I40 



Science of Plant Life 



erties of the soil and the air surrounding the plant ; also 

 light, gravity, and the influences of animals and other plants 

 (Fig. 78). 



■■■■■ v\ ^^^3K^-^ii^to#^^r^;^ 



GRAVITY 



w y y V V » V 

 Fig. 78. Diagram illustrating the environment of land plants. 



The soil factors. If a plant is to grow in a soil, the soil 

 must furnish it with sufhcient water for transpiration and the 

 manufacture of food. At the same time, the soil must not be 



