UPWARD TRANSPORT OF ORGANIC MATTER 35 



Sorbus, even when they were on defohated branches at 

 distances of from one to three meters from the nearest 

 leaves, if the phloem connections between fruits and leaves 

 were intact. Haller (1931) reports similar observations 

 with apples. In experiments, in 1931, Dr. MacDaniels 

 and I found that, though fruits on defoliated branches 

 appeared to grow as well as those on leafy branches, the 

 dry weight expressed as percentage of fresh weight was 

 distinctly less, and the fruits were less sweet. 



Miinch also reports a few results of interesting experi- 

 ments on the development of fruits when the fruits alone 

 or the fruits and leaves are kept in darkness. Such 

 experiments were carried out with Sorhus and Samhucus 

 with the parts in darkness, in some cases completely isolated 

 from leaves exposed to light by rings through the phloem, 

 in others the rings were so placed that the supply from 

 leaves must come through the phloem from below, while 

 in others the phloem connection was with leaves above. 

 The completely isolated parts in darkness failed to grow 

 and lost both leaves and fruits. Those connected by 

 phloem to leaves below grew normally or even better than 

 the checks or similar fruits in light, while, in the single 

 experiment reported, those fruits in darkness but receiving 

 food from above fell off. Those above the ring and in the 

 light made but little gain in dry weight. No mention is 

 made as to the number of leaves above the upper ring so 

 one cannot judge whether the poor growth of those fruits 

 in this region exposed to light, and the lack of growth of 

 similar fruits in darkness, as compared with the good 

 growth of fruits in the dark below the lower ring (see his 

 Fig. 29, p. 197), is or is not influenced by the total available 

 carbohydrate. The lessened nitrogen supply to the fruits 

 above the rings may also be a factor in the differences in 

 behavior. The data, however, are inadequate for drawing 

 comparisons between growth of fruits in darkness receiving 

 food from below as compared with those receiving food 

 from above. 



He also reinvestigated the question of movement of foods 

 to developing fruits of umbellifers (pp. 200-204). Stras- 



