Destarching occurs in a plant when a part of a plant is "deprived of starch, as by translocation". It is also the process of eliminating

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...

reserves in a plant for experiments concerning

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

. This is done by leaving the plant(s) in a dark place for 3 days. Due to the lack of photosynthesis in this place, stored starch is used up, thus the plant is destarched.

References

Plant physiology {{Botany-stub