1917] Hodgson: Abnormal Water Eelations in Citrus Trees 43 



narily picked from the tree, remains turgid for several months, it is 

 the common belief that the leaves draw the water out of the fruit when 

 the branch is severed from the tree. That this is exactly what does 

 occur, when the leaves are deprived of their normal water supply, is 

 shown by the following experiments: 



Experiment 1 Two shoots bearing small terminal oranges of 

 approximately the same size and having the same number of leaves 

 and approximately the same leaf area, were taken to the laboratory, 

 placed on the table and allowed to dry under similar conditions except 

 that in one case the fruit was severed from the stem. All cut surfaces 

 were sealed with vaseline. 



Within twelve hours a marked difference in appearance w r as 

 observed. The leaves on the shoot from which the orange was detached 

 were considerably shriveled while those on the other shoot remained 

 turgid and fresh. This difference became more pronounced as time 

 elapsed and in thirty hours a distinct difference in the appearance of 

 the fruits as well as leaves was visible. The detached fruit remained 

 firm and retained its dark green color and lustre while the attached 

 fruit was soft and flaccid and exhibited a dull green color without 

 lustre. This experiment was performed repeatedly with both oranges 

 and lemons with the same results. (See plate 12, fig. 1.) 



As all the cut surfaces were sealed, it seems clear that the leaves 

 on the shoot with fruit attached actually drew on its water content 

 and that it was this supply of water which enabled them to remain 

 alive and fresh long after the leaves on the other shoot had withered 

 and died. 



Experiment 2 Quantitative data on water content were desired 

 to substantiate the visible indications described in Experiment 1. 

 Therefore the latter was repeated several times and moisture determin- 

 ations on leaves and fruits were made at various periods. A repre- 

 sentative set of such determinations is given in table 2 : 



TABLE 2 



MOISTURE CONTENT DETERMINATIONS, TWENTY-FOUR HOURS AFTER BEGINNING 



OF EXPERIMENT 2 



Weight of Weight of Weight of Water con- 

 container and same when material in tent per 



Kind of material fresh material dry grams cent 

 in grams 



Orange detached from branch 23.40 21.670 2.665 185.0 



Orange attached to branch 23.585 22.367 2.075 142.1 



Leaves from branch (21.831 21.805 .181 



with fruit removed |22.045 22.010 .170 21.4 avg. 



Leaves from branch j 21.345 21.275 .175 



with fruit attached |20.604 20.477 .284 73.7 avg. 



