THE ROOTS OF PLANTS. 



CHAPTER XXXV. 



THE FUNCTIONS OF THE ROOTS. 



The roots of plants perform two offices; one is to support 

 the plant in the soil; the other is to gather food and convey 

 it into the plant. In fact the roots of plants are the mouths 

 by which their food is introduced into the circulation. 



The roots possess a power of selecting suitable matter fromi 

 the soil for the nutrition of the plant; but whether or not 

 they have the ability, or exercise any power, to prepare the 

 food for assimilation, is not certainly determined. There 

 is reason to believe, however, that to some extent the roots 

 not only select suitable nutriment from the soil but also pre- 

 pare such food as may be required from the imperfect ma- 

 terials which exist in the soil. Roots seem to have the pow- 

 er of rejecting unsuitable or unnecessary matter which may 

 have been absorbed, and has answered its purpose; but for 

 which there is no further use. All these functions have a 

 most intimate relation to the growth of crops, and hence 

 furnish a most important subject for the careful study of 

 the farmer. 



The absorptive function of the roots is exercised by ex- 

 ceedingly numerous and very fine hair like fibers, which 

 are attached to the ultimate thread like ramifications of the 

 visible roots. From the difficulty of separating these mi- 

 nute and exceedingly weak rootlets from the soil in which 

 they are enveloped, and which they grasp firmly, it is diffi- 

 cult to examine closely the form of the root to its smallest 

 fiber; but a very good example may be obtained by start- 

 ing a seed to grow in fine sand in a small pot, and watering 

 it with weak manure water until the sand is filled with the 

 roots. The ball of sand is then washed from the roots, and 

 the very large comparative growth of them as compared 

 with the small size of the plants, and their peculiar structure 



