222 TRANSLOCATION IN PLANTS 



fall pass in appreciable quantities back to the stem, roots, 

 and soil. Calcium behaved peculiarly in that it continued 

 to increase until about June 20 and was not removed 

 before leaf fall. 



Failure to transport solutes through dead phloem tissues, 

 however, is not conclusive evidence that living cells take 

 an active part in the actual transport; for killing would 

 certainly coagulate some of the proteins that are abundant 

 in these tissues. Such coagulation would be expected to 

 prevent or retard movement of any sort through these 

 tissues, except perhaps diffusion. Czapek (1897) and 

 others, moreover, have found that treatments which reduce 

 certain forms of protoplasmic activity without killing the 

 cells may hinder food transport. He found that exposure 

 of petioles to chloroform which did not kill prevented, 

 however, the removal of starch from the blade. Deleano 

 (1911) also found chloroform to have a retarding effect 

 similar to that of killing but claimed that transport was 

 not completely stopped. As explained above, however, his 

 claim of transport through dead or anesthetized stems is 

 not well founded. Kruseman (1931) found treating the 

 petioles of Phaseolus leaves with chloroform, to interfere 

 with transport from the leaf. Schumacher (1933), how- 

 ever, found various anesthetics to have no effect on trans- 

 port of fluorescein, unless used in amounts sufficient to 

 cause injury. Possibly such injury occurred in the experi- 

 ments of Czapek and Deleano and recovery was due to 

 regeneration of new phloem cells. 



McCallum (1905) found that local etherization of a stem 

 would induce root development above the etherized part 

 when the etherized part was not killed, Moore and Willa- 

 man (1917) found that local fumigation of a stem of 

 tomato with hydrocyanic acid interfered with translocation 

 even when the stem was not killed. The delay of starch 

 removal from the upper part of the fumigated branch and 

 the development of axillary buds below this part may be 

 considered as evidence for an interference in translocation 

 either of carbohydrates, nitrogen, and such solutes or of 



