FIGURE 1.

Transmission electron microscopy of a maize seed at mid-developmental stage (14 dap, Stage 2). (A) Composed image comprising aleurone, sub-aleurone, and starchy endosperm. The nucleus (n) and the prominent electron transparent vacuole-like structures (arrows), as well as small, scarce starch grains (s) are indicated in the sub-aleurone cells. Large and abundant starch granules (s) are found in the starchy endosperm. (B) Enlargement from inset in [(A), framed box], showing starchy endosperm cells with prominent ER strands (double arrows), abundant protein bodies (arrowheads) and starch grains (s). Cell walls (cw), mitochondria (m). Scale bars, 2 μm.