Chapter XIV 

 DEVELOPMENT OF THE VACUOLAR SYSTEM 



First stages in development:- The starting point of the recent 

 discoveries on the question of the development of the vacuolar sys- 

 tem was an observation made by us on the mode of formation of 

 anthocyanin pigment in teeth of leaflets from the rose bud. 

 We noticed that the pigment begins to form at the extremity of the 

 tooth. In examining a tooth from tip to base, all the phases in 



A ■^•M^sV 



4f'^ 



3 









ii^ ^>i 



^Mi!^# 





D 









^ ^ '•. -l^f ^ ..V- 



B"iG. 92. — Teeth of young, living rose leaflets containing anthocyanin pigment which 

 makes visible the vacuolar system developed from filamentous vacuoles which swell, anastomose 

 and fuse to form one large vacuole per cell. A, D, cells at tip; B, C. older cells. D, after Pensa. 



the formation of anthocyanin may be followed. Now, we ob- 

 served that in the youngest cells, namely, those at the tip, the 

 pigment appears as minute, numerous, filamentous elements very- 

 like the chondrioconts. These elements, taken all together, are 

 exactly like a chondriome. In the region nearer the base, these 

 elements seem to swell and be transformed gradually into small 

 vacuoles, which, by their fusion, finally form a single enormous 

 vacuole, occupying the major part of the cell and enclosing the 



