Fig. 3

Ultrastructure of the sieve element-companion cell complex (SE/CC) and its surrounding parenchyma cells (PCs) in developing tomato fruit. All sections were cut transversely. Left, hexose-accumulating cherry tomato. Right, sucrose-accumulating cherry tomato. The structures of the phloem of the two kinds of cherry tomato are shown in the upper left picture. The SEs, CCs and PCs are labeled. I-V, ultrastructure between SE/CCs and PCs during developmental stages I to V. plasmodesmata are labeled by red arrows. Abbreviations: SE, sieve element; CC, companion cell; PC, phloem parenchyma cell; PD, plasmodesmata; M, mitochondrion; Ve, vacuole; H, hexose-accumulating cherry tomato; S, sucrose-accumulating cherry tomato. I, immature stage; II, mature green stage; III, breaker stage; IV, pink stage; V, red ripe stage