Photosynthesis - light factor - basic principle

Procedure to test light as a factor Note the color change in specific areas of the leaf Bleached leaf is placed in a petri dish and Lugol's is added to the dish Hot alcohol breaks down cell emmbranes, pigments leach out of the cells, and the leaf is bleached After removal of the cardboard, the leaf was boiled in hot alcohol Geranium plant was placed in a dark cabinet overnight; a leaf was covered with a cardboard and placed in light

End result Negative with Lugol's - absence of starch Positive with Lugol's - presence of starch Area of the leaf that did not receive light Area of the leaf that received light