WONDIMAGEGNE SHIFERAW, H.M. SHELTON and H.B. SO
Department of Agriculture, University of Queensland, Brisbane, Australia
The waterlogging tolerance of 8 pasture legumes was studied in a glasshouse at the University of Queensland, Brisbane, Australia during the spring of 1989. The species were Lotus pendunculatus cv. Maku and accessions G4704 and 67677, L. corniculatus accession G32, Vigna parkeri cv. Shaw, Trifolium semipilosum cv. Safari, Aeschynomene americana cv. Glenn and Medicago sativa cv. Trifecta. Waterlogging treatments were inundation to 3 cm above soil level for 0, 3, 7 or 14 days.
The redox potential of the yellow podzolic soil (typic haploxerult) dropped from + 350 millivolts (mv) to – 300 mv after 14 days waterlogging, indicating that anaerobic conditions prevailed. The species most tolerant of waterlogging were A. americana followed by L. pendunculatus cv. Maku and T. semipilosum. These species transpired the highest amounts of water immediately after waterlogging was imposed, accumulated the highest concentrations of manganese in plant tops, and produced adventitious roots. Tolerance in L. pendunculatus cv. Maku was also indicated by thickening of submerged stems and suberisation of roots. The remaining Lotus species showed medium tolerance. The most susceptible species were M. sativa and V. parkeri which showed the lowest rates of transpiration, lowest concentrations of manganese in shoots, greatest reduction in plant weight due to waterlogging, and finally wilting and death.
All species showed reduced nodulation and nitrogen concentrations in shoots following waterlogging.