Botany Department, Queen's University, Belfast, N. Ireland.
Planta. 1967 Mar;78(1):60-71. doi: 10.1007/BF00384858.
Radioactive amino acids are fed singly to intact shoots of field pea (Pisum arvense L.) via the transpiration stream. The range of radiosubstrates used is chosen to be representative of those compounds exported in quantity from the root system of field pea. The distribution of radioactivity from each substrate suggests that mature organs actively assimilate materials which enter the shoot through the xylem. During a four hour period 5-20% of the label recovered from mature tissues is present in insoluble form, much of this as protein.A microautoradiographic technique is used to localize insoluble labelled materials in thin (1-2 μ) sections of the plant tissues. Certain cell types (xylem parenchyma, cambial initials, mesophyll of leaves, chlorenchyma of stem and petiole, and all elements of the phloem) appear to be particularly active in elaborating protein and other structural constituents from the labelled substrates. Preferential labelling of chloroplasts is observed in cells of mesophyll, while in all cells the wall components appear to be less readily labelled than their contained protoplasts.
放射性氨基酸通过蒸腾流被单独输送到野外豌豆（Pisum arvense L.）的完整芽中。所用放射性底物的范围选择为从野外豌豆根系中大量输出的那些化合物的代表。每个底物的放射性分布表明，成熟器官主动同化通过木质部进入芽的物质。在四个小时的时间内，从成熟组织中回收的标记的 5-20%以不溶性形式存在，其中大部分为蛋白质。一种微量放射自显影技术用于在植物组织的薄（1-2 μ）切片中定位不溶性标记的物质。某些细胞类型（木质部薄壁组织、形成层原始细胞、叶片的叶肉、茎和叶柄的叶绿体以及韧皮部的所有元素）似乎特别活跃，从标记的底物中精心制作蛋白质和其他结构成分。在叶肉细胞中观察到叶绿体的优先标记，而在所有细胞中，细胞壁成分似乎比其包含的原生质体更不易标记。
