Abstract
Root hair elongation induced by acidic stress requires high fluence blue light (3.6 Wm-2, more than 9hr). This fact suggests the possibility that photosynthesis or its products are essential for induction of root hair elongation.
One day old roots grown under blue light for 9hr slightly contained chlorophylls (1.8 μg/ Fw g), while roots grown under red light did not. One hundred μM DCMU and 10 μM DBMIB inhibited the elongation completely. However, this inhibition was not recovered by addition of sugars. Pulse amplitude modulation fluorometer (Walz, PAM101/102/103) could not detect photosynthesis activity in roots grown under red or blue light. Furthermore, sugars could not induce root hair elongation in the darkness although main root elongation was enhanced (Suc; 3 times, Glc; 1.5 times).
Considering these results and that red light cannot induce root hair elongation, photosynthesis does not promote root hair elongation.
