Evening Republican, Volume 22, Number 279, Rensselaer, Jasper County, 19 November 1919 — Why the Tree Leaves Turn Red When Chilly Autumn Days Return [ARTICLE]

Why the Tree Leaves Turn Red When Chilly Autumn Days Return

An examination of the withered leaves of the autumn foliage at the time of their turning' red shows that they contain more sugar and less starch than in midsummer. "Leaves of -evergreens, however, lose their red tints with the return of the warm season, and reassume their green color. In these plants—i. e., the holly and ivy —the sugar of the leaf is transformed into starch in springtime. From these observations two inferences can be drawn—first, that the red coloring substances are probably of the nature of the glucoses, being in most cases compounds of tannic substances with sugar; second, the chief physical conditions for the formation of the red color are sunshine, which, on the one hand, enhances the assimilation and produclion of sugar, and, on the -other jhand, quickens the chemical process that leads to the formation of the coloring mattery and. furthermore, a low temperature, which prevents the transformation of the sugar into stafeif. Id other words, the red tints of autumn are the direct product of the meteor.ological conditions prevailing during that season—i. e., sunshine and low temperature. -