Roberts I N, Harrod G, Dickinson H G
J Cell Sci. 1984 Mar;66:241-53. doi: 10.1242/jcs.66.1.241.
The osmotic potential (psi pi) of the stigmatic papillar cells of Brassica oleracea is -14.8 bars. In laboratory conditions each cell transpires water at rates within the range from 3 X 10(-5) to 5 X 10(-5) mm3h-1. A small increase in transpiration rate is detected following cross-(compatible) but not self-(incompatible)pollination. No significant changes in psi pi occur following pollinations of either compatibility. Electron microscopy reveals an active papillar cytoplasm apparently secreting proteins into the cell wall via small vesicles. The cuticle is discontinuous and freeze-fracture techniques indicate that channels transverse the cell wall, suggesting a possible pathway for the movement of protein molecules of high molecular weight from the cytoplasm to the stigma surface. Analysis of electron-microscopic autoradiographs of mature, self-incompatible papillae following pulse-chase experiments with L-[3H]leucine and treatment with cycloheximide shows that protein molecules secreted into the cell wall may return to the cytoplasm at a later stage. The significance of these results is discussed in terms of current models of the pollen-stigma interaction in Brassica.
甘蓝型油菜柱头乳头状细胞的渗透势（ψπ）为-14.8巴。在实验室条件下，每个细胞的水分蒸腾速率在3×10⁻⁵至5×10⁻⁵立方毫米/小时范围内。在异花（亲和）授粉后可检测到蒸腾速率略有增加，但自花（不亲和）授粉后则无此现象。无论授粉亲和与否，ψπ均无显著变化。电子显微镜观察显示，活跃的乳头状细胞质明显通过小泡将蛋白质分泌到细胞壁中。角质层不连续，冷冻蚀刻技术表明有通道横穿细胞壁，这表明高分子量蛋白质分子从细胞质转移到柱头表面可能存在一条途径。在用L-[³H]亮氨酸进行脉冲追踪实验并经环己酰亚胺处理后，对成熟的自交不亲和乳头进行电子显微镜放射自显影片分析表明，分泌到细胞壁中的蛋白质分子可能在后期返回细胞质。本文根据甘蓝型油菜花粉与柱头相互作用的当前模型对这些结果的意义进行了讨论。
