517 



to the older experiences. Andrlik and Mvsik\ on the ground of numerous 

 analyses, have come to the conclusion that the weight of the seed-bearing 

 tuber may sometimes be less than that of the normal tuber, at other times 

 greater. The root of the seed-bearing tuber is poorer in potassium, phos- 

 phoric acid and sulfuric acid as well as ammonium nitrate and amido- 

 nitrogen. The sap is purer. Of the organic substances formed by the 

 seed-bearing beet, the sugar content amounted to only 45 to 50 per cent. ; 

 in the normal beet 54 to 69 per cent. "The greater part of the organic sub- 

 stance, free from sugar, is in the pith. i. e., in the elements forming the solid 

 skeleton of the plant. * * * _" "The pith formation probably takes 

 place at the expense of the sugar." 



We perceive that the beet plant has changed its inbred method of 

 growth. Instead of storing, in the first year, only reserve substances in 

 the root and making use of them in the following year for the formation of 

 seed, it at once makes furthti use of the organic substances gained by the 

 leaf apparatus. 



This circumstance points to the fact that the normal process in the cul- 

 tivated beet, the uninterrupted formation of new leaves, has undergone 

 some disturbance. The growth has ceased for some time, rather the beet 

 has passed through a dormant period which would correspond to the winter 

 rest of a normally ripened tuber. The newly mobilized reserve material 

 is used here for the production of the inflorescence, just as in the normal 

 case, after the arrestment of growth. It is conceivable that the late frosts 

 may call forth such an arrestment. They will incite a greater formation of 

 seed stems, the later in the year they occur and the more the subsequent 

 weather favors inflorescence formation. If, howe\er, the weather, follow- 

 ing the frosty night, is especially favorable for the development of foliage, 

 the elongation of the axis, already begun, can stop and the development of 

 the root advance. In large sugar beet fields, as a rule, such seed-bearing 

 beets and similar transitional forms are found. This inclination to the set- 

 ting of seed can certainly be hereditary in the seed, possibly can be prepared 

 in the seed of normal beets, if not sufficiently matured, i. e., for example, if 

 harvested before it is ripe. 



Aderhold- has furnished experimental proof of the formation of seed- 

 bearing roots in Kohlrabi, as a result of frost action. He brought seedlings 

 in pots into a freezing chamber for 8 to 10 hours and then placed them out 

 with others which had been exposed to frost. In one experiment, he ob- 

 tained, for example, two seed-bearing roots from 18 untreated plants, while 

 from the same number of specimens which, for 10 hours in May, had been 

 exposed to a temperature of 2 to 6.5 degrees C. below zero, he had 7 seed- 

 bearing plants. In both cases some Kohlrabi plants later overcame the 

 impetus of frost action and formed a root body. 



1 Schossriibe unrl normale Riibe. Blatter f. d. Zuckerriibenbau 1905, No. 24, 

 p. 374. 



2 Aderhold, R. itber das Schiesson des KohlrabLs. Mitt. d. K. Biolog. Anst, 190(), 

 No. 2, p. 16. 



