140 



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). 



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 sufficient water for transpiration and the 

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



