leukoplasts

Leucoplasts, also spelled leukoplasts, are colorless plastids found in plant cells. They are non-photosynthetic organelles that usually function in storage or biosynthetic processes, distinct from chloroplasts and chromoplasts. Leucoplasts arise from proplastids during cell differentiation and can differentiate into several specialized forms depending on tissue type and developmental cues. In non-photosynthetic tissues such as roots, tubers, seeds, and some fruits, leucoplasts are the dominant plastids.

The main forms of leucoplasts are amyloplasts, elaioplasts, and proteinoplasts. Amyloplasts store starch in the form of granules and are abundant in tissue like potato tubers and endosperm; they also play a role in gravity sensing in certain plant parts. Elaioplasts store lipids and oils and are common in seeds and oil-rich tissues. Proteinoplasts store protein bodies and are found in seeds and other storage organs. While each type is specialized for a particular nutrient, these plastids share the general features of lacking chlorophyll and containing plastid DNA, ribosomes, and a suite of imported proteins encoded by the plant nucleus.

Leucoplasts are dynamic and can transform in response to developmental signals or environmental conditions. In light-exposed tissues, they may convert into chloroplasts, enabling photosynthesis, whereas in darkness they may remain non-photosynthetic. These plastids also participate in broader metabolic pathways, including biosynthesis of fatty acids, starch, and storage proteins, contributing to the plant’s energy reserves and seed viability.