| A comparative study on photosynthetic characteristics between the genetic modified sweet potato transferred
with the Cu/Zn SOD and APX genes (TS) and non-GM sweet potato (NS) was carried out with pot experiments. Three
controls, namely the favorable soil moisture (75%~80% of field water capacity, FWC), the moderate drought (60%~65% of
FWC) and the severe drought (35%~40% of FWC) groups were used. The Result showed that light response curves of the
TS and NS had no significant difference under these three soil moisture conditions. The fitting result showed good
performance by non-rectangular hyperbolic model. The net photosynthetic rate (Pmax), light saturation point (LSP) and
apparent quantum efficiency , dark respiration rate (Rd) of both TS and NS plants decreased significantly under drought
conditions and then continually increased. However, the decrease of TS plant was less than NS plant under stress condition
and the recovering was quicker. These results indicated that overexpressing antioxidant enzyme genes enhanced sweet
potato photosynthetic capacity, adaptability of drought stress and recovery capability. Light compensation point (LCP) of
sweet potato increased significantly under drought stress, but the rise in TS plants was less than NS control. These results
showed that transgenic genes to sweet potato enhanced its light environmental adaptability |
