Lectiire 2, July 6, 1900. 



Plant Functions. 

 Normal plants if there are such ; typical plants, a better name. 

 Plant function includes nutrition, conduction, photosynthesis 

 conduction, storage, respiration, digestion, transpiration, secretion 

 and excretion, and movement. 



1. Nutritive function . The five most Important substances 

 absorbed are 0, COi,^H^O, organic and inorganic substances ; the 

 first two are taken in through the stomates, the others by the root- 

 hairs from the soil. Exceptions are found in submerged and desert 

 plants. The former take theirs in from the H^O through the skin, 

 the latter from the air. 



2. Conduction of raw material. and CO^ are in the leaves where 

 they can be used. The others must be carried through the tubes. 



3. Pho t o - s y nt h e s i s . Carbofa assimilation is a better term. 



00"^+ Hj^O = CH^O + 0^ or and oxygen. CH4,0 is a carbohydrate, 



Proteids introduce a new element N. Some N may pass through the 

 stomata but not much. 



4. nnnduction to place of use. Xylem e^lls carry water. Sieve 

 tubes of ploem carry the proteids. Sugar can be more" easily 

 carried since it passes through any part by osmosis. Starch can 

 only be carried as starch in the milky juice of plants as in 

 Euphoebia. The cross section of a pumpkin shows sieve tubes with 

 a viscous fluid. The development of the flower is complex, since 



