Leucoplasts ("formed, molded") are a category ofplastid and as such areorganelles found inplant cells. They are non-pigmented, in contrast to other plastids such as the chloroplast.
Lackingphotosynthetic pigments, leucoplasts are located in non-photosynthetic tissues of plants, such asroots,bulbs andseeds. They may be specialized for bulk storage ofstarch,lipid orprotein and are then known asamyloplasts,elaioplasts, orproteinoplasts (also called aleuroplasts) respectively. However, in many cell types, leucoplasts do not have a major storage function and are present to provide a wide range of essential biosynthetic functions, including the synthesis of fatty acids such aspalmitic acid, many amino acids, and tetrapyrrole compounds such asheme. In general, leucoplasts are much smaller thanchloroplasts and have a variable morphology, often described as amoeboid. Extensive networks ofstromules interconnecting leucoplasts have been observed in epidermal cells ofroots,hypocotyls, andpetals, and incallus and suspension culture cells of tobacco. In some cell types at certain stages of development, leucoplasts are clustered around thenucleus with stromules extending to the cell periphery, as observed for proplastids in the root meristem.
Pre-granal etioplasts, which arechloroplasts that have not matured but can be chloroplasts deprived of light, lack the active pigment. They can thereby can be considered leucoplasts. After several minutes exposure to light, etioplasts transform into functioning chloroplasts and cease being leucoplasts. Amyloplasts are of large size and store starch.
Proteinoplasts store proteins and are found in seeds (pulses), while elaioplasts store fats and oils and are found in seeds. They are also called oleosomes.
