noun, plural: amyloplasts
(botany) A type of leucoplast found in the cytoplasm of a plant cell, and serves as storage organelle of amylopectin
Plastids are organelles involved in the synthesis and storage of food. They are found within the cells of photosynthetic eukaryotes. In plants, plastids may develop into these forms: (1) chloroplasts, (2) chromoplasts, (3) gerontoplasts, and (4) leucoplasts. Leucoplasts are colourless plastids because they lack pigments. Their role is primarily for storage. Depending on the content of the leucoplasts, they may be amyloplasts, elaioplasts, proteinoplasts, or tannosomes.
Amyloplast is a leucoplast that is primarily involved in storing starch and detecting gravity. As for storing starch, the amyloplasts transform glucose into starch by polymerization of glucose and store the starch grains in the stroma. Most of the amyloplasts can be found in underground storage tissues of plants, such as potato. The amyloplasts, though, can turn into chloroplasts, such as seen in potato tubers that are exposed to light. They become green as the amyloplasts convert into chloroplasts.
As for detecting gravity, the amyloplasts are able to perceive gravity (gravitropism). These amyloplasts involved in gravitropism are referred to as statoliths.
Word origin: Gk ámylon (starch) + Gk plastós (formed, molded)