leucoplast

Leucoplasts are colorless plastids found in plant cells, distinguished from chloroplasts by the absence of photosynthetic pigments. They are common in non-photosynthetic tissues such as roots, tubers, seeds, and embryo cells, where they primarily store or synthesize compounds needed by the plant.

Leucoplasts include several subtypes based on their storage function. Amyloplasts store starch and contain starch grains; they are abundant in potato tubers and in root cap cells. Elaioplasts store lipids as oil bodies and are involved in lipid biosynthesis and accumulation. Proteinoplasts store proteins and may contain protein bodies. These subtypes can be collectively referred to as leucoplasts when discussing colorless plastids that are not primarily photosynthetic.

In addition to storage, leucoplasts participate in various biosynthetic pathways, including the synthesis of starch, lipids, and proteins, and they contribute to metabolic processes within non-photosynthetic tissues. They originate from proplastids in meristematic cells and can differentiate into other plastid types as tissues develop; conversely, plastids can transition between forms in response to developmental cues and environmental conditions.

Leucoplasts play a role in plant physiology beyond storage, including involvement in gravitropism in roots, where amyloplasts act as statoliths to help the plant sense gravity. Understanding leucoplast function helps explain how plants manage energy reserves and adapt to varying light and growth conditions.