Department of Biology, University of Oregon, Eugene, USA.
Planta. 1972 Dec;106(4):311-24. doi: 10.1007/BF00384768.
Geotropic behavior in roots of Convolvulus arvensis is influenced by both gravity and light. In darkness, the roots grow horizontally; exposure to light induces a positive orthogeotropic response. The response is elicited by red light of narrow band width and is reversed by a far-red-light treatment following the red exposure. Phytochrome thus mediates this light response. Experiments with microbeam irradiation suggest that this pigment is located in the root apex, probably in the root cap. Statoliths are present and are shown to sediment upon reorientation of the root apex in both light-and dark-grown roots.
卷曲旋花的根的向地性受重力和光二者的影响。在黑暗中，根水平生长；而光的照射则会诱导出正向的向光性反应。这种反应是由窄频带的红光引发的，并可被红光照射后的远红光处理所逆转。因此，光敏色素介导了这种光反应。用微光束照射的实验表明，这种色素位于根尖，可能在根冠中。在光照和黑暗条件下生长的根中，当根尖重新定向时，均可见到平衡石沉降。
