78 



Otis F. Cuhtis 



Diervilla sp., Populus nigra var. italica Du Roi, Spiraea Vanhouttei 

 Zabel, Forsyihia sp., three species of Salix, Iresine Herbstii Hook, f., and 

 Lycopersicum esculentum Mill. 



PART I. EFFECT OF INORGANIC COMPOUNDS ON ROOT GROWTH 

 EFFECT OF NUTRIENT SOLUTIONS 



In order to be able to follow more closely the development of the 

 roots, it was necessary to grow the cuttings in liquid media. To determine 

 whether a nutrient solution might increase root growth, various strengths 

 of Knop's and Crone's solutions were employed, as indicated in table 1. 

 Cuttings of Ligustrum ovalifolium were taken from two hedges which 

 had been growing under somewhat different conditions. The twigs 

 from one hedge (Column B in table 1) soon produced a strong growth 

 of tops, resulting in such a large increase in transpiration surface and 



TABLE 1. Effect of Nutrient Solutions on Root Growth in Woody Cuttings 



(Continuous treatment from November 21, 1914, to January 8, 1915. Ten twigs to a 



culture) 



Solution 



Average 



total 



length of 



roots per 



twig 



(millimeters) 



Number 

 of twigs 

 rooted 



Number 

 of twigs 

 rooted 



Crone's solution,* 0.5 per cent 



. 1 per cent 



0.01 per cent 



Knop's solution,! 0.5 per cent 



. 1 per cent 



0.01 per cent 



Modified Knop's solution, |0.5 per cent. . 

 . 1 per cent . . 

 0.01 per cent. 



"Tap water .' . 



Distilled water 



Dead 

 110±26.4 

 251±23.8 



Dead 



72±27.5 



260±28.5 



218±26.8 



203±37.5 



10 

 

 7 

 10 

 10 

 10 



Dead 

 Dead 



5 

 Dead 

 Dead 



4 

 Dead 

 Dead 



3 



3 



* Crone's solution contained salts in the following proportions: KNO3, 4; CaS04, 2: MgSOi, 2; 

 Fea(P04)!, 1; Cai(P0()2, 1. 



t Knop's solution contained salts in the following proportions: CaCNOs)!, 1 ; KNOs, 0.25; MgSOj, 0.25: 

 KH2POJ, 0.25; Fe2(P04)j, 0.06. 



, t The modified Knop's solution was similar to the preceding but contained five times the proportion 

 of iron phosphate. In both cases iron phosphate was used in place of iron chloride. 



