Heathcote D G, Bircher B W
Department of Plant Science, University College, Cardiff, UK.
Planta. 1987;170:249-56.
The phototropic dose-response relationship has been determined for Triticum aestivum cv. Broom coleoptiles growing on a purpose-built clinostat apparatus providing gravity compensation by rotation about a horizontal axis at 2 rev min-1. These data are compared with data sets obtained with the clinostat axis vertical and stationary, as a 1 g control, and rotating vertically to examine clinostat effects other than gravity compensation. Triticum at 1 g follows the well-established pattern of other cereal coleoptiles with a first positive curvature at low doses, followed by an indifferent response region, and a second positive response at progressively increasing doses. However, these response regions lie at higher dose levels than reported for Avena. There is no significant difference between the responses observed with the clinostat axis vertical in the rotating and stationary modes, but gravity compensation by horizontal rotation increases the magnitude of first and second positive curvatures some threefold at 100 min after stimulation. The indifferent response is replaced by a significant curvature towards the light source, but remains apparent as a reduced curvature response at these dose levels.
已确定了在专门制造的回转器装置上生长的普通小麦品种Broom胚芽鞘的向光剂量-反应关系，该回转器通过绕水平轴以每分钟2转的速度旋转来提供重力补偿。将这些数据与在回转器轴垂直且静止（作为1g对照）以及垂直旋转以检查除重力补偿之外的回转器效应时获得的数据集进行比较。在1g条件下的普通小麦遵循其他谷物胚芽鞘已确立的模式，即在低剂量时首先出现正向弯曲，随后是无反应区域，在剂量逐渐增加时出现第二次正向反应。然而，这些反应区域所处的剂量水平高于燕麦的报道。在旋转和静止模式下，回转器轴垂直时观察到的反应之间没有显著差异，但在刺激后100分钟，通过水平旋转进行重力补偿会使第一次和第二次正向弯曲的幅度增加约三倍。无反应区域被朝向光源的明显弯曲所取代，但在这些剂量水平下，作为降低的弯曲反应仍然明显。
