Chlorophyll

klo'ro-fil, the green coloring matter of plants. The term is Greek and means leaf green. Chlorophyll is a granular pigment contained in the living cells, especially the young cells, of plants. Sunlight is required to bring out its color. Plants kept in darkness for a time become white and waxy. The grains of coloring matter accumulate usually in the upper cells of a leaf, giving that surface a greener color than the under parts. The reds and other brilliant colors of autumn foliage are due to the combination of various minerals with the green pigment of chlorophyll. Hardened tissues and autumn frosts facilitate the operation. Chlorophyll is an important agent in the digestion of plant foods, a process which takes place in the leaves.