STRUCTURE OF THE ROOT 



8; 



the growing hair, and the delicate cell-wall is lined by a thin film of 

 cytoplasm surrounding a central vacuole. A gummy softening of the 

 wall near the distal end leads to a most intimate connection with any 

 solid particle. The state of the root-hair in the soil is suggested by 

 Fig. 60. As the water in the soil is held in the form of surface films 



Fig. 6r. 



Seedling of Carpinus Betulus. h = 

 hypocotyl. c = cotyledons. hw=imiii- 

 root. s;c = lateral roots. r=root-hairs. 

 £=epicotyl. Z = foliage leaf. Natural 

 size. Strasburger. 



Fig. i>2. 

 Localisation of growth near to tlic root-tip 

 of Vicia Faba. In I. the root-tip has been 

 marked with 10 zones by lines 1 mm. apart. 

 In II. the same root after 22 hours. The lines 

 nearest the tip are now most separated owing 

 to the growth having been there most active. 

 (After Sachs, from Strasburger.) 



covering the several particles, the root can by its hairs tap those films, 

 however thin they may be in a dry soil. It is important further to 

 realise how numerous these root-hairs are. It has been estimated 

 that over two hundred of them may be borne on one square millimetre 

 of surface of the root of a Pea, while in other plants, for instance the 

 Maize, the number may be still higher. The effect of this is greatly 

 to increase the possible absorptive surface of the root. 



