3° 



Table XII. Kxperiment showing the eftects of cutting primary roots 

 on the growth of secondary roots of Vicia Faba. 8 plants 

 used, I normal and 7 cut. All but six centimeters of the 

 primary roots were removed. Plants cultivated in water in 

 a moist chamber. Duration of experiment seven days. 



Average length of secondary roots in centimeters. 



Normal 1 1 



<^ut 35 



•Original length of roots 8-10 centimeters. 



In this experiment the pruning consisted in cutting all of the sec- 

 ondary roots on each plant except six, while the primary roots were 

 shortened to about six centimeters. This experiment lasted a number 

 of days and it will be observed that there was considerable increase 

 in the growth of the secondajy roots of the cut plants over that of 

 the normal. Numerous small tertiary roots occurred on the secon- 

 dary roots of the pruned plants, but these were not measured, there- 

 fore the whole correlative effect is not shown here. 

 Table XIII, Experiment showing the effects of cutting secondary 

 roots on the growth of primary roots of Vicia Faba. 1 2 

 plants used, six normal and six cut. Plants cultivated in 

 water under a bell glass. Growth of normal plants 

 equal loo^jr. 



Average daily growth in millimeter. 

 23456 



"Normal ii.o 13.6 5.2 4.4 2.8 i.o 0.6 



Cut 10.4 16.0 7.0 10.2 io.o 8.8 8.0 



Percentage ) Daily growth 95^^ 1 17'A i35'A 232^. 357-/^ 88ff 133^ 

 Cut to uncut ) Total growth 182^ 



Original length of roots 16 centemeters. 



Table XIY, Experiment showing the effects of cutting secondarj- 

 roots on the growth of primary roots of Vicia Faba. 10 

 plants used, one normal and nine cut plants. Plants culti- 

 vated in water in a moist chamber. Duration of experi- 

 ment 49 days. 



Average length of primary roots in centimeters. 



Normal 4S 



Cut 88 



'Original length of roots 8-10 centimeters. 



