355 



extensive shelling of the blossoms will occur also with weather favorable 

 for blooming, if abundant nitrogen is present in the soil, or if virgin soil 

 with an abundant supply of nutrients and water is used for the cultivation 

 of grapes, when the luxuriant development of the vegetative organs limits 

 the further development of the sexual apparatus. 



In fact, Miiller gives examples of such cases and, at the same time, 

 states his experience, viz., that sometimes fertilization has helped over- 

 come the evil, and sometimes a long incision in the vine accomplishes the 

 same end. 



Miiller also ascribes to the same causes the appearance of seedless 

 grapes on the bunch, which, as a rule, is correlative with a partial shelling. 

 The seedless grapes are larger than the unpoUinated seeded ones which, at 

 times, remain on the bunch even until autumn. The seedless ones, however, 

 are not as large as normal, seed bearing grapes, although, like them, they 

 color and become sweet. Indeed, it is evident that they ripen earlier and 

 become sweeter than the grapes with matured seeds. 



Since the seed primordia in the seedless grapes do not seem much 

 larger than at the time of blossoming, it must be assumed that some dis- 

 turbance had taken place at that time. It is probable that, in such cases, 

 pollinization had taken place, but that either a temporary lack of suit- 

 able nutritive substances, or some other disturbance, prevented the further 

 development of the &gg cell. The stimulus, exercised by pollination on the 

 walls of the ovule cases is present and the grape consequently develops. 

 Since, however, it does not need to use up any of the nutritive substances 

 flowing towards it in maturing the seeds, this grape at first exceeds develop- 

 mentally the grapes containing seeds. Weighing seedless and seeded grapes 

 proves that the seed, in maturing, functions as a centre of attraction for 

 material. Miiller-Thurgau^ found that the weight of the fruit flesh of too 

 berries of Riesling was 



Seedless With i Seed With 2 Seeds Normal, with 4 Seeds 

 25.0 g 58.2 g 77.2 g 112. g 



As examples of the differences in the material development, the results 

 of an experiment by Miiller with Riesling may be cited here. 

 1000 berries on the 25th of September showed 



Seedless a weight of 208.9 g> sugar 10.63%, acid 18.2% 



Containing seeds ...a weight of 846.0 g, sugar 9.77%, acid 24.2% 

 On the 1 2th of October 



Seedless a weight of 231.0 g, sugar 14.7%, acid 11.0% 



Containing seeds ....a weight of 898.7 g, sugar 12.3%, acid 15.7% 



In regard to the effect of ringing, an experiment showed that the non- 

 ringed vines bore only unfertilized grapes, which fell soon, while the bear- 



1 Muller-Thurgrau, Einfluss der Kerne auf die Ausbilding des Fruchtfleisches bei 

 Traubenbeeren und Kernobst. II. Jahresbericht d. Versuchsstat. Wadensvveil 

 Zurich, 1893, p. 52. 



