HOW ROOTS FIND THEIR WAY 



There are the most extraordinary coincidences in its 

 behaviour. It has the property of always doing exactly the 

 right thing in any emergency. 



It is of course intended to keep below the ground and in 

 the dark. So we find that if roots are uncovered, they will 

 turn away from the light and burrow into the earth again. 

 They avoid light just as a worm would do. 



Roots are of course intended to absorb or suck in water. 

 If there is a drain in the soil or a place where water collects, 

 the roots will grow towards that place. Very often they 

 form a dense spongy mass of fibres which may almost choke 

 the drain. Along a riverside one can often find great fibrous 

 masses of tree roots near the water. But how does the root 

 learn that the water is there and turn away from its original 

 track to find it ? It certainly does so ! 



Then again, Herr Lilienfeld has recently shown that roots 

 seem able to turn away from poisonous materials in the soil 

 and to seek out and grow towards valuable and nutritious 

 substances. He found that peas, beans, sunflower, and other 

 roots were very sensitive to different substances in the soil, 

 and were directly attracted by what was good for them and 

 turned aside from what was unwholesome. 



This property and the power of growing towards water 

 probably explain the mysterious sense of direction alluded 

 to above, for roots will take a line which has not been 

 exhausted by their neighbours.^ 



But of all these wonderful properties, the most remarkable 

 is the way in which roots find their way past stones and 

 other obstacles in the soil. They insinuate themselves into 



^ Lilienfeld, Beiliefte z. Botan. Centralhlatt, Band XIV. , abth 1, pp. 131- 

 212. The facts were denied by Newcombe and Rhodes, Bot. Gazette^ 

 36, 1904. 



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