CHAPTER VII 



WATER WAYS IN PLANTS 



How Roots take in Water. — In Chapter IV. we read of the 

 water passing from the soil into the roots and thence to the 

 leaves. It is now time to see how this is done. 



Each root-hair is a small cell surrounded by a thin mass of 

 a jelly-like but living substance called protoplasm. Each 

 cell absorbs water, which makes it firm. This water holds salts 

 dissolved in it, and is called sap. When a plant is supplied 

 with water it passes through the walls of the root-hairs and on 

 into other cells ; for the whole plant is 

 made up of millions of tiny cells. To see 

 how this is done, let us try an experiment. 



A Bottle Cell. — Take a small wide- 

 necked bottle and fill with syrup made 

 by dissolving a teaspoonful of sugar in 

 half a cup of water. Tie over the mouth 

 a piece of membrane.^ 



Be careful that the solution quite fills 

 the bottle before covering. Sink the bottle 

 in a cup of fresh water and set aside 

 until the next day. The membrane now 

 bulges over the mouth. Water has been 

 drawn into the "cell." Into the re- 

 mainder of the syrup dissolve sugar until 

 no more can be taken. Sink the cell into this thick syrup 



Fig. 66. — A bottle "cell." 

 I, Bottle containing 

 sugar solution ; II. the 

 bottle after remaining 

 in the cup of fresh 

 water. 



' Obtain a bladder at the butcher's shop. Have the butcher remove 

 the surplus meat and inflate it. When a piece is required, cut it the 

 required size and soak it. It will become thick, but can be separated into 

 layers. Botanical supply companies supply diffusion cells for the purpose, 

 which are neater and more convenient, and should be obtained. 



