In a laboratory setting, boiling chloroplasts essentially prevents the reduction of 2.6-dichlorophenol-indophenol (DPIP). This artificial electron acceptor is used in place of nicotinamide adenine dinucleotide phosphate (NADP+) to measure photosynthetic activity.
Chloroplasts are specialized structures in plants that serve as the site for photosynthesis. The application of heat beyond the optimal level results in the denaturation of the enzymes present within these units, which leads to a decline in photosynthetic activity.
In an experimental setup, little to no reduction of DPIP indicates that the NADP+ in boiled chloroplasts will not be converted to NADPH, which is the reduced form of NADP+. Along with adenosine triphosphate (ATP), NADPH is vital during the dark reaction stage of photosynthesis. Without these two components, the production of glucose is not possible.