Distribution of K, Na and Cl in Root and Leaf Cells of Soybean and Cucumber Plants Grown under Salinity Conditions

Abstract

The element contents in the compartments of root and leaf cells of soybean and cucumber plants grown for 8 d in a nutrient solution containing 50 mM NaCl, 25 mM CaCl2 or 50 mM NaCl+4.75 mM CaSO4 were examined by X‐ray microanalysis of freeze‐substituted dry sections. Sodium accumulated in the vacuoles rather than in the cytoplasm and apoplastic space in the root cells of the soybean plants, leading to the difficulty in the transport of Na to leaves in soybean. Salt injury of soybean is considered to be caused by the accumulation of Cl at high concentrations in all the compartments of root and leaf cells. In contrast, the accumulation of Na in the cytoplasm of the root and leaf cells might disturb the metabolism and lead to the occurrence of salt toxicity in cucumber plants, which are tolerant to Cl due to the stimulation of Cl accumulation in vacuoles when the Ca concentration was high in nutrient media.

Salinity Tolerance of Super-Nodulating Soybean Genotype En-b0-1

“…Therefore, the salinity tolerance in these soybean cultivars was associated with tolerance to both Na and Cl, although several previous studies had suggested that salt-induced inhibition of growth was more closely associated with Cl than Na contents in aboveground plant parts (Abel and Mackenzie, 1964;Abel, 1969;Parker et al,1983;Yang and Blanchar, 1993;Valencia et al, 2008;Ren et al, 2012). In this respect, Dabuxilatu and Ikeda (2005) ascribed the greater toxicity of Cl to its allocation within the plant: Cl was stored in both vacuoles and apoplastic spaces in both leaves and roots, whereas Na was predominantly stored in vacuoles in roots. In the present study, the saline conditions stimulated the accumulation of Cl more substantially than Na, particularly in shoots (Fig.…”

Genotype-Dependent Differential Responses of Three Forage Species to Calcium Supplement in Saline Conditions

“…Supplemental Ca is known to mitigate the adverse effects of salinity on plant growth (Dabuxilatu and Ikeda, 2005). Improvement of plant performance under saline condition using calcium supplement appears greatly to be depend on genetic ability of plant species.…”

“…On the other hand, inhibition of Na entry into roots via regulation of non-selective cation channels (Zhu, 2003) may decline sodium delivery to the plant tissues. Although, supplemental Ca, at least for some plants and conditions, may be a proper approach to moderate the deleterious impacts of salinity (Kent and Läuchli, 1985;Dabuxilatu and Ikeda, 2005). Calciumindependent component of the Na inhibition would negatively influence plant growth responses (Reid and Smith, 2000).…”

“…Negative interaction between sodium (Na) and calcium ions resulted in both inhibition of calcium uptake (Davenport et al, 1997) and translocation (Lynch and Läuchli, 1985). Supplemental Ca can increase potassium and make a decline in sodium content of plant tissues (Dabuxilatu and Ikeda, 2005). Calcium, through a decrease in Na activity at the cellular membrane surface, restores selectivity to the potassium (K) channels (Reid and Smith, 2000).…”

Regulation of plasma membrane aquaporins by inoculation with a Bacillus megaterium strain in maize (Zea mays L.) plants under unstressed and salt-stressed conditions

“…Benes et al (1996a, b) found that Cl ¡ leaf concentration of 80 mM caused growth inhibition in maize plants at harvest time. Therefore, Cl ¡ leaf concentration should not be the main cause of leaf yellowing, but diVerent subcellular Cl ¡ redistribution could be taking place (Fricke et al 1996;Dabuxilatu and Ikeda 2005), that is, more Cl ¡ accumulation in the vacuole of inoculated plants. Also, noninoculated plants suVered from a water deWcit whereas inoculated plants kept their RWC values similar to nonstressed plants.…”