Transport Physiology Research Group, Botanisch Laboratorium, Universiteit Utrecht, Lange Nieuwstraat 106, 3512 PN Utrecht, the Netherlands.
Plant Physiol. 1988 Nov;88(3):667-70. doi: 10.1104/pp.88.3.667.
We have stripped small (3 x 3 mm) fields of the upper and the opposite lower epidermis of Commelina benghalensis leaves. Pectinase treatment of the resulting chlorenchyma windows produced free-lying viable minor veins with small lumps of mesophyll cells attached. These veins were still connected with the intact remainder of the leaf. Fluorescent dyes were injected into mesophyll cells or mestome sheath cells. Continuous following of the dye from the moment of injection and use of the simple vein system allowed an unhindered and precise assessment of the cell-to-cell route of dye transfer. Disodium fluorescein and Lucifer Yellow CH injected into mesophyll or mestome sheath cells readily moved to the sieve tube. This symplastic dye transfer from mesophyll to sieve tube was also observed after injection into unmacerated stripped leaf tissue. The displacement of fluorescent dyes substantiates a symplastic continuity between mesophyll and sieve tube and therefore supports the possibility of symplastic phloem loading.
我们已经剥离了孟加拉鸭跖草叶片的上表皮和对侧下表皮的小（3x3 毫米）区域。果胶酶处理由此产生的叶绿体窗产生了自由附着的有活力的小脉，附有小块的叶肉细胞。这些脉与完整的叶片其余部分仍然相连。荧光染料被注入叶肉细胞或中柱鞘细胞。从注射的那一刻起，对染料进行连续跟踪，并使用简单的叶脉系统，使得染料转移的细胞间途径能够不受阻碍地、精确地进行评估。注射到叶肉或中柱鞘细胞中的二钠盐荧光素和 Lucifer Yellow CH 很容易转移到筛管。这种从叶肉到筛管的胞质染料转移在未浸渍剥离的叶片组织中也有观察到。荧光染料的位移证实了叶肉和筛管之间存在胞质连续性，因此支持了胞质韧皮部装载的可能性。
