OBLOBOPHTLL. 



51 



68. — With few exceptions chlorophyll is not found in cells 

 which are not exposed to the action of light.* When ordi- 

 nary green plants are removed for some time from the light, 

 the chlorophyll disappears from the chlorophyll-bodies, and 

 leaves them colorless. The same decoloration also takee 

 place when a plant is deprived of 

 iron as one of the constituents of 

 its food. The disappearance of 

 chlorophyll takes place normally in 

 higher, plants when the cells lose 

 their activity. In the case of leaf- 

 cells, upon the approach of autumn 

 the chlorophyll appears to be re- 

 moved to other portions of the 

 plant. 



(a) The cells of many Palmellacem, 

 and manv zoospores — p,.p., of (Bdogo- 

 nium and Vaucheria — furnish good ex- 

 amples of the coloration of nearly the 

 whole body of protoplasm. 



In Zygnemaths chlorophyll-bodies are 

 stellate, and in Spirogyni, spiral. 



In Yaueheria there are multitudes of 

 roundish or slightly angular chlorophyll- 

 bodies, which line the interior of the 

 large cells. The chlorophyll in the 

 leaves of many mosses may he easily 

 studied, even without making sections ; 

 in them the chlorophyll-bodies are round- 

 ish in outline. In the higher plants thin 

 cross-sections of the leaves afford the 

 best means for the examination of their 



chlorophyll-bodies, which are uniformly rogfm longata : the chloroplfyH 



.'^ ■ 1 1 i,. "^ IS lu spiral bands ; m the centre 



of a Simple rounded outline. of each cell is a nucleus, with 



(J)' Chlorophyll is' soluble in alcohol, '^'^gl'o'.^-Afterslchf P''°'°P'*™- 



ether, chloroform, benzine, essential and 



fatty oils, hydrochloric and sulphuric acids, and these may be used 



Fig 43.— Two filaments of Spi- 



* The cotyledons, of many Coniferae acquire a green color even in 

 total darkness. The embryo of PTioradendron is green in the unopened 

 seed,, and in certain seeds with thick coats, which are impervious to 

 light {e.g., in some GucurbttcicecE), a chlorophyll -bearing layer of cells 

 surrounds the embrya 



