2005 Volume 49 Issue 2 Pages 132-139
Apparent photosynthetic rate of leaf (Pa), stomatal conductance to water vapor (Gs) and leaf N concentration (Lf-N) of pigeonpea grown in a Vertisol field were depressed by 3-day waterlogging. Pa, Gs and Lf-N were 35, 19 and 70%, respectively, of the control plants at 1 day after the end of the waterlogging treatment (DAW) . Lf-N and Pa recovered simultaneously during the subsequent period of waterlogging by the of implementation of N top-dressing (50 kg ha-1) at 1 DAW, while Gs did not recover sufficiently to the level of the control plants. Shortduration pigeonpea accumulated more starch in stems when the normal root activity was severely depressed by the waterlogging treatment. During the subsequent recovery period, the amount of starch accumulated in stems decreased gradually without N top-dressing, while more rapidly with N top-dressing. 14C export from the 14C-fed leaf of short-duration pigeonpea was significantly depressed immediately after 3-day waterlogging, but recovered quickly and a considerable amount of 14C was transferred to stems soon after the release from waterlogging.
In the present study we observed that short-term waterlogging reduced the Pa of short duration pigeonpea and the early Pa depression might be caused mainly by the decrease of Gs, while the continued depression of Pa after waterlogging would be limited by Lf-N. We also concluded that short-duration pigeonpea could store photoassimilates temporarily in stems and utilize them to survive under the unfavorable conditions such as waterlogging and that N top-dressing could promote the utilization for the recovery.
