CHAPTER VII. 



WATERWAYS 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 consisting of a jelly-like but 

 living substance called protoplasm surrounded by a thin wall. 

 Each cell absorbs water, which makes it 

 firm. This water holds salts dissolved in 

 it, which are obtained from the soil. 

 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. 



Ex. 13. 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 remainder of the syrup 

 dissolve sugar until no more can be taken. Sink the cell into this thick 

 syrup and set aside for another day. What has happened ? The thick 

 syrup has drawn the water out. The water within has passed in the 



1 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. 



57 



Fig. 66. — A bottle 

 "cell". I. Bottlecon- 

 taining sugar solution; 

 II. the bottle after re- 

 maining in the cup of 

 fresh water. 



