CHAPTER SEVEN 



WATER AND THE PLANT 



The thirsty Earth soaks up the rain, 

 And drinks and gaps for drink again ; 

 The plants suck in the Earth, and are 

 With constant drinking fresh and fair. 



ABRAHAM COWLEY 



WATER forms a large part of a living plant. Lettuce 

 and various root crops, for example, are nine-tenths 

 water. The living matter of the cells is bathed in it, 

 and the whole structure of a plant, from the finest 

 rootlets to the most delicate tissues in the leaves, is 

 more or less filled with it. For good growth, garden 

 plants require large amounts of water, and the gardener 

 is interested in knowing how this may be provided for 

 them. 



How water is used by a plant. All the various mineral 

 substances needed by the plant can be taken in only 

 when they are dissolved in water. They are all obtained 

 from the water that is in the soil. Furthermore, every- 

 thing that is moved about inside the plant is carried 

 in water; only minerals and foods that are dissolved 

 in water can pass from one part of the plant to 

 another. 



Great quantities of water are evaporated (transpired) 

 from the leaves of plants. For every pound of dry 

 material in a mature plant, 500 pounds of water have 

 passed through that plant during its life. An acre of 

 thrifty vegetables in a single season uses 1000 tons of 

 water, which is equal to about 9 inches of rainfall over 

 the acre. A large sunflower in a single day of mid- 

 summer transpires more than a pint of water. 



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