216 MiyUTK Ay ATOMY OF FLUW'Eltl.XG PLANTS 



vacuoles is the cell sap. It is sometimes colored. Tlie 

 red and yellow colors of health}' leaves are generally due 

 to colored cell sap in some of the cells, masking the 

 green of the cliloroph3dl granules. Bright colors of fruits 

 and flowers also are generally due partly to colored cell 

 sap. Tlie cell sap may contain sugar in storage, as it does 

 in the root of the sugar beet and in the stem of the sugar 

 cane. 



Certain suhstances belonging to the class oi formed mat- 

 ters (non-protoplasmic ) are of such frequent occuri-ence 

 and are produced in masses of such 

 size in the cell that they should be 

 brieflv described. 



499. Starch. ^Starch is the form 

 in \\diich elaborated plant food is most 

 <Minnnonly stored. It is laid down in 

 the Cells of storage organs, e.g. tubers, 

 in rounded granules (Fig. 363). A\'hen 

 these are considerably magnilied they 

 are seen to be stratified, in evidence of 

 the mode of dep(jsition of the starch in successive layers. 

 If the granules ay 



363. Starch culls Iroiu 

 Potato tuber. 



closely 2''"'kcd to- 

 gether, tliey m;i\ 

 Ijceome tiiignhtr io- 

 stead of rounded. 



500. Protein' gran- 

 ules and crystals. — 

 Ihe external stor- 

 age cells of wlieat 

 grtuns affoi'd exam- 

 ples of protein gran- 

 ules (Fig. 364 ). The 

 contents of these 

 cells make up the 

 so-called "luten of 



,^°9SOOQQOOO00C 

 ^^ -^O c^ r> <:; Cr-^ c^o? co c::::^ 



1» 



lij-l. Ti-aiisversc siTlimi near the outside nt a Wlicat 

 (jrain ; ("^ the liuslv (pericarp. iute;;ttnieiits) : 

 b, cells with protein granules; c, starch 



cells. — TSCHIKCH. 



^ Protein is tlie name ffiven to organic substance, whether of animal or 

 of vegetable origin, containing nitrogen and a small proportion o£ other 



