380 



EXPERIMENT STATION RECORD. 



gives the iivera,iie iiieasnieineiits and weiglits for tlie different series of 

 cultures of seedlini^s and cuttinffs: 



Average of vultures of seedliuf/s aud cufthu/s. 



' In this series the sei^dlings were allowed to develop longer than in tlie other. 



In general the conclusion to be drawn from tlie experiments is that 

 in the seedlings of the species employed the growth of the roots and 

 shoots is largely independent of each other. In Zea mays the dry 

 weight of the roots at the end of the ex])eriinent was on the average 

 very much the same, whether the shoots had been repeatedly removed 

 or whether they had been allowed to remain, and the same is true of 

 the shoots with reference to the presence or absence of the roots. In 

 Vicia /aba the primary shoots of those plants whose roots were 

 removed could be readily observed at first to have developed more 

 vigorously than primary shoots of those plants whose roots were not 

 removed; whereas at the close of the exi)eriment the contrary was 

 the case, as is clearly shown by the difference between the gross weights 

 (see second group under Vicia faba in table). The roots of those seed- 

 lings from which the shoots were removed showed little or no diminu- 

 tion, and their average weight is rather greater than in the case of the 

 intact plants. 



The remarkable independence of the development of the roots was 

 apparent in other experiments made with the object of ascertaining to 

 what length the roots would grow in water when the primary shoot and 

 all subsequently developing shoots were removed. In Zea mays the 

 roots attained the maximum length of 630 mm., in Phasrolus multi/oriis' 

 a length of 0(51 mm., aud in Vicia faba a length of 718 mm. An experi- 

 ment was made with the seedlings of Vicia faha to ascertain the effect 

 of the removal of the roots, and although this experiment involved con- 

 siderable disturbance of the seedlings in consequence of repeated 

 digging u]) and rej)lanting, the growth of the shoots was not checked 

 until they had attained a maximum length of 4G5 mm. 



