CELOROPHTLL. 



51 



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

 Tvhich 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 

 Jeaves 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. I 



(a) The cells of many PalmeUaeem, 

 rand manv zoospores — e.g., of CEdogo- 

 nium and Vaucheria — furnish good ex- 

 amples of the coloration of nearly the 

 whole body of protoplasm. 



In Zygnema the chlorophyll-bodies are 

 •stellate, and in Spirogyra, spiral. 



In Vaucheria there are multitudes of 

 roundish or slightly angular chlorophyll- 

 hodiea, which line the interior of the 

 large cells. The chlorophyll in the 

 leaves of many mosses may be 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 . pig 42._Two filaments of Spi- 

 chlorophyll-bodies, which are uniformly W™ ?^7gl« L^iaT/c^nfre 

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



. (6) Chlorophyll is soluble in alcohol, 'j^'^soH^fter'^lchf P™'"?'*™- 

 ether, chloroform, benzine, essential and 

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



* 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 («. g., In some Cucurbitaeece), a chlorophyll-bearing layer of cells 

 {surrounds the embryo. 



