Abstract:
Soil salinity suppresses plant growth by reducing, among other factors, the acquisition of essential nutrients by roots and their transport to shoots. However, studies on the intra-specific differences in nutrient accumulation under salinity are scarce. A study was conducted to determine varietal differences in (a) nodal mineral concentrations and (b) sprouting, growth, and nutrient acquisition by sprouts of 7 sugarcane varieties under increased NaCl salinity. Although significant varietal differences were observed in sprouting, shoot and root dry mass, and number of roots in saline soil, varieties CPF-237 and CP-4333 had a smaller reduction in most of these attributes. Although non-significant, varieties exhibited differences in the nodal nutrient contents, which were correlated with sprouts' growth characteristics and appeared to have great involvement in the salinity tolerance of the varieties. All the varieties accumulated Na+ and Cl- in saline soil, and all had a reduction in macro- and micronutrients. No correlations were shown between Na+ or Cl- and the level of the nutrients under control. However, correlations of Na+ and Cl-, although negative with dry weights, were more significant for shoots than for roots under salinity stress. Among the nutrients, the shoot and root dry weights were more highly correlated with the micronutrient than with the macronutrient contents, suggesting a possible involvement of the former in salinity tolerance of sugarcane. In conclusion, sugarcane varieties showed fewer differences in the endogenous nodal bud nutrients but varied greatly in the acquired micronutrient concentrations by the sprouts. Thus the management of saline fields with appropriate micronutrient supply may have great implications for accruing better sugarcane yield from saline fields.