PLAKT LIFE ON THE FAKM. 



The effects will be first and most especially olrvious at 

 the point of injury, and at the growing points, where the 

 life-functions happen to be going on most vigorously at 

 the time. Thus, if the young shoots and young leaves 

 are in full activity at the time when root-mischief occurs, 

 they will the soonest show the effect of cutting off sup- 

 plies they will wither and droop. If the process is slow 

 and gradual, the leaves will become emptied of their 

 contents, their chlorophyll will change color, the plant 

 will assume a sickly yellow look very characteristic to 

 the practiced eye. The older portions of the plant, with 

 their reserve stores of water and food, may not immedi- 

 ately suffer ; and it is from them that the materials 

 requisite for any effort at repair and reorganization must, 

 if it be possible, be made. Thus a plant may grow for 

 some time after injury, and then suddenly flag because 

 its reserve supplies are at length exhausted. It follows 

 from this that death from starvation as a consequence 

 of root-mischief is not generally a sudden, but more often 

 a gradual process, the length of time of course varying 

 according to the nature of the mischief, and specially 

 according to the nature and condition of the plant. 



Death beginning at the Leaf, This may be appre- 

 ciated from what has been before said as to the functions 

 of the leaf. The leaf is an organ of nutrition, of respira- 

 tion, and transpiration; if its functions are sufficiently in- 

 terfered with, death will result, either from inanition or 

 from suffocation, or from both combined. The power of 

 resistance that a leaf has may be inferred from its 

 structure. A thick, fleshy leaf, with layer after layer of 

 chlorophyll-containing cells, with abundance of pores 

 and a thick skin, is obviously better able to resist in- 

 jurious agencies than a thin leaf whose delicate texture 

 speedily withers and falls a prey to adverse circum- 

 stances. 



