No. 449-1 



STUDIES ON THE PLANT CELL. 



377 



Botrydium), in the Rhodophyceae {e. g. Polysiphonia) and also 

 in the pahsade cells of leaves. Chloroplasts after expo.surc to 

 light generally contain starch but in some plants thi.s sul)stam c 

 IS never formed {e. g. Vaucheria, tig. 2 A i), the hrsl viMl)k' 

 products of photosynthesis being other substances more ot the 

 nature of oil It is not known whether the starch gram in the 



chloroplast results from the direct change of some ot tin ] 

 teid substance or whether it is a secretion. Ihc conditi 

 are somewhat different when pyrenoids are present in a cl 

 matophore as will be described presently. 



The chloroplasts of higher plants mav change color m 

 various conditions and become chromoi)lasts. Some of the 



