Esau K, Cronshaw J, Hoefert L L
J Cell Biol. 1967 Jan;32(1):71-87. doi: 10.1083/jcb.32.1.71.
In minor veins of leaves of Beta vulgaris L. (sugar beet) yellows virus particles were found both in parenchyma cells and in mature sieve elements. In parenchyma cells the particles were usually confined to the cytoplasm, that is, they were absent from the vacuoles. In the sieve elements, which at maturity have no vacuoles, the particles were scattered throughout the cell. In dense aggregations the particles tended to assume an orderly arrangement in both parenchyma cells and sieve elements. Most of the sieve elements containing virus particles had mitochondria, plastids, endoplasmic reticulum, and plasma membrane normal for mature sieve elements. Some sieve elements, however, showed evidence of degeneration. Virus particles were present also in the pores of the sieve plates, the plasmodesmata connecting the sieve elements with parenchyma cells, and the plasmodesmata between parenchyma cells. The distribution of the virus particles in the phloem of Beta is compatible with the concept that plant viruses move through the phloem in the sieve tubes and that this movement is a passive transport by mass flow. The observations also indicate that the beet yellows virus moves from cell to cell and in the sieve tube in the form of complete particles, and that this movement may occur through sieve-plate pores in the sieve tube and through plasmodesmata elsewhere.
在甜菜（Beta vulgaris L.）叶片的小静脉中，在薄壁细胞和成熟筛管分子中均发现了黄化病毒颗粒。在薄壁细胞中，颗粒通常局限于细胞质中，即液泡中没有颗粒。在成熟时没有液泡的筛管分子中，颗粒散布在整个细胞中。在密集聚集中，颗粒在薄壁细胞和筛管分子中都倾向于呈有序排列。大多数含有病毒颗粒的筛管分子具有成熟筛管分子正常的线粒体、质体、内质网和质膜。然而，一些筛管分子显示出退化的迹象。病毒颗粒也存在于筛板的孔中、连接筛管分子与薄壁细胞的胞间连丝以及薄壁细胞之间的胞间连丝中。甜菜韧皮部中病毒颗粒的分布与植物病毒通过筛管在韧皮部中移动且这种移动是通过质量流进行的被动运输这一概念相符。这些观察结果还表明，甜菜黄化病毒以完整颗粒的形式在细胞间和筛管中移动，并且这种移动可能通过筛管中的筛板孔以及其他部位的胞间连丝发生。
