AGRICULTURE ON THE PACIFIC SLOPE 



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cate tube^ closed at the outer end and opening directly 

 to the root at the other end. These little tubes or 

 pipes reach the tiny water reservoirs and draw away the 

 water from them. Since each soil particle is such a 

 reservoir, the root hairs must force their way in among 

 the particles and come into close touch with them in order 

 to get at the very thin film of water which each particle 

 holds on its surface. If you pull up the seeds, you will see 

 that the particles are so firmly attached to the root 

 hairs that they will be lifted up with the plant. The 

 root hair fits itself closely to the shape of the soil par- 

 ticle, and may even grow around it so as partly to in- 

 close it. The appearance of the root hair under the 

 microscope at times reminds one of a hand clasping the 

 soil particle firmly. 



How do the root hairs absorb water? It would not 

 be of much use for the root hairs to tap the reservoirs 

 if they could not take away the water. The soil par- 

 ticle holds fast to the water with a good deal of force, 

 which must be overcome by a stronger force before the 

 water can be drawn away. 



The root hairs take the water away from the particles 

 in a very simple way. If we float half of a seed cover 

 (e.g. of a squash seed) on water, the hollow side up, 

 and sprinkle a little dry sugar on it (figure 9), the sugar 

 will draw water through the cover. Sugar and other 

 substances in the seed help to draw in water through 

 the cover when the seed is placed in moist soil. In the 



