Response to salinity in Glycine. 5. Changes in the chemical composition of three Australian species of G. wightii (G. javanica) over a range of salinity stresses

Abstract

Changes in chemical composition due to salinity were compared for native Australian and introduced Glycines at the end of a ten day salt treatment which was imposed on young seedlings when they had five trifoliate leaves, and at later harvests during a period of recovery. The species compared were G. falcata, G. tomentella, G. tabacina, and the introduced G. wightii (formerly G. javanica)--m. Cooper and Tinaroo. The range of salinities was 0 to 160 m-equiv. sodium chloride/litre of nutrient solution. Salinity adversely affected nutrient composition both as regards uptake and distribution of potassium and nitrogen and for the ratio of potassium/sodium in the plant parts. This persisted during the 14-day recovery phase when rates of uptake were depressed for the high salt plants. None of the Glycines fully regained control levels of growth and nutrient composition after the removal of salt, although the difference in their ability to recover paralleled limitation due to salinity stress. The extremes in response were G. wightii (G. javanica) CV. Cooper, cv. Tinaroo, and G. falcata least affected, and G. tomentella most affected. G. tabacina was intermediate in response. G. falcata was the most interesting of the Australian species, being comparable with G. wightii (javanica) CV. Cooper except for lower nitrogen content due to salinity. All three Australian species had higher phosphorus concentrations at the control level than the G. wightii (javanica) cultivars so that the ability of G. falcata to maintain this despite salinity stress is a valuable agronomic feature of this species.