. Biology; the story of living things. boilecL â âr^ in -^oodi â \>^ alcoViol positive reaction "where was locctte<:C. ergy, respires, feeds, repro- duces, and in time dies. But we must remember that in addition, the green plant makes food, and it is this process upon which we will now focus our attention. It is a relatively simple matter to prove that sun- light is necessary for starch making in a leaf. Place a healthy green plant in dark- ness for a couple of clays. Then pin strips of black cloth over parts of some of the leaves and expose the plant to bright sunlight fo
. Biology; the story of living things. boilecL â âr^ in -^oodi â \>^ alcoViol positive reaction "where was locctte<:C. ergy, respires, feeds, repro- duces, and in time dies. But we must remember that in addition, the green plant makes food, and it is this process upon which we will now focus our attention. It is a relatively simple matter to prove that sun- light is necessary for starch making in a leaf. Place a healthy green plant in dark- ness for a couple of clays. Then pin strips of black cloth over parts of some of the leaves and expose the plant to bright sunlight for a few hours. Later, remove the leaves and boil them to soften the tissues, adding alcohol to extract the chlorophyll, and finally, place them in a solution of iodine. A blue color will appear in those parts of the leaves exposed to sunlight, while the covered areas will be colorless. The appearance of the blue color in the presence of iodine is the regular test for starch, thus showing clearly that sunlight is necessary for starch making. Another simple experiment may be performed to show that air is also a necessary factor. Place a healthy green plant in darkness for two or three days, then carefully smear vaselin(> on th(> ui)i)(>r and lower surface of two or three l(?aves, leaving the others uiitoiiclicd. Proof that light is necessary for starch forma- tion in green Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hunter, George W. (George William), 1873-1948; Walter, Herbert Eugene, b. 1867; Hunter, George W. (George William), 1902-. New York, Cincinnati [etc. ] American book company
Size: 1825px × 1369px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorwalterherberteugeneb1867, bookcentury1900, bookpublish
