Abstract
In epidermal cells of Vallisneria gigantea, hight-intensity blue light (BL) induces the avoidance response of chloroplasts. BL remarkably decreases the resistance of chloroplasts to centrifugal force. This BL-induced dis-anchorage of chloroplasts occurs before the start of directional movement of chloroplasts.
In several plants, BL induces a Ca2+ transient. On the other hand, chloroplasts take up or release Ca2+, responding to changes in light conditions.
To ascertain a possibility that Ca2+ is involved in the induction of avoidance response of chloroplasts, we examined the effects of Ca2+-channel blocker (La3+), phospholipase C inhibitor (U73122), and photosynthesis inhibitor (DCMU). These drugs suppressed the avoidance response additively, and when all three drugs were present, the response was completely inhibited. The BL-induced dis-anchorage of chloroplasts was substantially suppressed in the presence of La3+ and U73122. These results suggest that Ca2+ from different stores is involved in the induction of avoidance response of chloroplasts.
