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

Abstract

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.

Comparative Efficiency of Development Under Cold Stress of the Tropical Legumes Lotononis Bainesii Baker and Stylosanthes Humilis H.B.K

“…The selected age and level of phosphorus nutrition were found favourable in previous studies for the growth of L. hainesii (Gates et al 1973) and for S. humilis (Gates et al 1966).…”

“…Previous studies in this laboratory (Gates et al , 1973 have suggested strongly that, in interspecific studies of response to stress, little interest resides in any individual variate. Although small differences between species for individual variates can be detected, the overall comparison is more meaningful when considered as an integrated set of such small differences.…”

“…Such regions are a feature of the northern half of Australia. The development of Lotononis bainesii Baker in response to specific amounts of cold stress has been described relative to its phosphorus nutrition and the age at which stress was imposed (Gates et al 1973). In that study of the interaction of nutrition, cold, and age, it was concluded that the response to chilling was multiple rather than discrete; for the normal pattern of growth response adapted constantly through time to treatment interaction.…”

“…The amount of cold stress imposed based on the departure from 25°C totalled: harvests 1 and 2, nil; harvest 3, 320 deg-hr; harvest 4, 1190 deg-hr; harvest 5, 2580 deg-hr; harvest 6, 4990 deg-hr departure from a constant 25°C (approximating to a quadratic curve of increase). Root temperature regimes are presented in Figure 2 where "normal" is the regime of the previous trial (Gates et al 1973), and "chilled" is lower than it by some 10°C, with the aim of impairing the development of the two species differentially. These root temperature regimes may be compared with typical curves (Fig.…”

“…Plants were thinned to four per pot. Time at which temperature regime imposed As in the previous trial (Gates et al 1973) the pots were shielded against changes in air temperature by insertion through an insulating lid of foam plastic into a large tank of water, under thermostatic control. It was thus possible to maintain a temperature difference between tops and roots.…”