8 FERTILIZERS 



to growth. Less water can come into it ; therefore, 

 less water and less food enter the plant. Less sun- 

 light can act on it, and all of the activities of the 

 plant are so reduced that the result is a small crop 

 of undersized fruit. Consequently, a good leaf is 

 essential to the best results. 



BARK. 



6. What has been said of the function of leaves is 

 true, to some extent, of green bark. Old, corky bark 

 may be regarded as the armor or shield to the cam- 

 bium layer. But young, tender bark can carry on 

 the process of respiration of carbon and oxygen, and 

 of transpiration of moisture, and to that extent the 

 transformation of the sap and plant food. Although 

 these activities in bark are very limited, they are 

 sufficient to continue the life of the tree should it 

 ever become defoliated for purposes of transplanting 

 or on account of disease or frost. Under the young 

 bark's continued activity new leaves may start, 

 until finally the plant renews its full health and 

 vigor. 



ROOTS. 



7. The distribution of plant food throughout the 

 soil influences directly, and, with water, the entire 

 development of the root. The absorptive power of 

 the root is in the young, tender rootlets or fibres, 

 by means of root hairs invisible to the eye. These 

 root hairs are distributed along the length of the 

 tender, growing fibre. The end of the fibre has a cap 

 which protects it as it develops and crowds its way 

 between the smallest soil particles. The very tips of 

 roots and fibres cannot absorb moisture or food. 



