Regulation About Expression Of Amylase In Calli Of Sweet Potato

The stem explants of sweet potato were used to induce calli. After cultured in media supplemented with different concentration of abscisic acid (ABA), gibberellin(GA3) and sugars for 15 days , the calli were compared with their morphological characters and measured amylase' activity . The alteration of amylase' activity was surveyed after calli were treated with NaCl.The growth and aspect of calli could been changed with different concentration ABA, GA₃, sucrose, and illumination. The calli grew fast, whitish and loosen with 3% sucrose. Exposed to ABA, the calli grew faster and whiter. Exposed to GA3, the calli grew faster and whiter at 0.5mg/L, but had no remarkable change at 1.5 mg/L or 3.0 mg/L. Treated with illumination, the color of calli changed to a little green. The calli growed slowly and were looked as yellow, compact, waterish without 2,4-D and 6-BA. At this time, calli exposed to ABA grew faster than exposed to GA3.As a result, the activity of amylases were lower according to low concentration of sucrose. On a calli fresh weight basis, 3% treatments resulted in a top activity of amylases, but 6% treatments showed lower activity of amylase, and 9% showed almost zero activity. ABA always showed the advance to amylase in low or high concentration of sucrose. And this advance still existed inillumination treatment. The regulation of GA3 to activity of amylases was different in different concentration of sucrose or illumination treatment. Such before-mentioned result was not changed if the substrate without 2,4-D and 6-BA.The activity of amylases showed a vale after addition of NaCl, and this vale was retained for 12-36 hours for different concentration of NaCl. Then the activity resumed. There were two peaks in most treatments, which the first one appeared at 36-48 hours, and another appeared at 60-84 hours.