (Fig. 4.8) . Finally, the regular network characteristic for Hydro- 

 dictyon became distorted through swelling of the middle parts of 

 connecting cells (Fig. 4.9) . Also the points of contact were enlarged. 

 These three cases comparing treated and untreated cells leave no 

 doubt that colchicine exerts a strong influence during cellular dif- 

 ferentiation. ^'•'* 



The root hairs grown in cultures containing colchicine (0.25 to 

 0.5 )jer cent) offer a comparable source for analysis of cell wall 

 structure. Earlier we described the tumors that were formed on root 

 hairs. Now microscopic and microchemical study has correlated the 

 cell structure with the form taken under treatment. After the cell 

 walls were stained with chloro-zinc-iodide and these structures viewed 

 with ])olari/ed light, the irregularly deposited micelles were in dis- 

 tinct contrast to regular arrangements viewed in untreated root hairs. 

 Photomicrographs with polarized light are instructive for these com- 

 parisons. ^^ 



Pollen mother cells develojjing in colchicine (Carthamus tnic- 

 torius L.) were protoplasmically interconnected at the points where 

 cells touched each other.'"' Later, as pollen grains formed, one large 

 cell was composed of nimierous pollen grains within a connnon wall 

 (Fig. 4.10). Another developmental feature was the wall intrusion 

 which was essentially an excessive deposition of a callous-like material 

 on the inner wall (Fig. 1.10). The origin and nature of these de- 

 vcloiMuents are unknown, l)ul the change is an effect of colchicine. 



