Response to salinity in Glycine. 4. Salt concentration and the content of phosphorus, potassium, sodium and chloride in cultivars of G. wightii (G. javanica)

Adaptability to salinity stress was related to the productivity of Glycine wightii (G. javanica) cultivars by the technique of comparing the multivariate characteristics of response for 22 accessions that are representative of the world centres of origin. Roots and tops responses were compared to clarify the metabolic relations between glycines, as salinity was increased from that required for normal growth and metabolism to levels almost causing death due to excess sodium chloride in the substrate. There was a range and pattern of response that suggested grouping among the glycines. One group in particular was more resistant to salinity stress than others. These glycines exemplified to a greater degree than others the tendency of all to exclude sodium and to a lesser extent chloride from the plant tops. These were also the more vigorously growing glycines with a higher potassium, phosphorus, and nitrogen content in both control and saline treatments. In them, vigour of growth and control of ion content were associated, and both these factors were important determinants of tolerance to salinity stress. Sodium appeared to be more toxic than chloride to plant growth. These aspects of growth and metabolism are discussed in relation to differences in ploidy between the groups of glycines. The technique used shed further light on the important agricultural problem of combining adaptability and high productivity.