156 



PLANT RELATIONS. 



power by which the work of the plant is carried on (see 

 §27). 



117. Summary of life-processes. — To summarize the nu- 

 tritive life-processes in green plants, therefore, photosyn- 

 thesis manufactures carbohydrates, 

 the materials used being carbon 

 dioxide and water, the work being 

 done by the chloroplast with the 

 aid of light ; the manufacture of 

 proteids uses these carbohydrates, 

 and also substances containing 

 nitrogen, sulphur, etc.; digestion 

 puts the insoluble carbohydrates 

 and the proteids into a soluble 

 form for transfer through the 

 plant ; assimilation converts this 

 food material into the living sub- 

 stance of the plant, protoplasm ; 

 respiration is the oxidizing of the 

 protoplasm which enables the 

 plant to work, oxygen being ab- 

 sorbed, and carbon dioxide and 

 water vapor being given off in 

 the process. 



118. Plants without chlorophyll. 

 — Eemembering the life-processes 

 described under green plants, it is 

 evident that plants without chlo- 

 rophyll cannot do the work of 

 photosynthesis. This means that 

 they cannot manufacture carbo- 

 hydrates, and that they must de- 

 pend upon other plants or animals for this important food. 

 Mushrooms, puff-balls, moulds, mildews, rusts, dodder, 

 corpse plants, beech drops, etc., may be taken as illustra- 

 tions of such plants. 



Fig. 147. The Southern pitcher 

 plant, showing the funnelform 

 and winged pitcher, and the 

 overarching hood with translu- 

 cent spots.— After Keener. 



