16 SOME RECENT RESEARCHES IN PLANT PHYSIOLOGY 



beet there is no reducing sugar in the root, whilst in others 

 such a sugar is present. This would be comparable to the 

 occurrence of maize grains with and without sugar. The 

 striking results obtained by Pearl and Bartlett (1911) upon 

 the segregation of such qualities as starch content, moisture 

 content, sugar content, ash content, nitrogen content, fat 

 content, etc., according to Mendelian laws of heredity, are 

 of great interest in this connection. Colin also found that 

 at the base of the petiole of the beet the ratio of reducing 

 sugar to sucrose was greater than unity, and he concludes 

 that the root receives both types of sugar, though only 

 sucrose is stored in quantity. Ruhland (1912) had 

 previously noticed this, and pointed out that in the beet 

 sugar is translocated mainly as invert sugar. 



Girard heads his last column, "To 100 of Glucose " 

 viz., hexoses not being aware of the possibility of the 

 existence of maltose in the leaf when starch is being dis- 

 solved during the night. The maltose present would tend 

 to make the value given for the reducing sugars too low, 

 for they were calculated as hexoses; and also to lower the 

 true value of the ratio of sucrose to hexoses, for the latter 

 now appear higher in amount owing to the erroneous 

 inclusion of maltose. These errors are, however, not of 

 great magnitude, for Strakosch has detected maltose only 

 in the petiole, though, as starch exists in small quantity in 

 the leaf, maltose must be present also; the presence of 

 maltase and diastase point to its existence there too. 



The results of Table VII. do not necessarily bear the 

 interpretation given to them by Girard, but fit in quite as 

 well with that of Strakosch. For it is obvious that, once 

 a certain concentration of glucose is reached, it will diffuse 

 into the veins, and may there result in an equilibrium mix- 

 ture of glucose and fructose. Combination of these hexoses 

 to form sucrose, and the translation of the latter to the 



