336 



EXPERIMENTS WITH PLANTS 



any plant by growing it with a reduced amount of 

 moisture. Make such experiments as you can on this 

 point. 



Study every case you can^ and, if possible, make 

 experiments, by growing the plants in pots (or plots) 

 and regulating the amount of water given them. 



191. Upper epidermis of Water-polygonum : UO from m leaf of a plant cultiviited under 

 dry conditions, (.b) from the first leaf produced by such a plant after being placed 

 in water, showing a larger number of stomata. 



It may seem surprising to find that many plants 

 which grow in damp places show the features de- 

 scribed above : such are plants growing in alkali soils, 

 or along the seashore where the water is brackish. The 

 explanation is that in these places there are substances 

 in the water which hinder its absorption by the roots 

 (see page 124). 



1 Plants subject to the drying action of strong winds show these features 

 excellently. 



