Effects of waterlogging on seed germination, electric conductivity of seedleakage and developments of hypocotyl and radicle in sudangrass

Sudangrass (Sorghum sudanense Stapf) is a short-period forage species adapt ed to growth in Taiwan. The objectives of the experiment were to determine the effects of waterlogging on seed germination, electric conductivity of s eed leakage and developments of hypocotyl and sudangrass and provide inform ation for selecting the lines with tolerance to waterlogged stress. Sudangr ass, CV. Taishi No. 1, was used for the experiment. In the germination test , the seeds were waterlogged for 3 days at 0, 1, 2 and 3 days after imbibin g. The seeds waterlogged at 0 day after imbibing had the lowest germination percentage. The potassium contents of the seed leakages were increased and contents of both total sugar and reducing sugar in the seed leakages were decreased with an increase in imbibing period. The relationship between ger mination percentage and electric conductivity was negatively correlated (p< 0.05), indicating that the electric conductivity could be used to evaluate the germination ability of sudangrass. For the emergence test, the sudangra ss seeds were waterlogged for 0, 1, 2, 3, 4, 5, 6 and 7 days after sowing. The emergence percentages of sudangrass were not significantly different am ong treatments, while the emergence rate indices and the corrected emergenc e rate indices decreased with the increase in waterlogging period. This ind icated that the emergence ability of sudangrass was reduced by waterlogging after sowing. The hypocotyl or the radicle cortex of sudangrass with a low germination or emergence percentage was damaged during waterlogging. The r esults demonstrated that: (1) the germination percentage of sudangrass was seriously affected when seeds were waterlogged before imbibing, (2) the ele ctric conductivity of the seed leakage could be used to evaluate the germin ation ability of sudangrass.