90 THE PHYSIOLOGY OF PLANTS 



It is fi'om a dread of such consequences that the practice 

 has grown up of not pruning the roots at all in transplant- 

 ing, but of coiling them up spirally. This practice is further 

 strengthened by the observation that roots which have been 

 bent tend to produce numerous lateral roots immediately above 

 the bend. This observation holds good for seedlings at least, as 

 can easily be proved by growing them in water. When one 

 of the long roots reaches the bottom of the vessel in which the 

 plant is grown, it becomes bent, and lateral roots soon make 

 their appearance. 



Still the above-mentioned practice is to be condemned, as 

 we will surely do after inspecting the roots a few years after 

 transplantation. Generally the tap-root will be found again, 

 only spirally coiled, so that its apex, which bears the rootlets, 

 is closer to the surface. The older portions will not have pro- 

 duced any branches, and a number of those found near the apex 

 will never be so great as in the case of a properly pruned root. 

 We must also not forget that the nutrition of the plant cannot 

 be so favourable under these circumstance, as the water has a 

 longer course to take through the spirally coiled root. Now 

 the bending of any organ always retards the passage of the sap ; 

 the shorter and more direct, therefore, the passage is, the more 

 advantageous will it be to the plant. 



Older plants, even when well cultivated and nourished, are 

 always at a disadvantage as compared with younger ones, 

 because both the sap and the plastic substances have to pass 

 along much greater distances (sometimes no longer very pass- 

 able) before they reach the final goal, the growing points of 

 roots and branches. This causes the frequent dying off of the 

 tips of horizontal branches of old trees. 



As a matter of fact, therefore, the nutrition of plants with 

 bent roots is less favourable than that of plants with pruned 

 roots ; besides this, the transplanting of the former is always 

 more difficult. 



We must not close the chapter on the treatment of roots 

 without dwelling upon the important fact that fpeshly trans- 

 planted trees and shrubs are more sensitive than the untouched 

 ones. 



Generally speaking, the roots are more sensitive than the 



