Haindl E, Monzer J
Lehrstuhl fur Botanik, Technische Universitat Munchen at Weihenstephan, Freising, Germany.
Exp Mycol. 1994 Jun;18(2):150-8. doi: 10.1006/emyc.1994.1016.
Differential elongation of stipe hyphae drives the gravitropic reorientation of Flammulina velutipes (Agaricales) fruiting bodies. The gravitropic curvature is strictly dependent on the presence of the transition zone between pileus and stipe. Elongation growth, providing the driving force for curvature, is also promoted by the pileus. Gravitropic curvature is successfully suppressed by clinostatic rotation, but the elongation rate is not affected. Explantation of fruiting body stipes lowers curvature and elongation rates corresponding to explant size reduction. In Flammulina, 25 mm length of transition zone explants is an efficient size for reproducible curvature and elongation during 48- to 72-h curvature tests. Submersion of specimens in aqueous medium causes cessation of the gravitropic curvature, but does not affect elongation. Thus the involvement of a diffusible factor in transmission of the curvature signal is probable. Splitting the fruiting body stipe in segments of 1/8 diameter does not suppress the gravitropic response, and the segments are individually reoriented to the vertical. It is concluded that the graviresponse of the Flammulina fruiting body is based on cellular perception of the gravistimulus and that a differential growth signal is transmitted in the stipe by a soluble factor that regulates hyphal elongation.
菌柄菌丝的差异伸长驱动金针菇（伞菌目）子实体的向重力性重新定向。向重力性弯曲严格依赖于菌盖和菌柄之间过渡区的存在。提供弯曲驱动力的伸长生长也受到菌盖的促进。向重力性弯曲通过水平回转成功抑制，但伸长率不受影响。子实体菌柄的外植体降低了与外植体尺寸减小相对应的弯曲度和伸长率。在金针菇中，25毫米长的过渡区外植体是在48至72小时弯曲试验期间实现可重复弯曲和伸长的有效尺寸。将标本浸入水性介质中会导致向重力性弯曲停止，但不影响伸长。因此，很可能有一个可扩散因子参与弯曲信号的传递。将子实体菌柄切成1/8直径的片段不会抑制向重力性反应，并且这些片段会各自重新定向到垂直方向。得出的结论是，金针菇子实体的重力反应基于细胞对重力刺激的感知，并且差异生长信号通过调节菌丝伸长的可溶性因子在菌柄中传递。
