THE GOLGI MATERIAL 



79 



found expression in three hypotheses regarding the relation of the Golgi 

 material to components of plant cells. 



In 1910 Bensley treated root tips of Allium, Iris, and Lilium, and 

 the tapetum of Lilium, with fixing reagents (composed chiefly of neutral 

 formalin and potassium bichromate) which had been employed in the 

 investigation of the Golgi region in animal tissues. In very young cells 

 the vacuolar material had the form of a system of fine canals; in older 

 cells these "canaliculi" enlarged and gradually coalesced to form the 

 large vacuole (Fig. 4:1, A, B). Bensley succeeded in observing the various 

 stages in living cells. In view of the striking resemblance between the 

 vacuolar system and the Golgi canals of animal cells he ventured the sug- 

 gestion that the two are morphologically and physiologically equivalent. 

 This view has been supported, since, chiefly by Guilliermond." Guillier- 



* B - C 



Fig. 41. — A, B, cells from the root tip of Allium, showing development of cytoplasmic 

 canals into vacuoles. {After Bensley, 1910.) C, cells of the root of barley preserved by the 

 method of Golgi. (After Guilliermond and Mangenot, 1922.) 



mond and Mangenot (1922) treated barley roots with silver-impregnation 

 methods and obtained blackened networks corresponding in form with 

 the canalicuh observed by Bensley (Fig. 41, C). They, too, regarded 

 these stages of the vacuolar system as homologous with the Golgi 

 networks of animal cells. "^^ Further support for this view was seen by 

 Guilliermond in the work of Parat, who considered the vacuole system 

 (vacuome) to be a system common to both plants and animals. Zirkle 

 (1932) observes the similarity between the tannin-filled vacuome of 

 plant cells and the Golgi apparatus. Moreover, when such cells con- 

 taining only traces of tannin are fixed with the salts of heavy metals, 

 the insoluble tannates collect at the periphery of the vacuoles and give 

 the impregnation pictures so commonly reported in the Hterature. 



The second hypothesis is that proposed by Bowen,i^ who found in 

 plant cells subjected to osmic impregnation considerable numbers of 

 "osmiophiHc platelets." These were small flattened bodies in the cyto- 



"GuilUermond (1926, 1927, 1928, 1929a6e); see especially 1927 and 1929a. See 

 also Drew (1920), Laburu (1916), Sanchez (1922), Scott (1929), and Bose (1927, 1931). 



12 Long before this de Vries (1885) and Bokorny (1888) had blackened plant 

 vacuoles with osmium and with silver. The reactions seem to be due to the presence 

 of tannins; see Zirkle (1932). 



^^ (1926/1, 1927a6, 1928a, 1929a6c.) Gatenby (1928—1930) favors this hypothesis. 



