Ion Relations of Plants Under Drought and Salinity

1986 ◽  
Vol 13 (1) ◽  
pp. 75 ◽  
Author(s):  
TJ Flowers ◽  
AR Yeo
Keyword(s):  
Oryza Sativa ◽  
Osmotic Adjustment ◽  
Mature Leaf ◽  
Sensitive Species ◽  
Ion Concentrations ◽  
Ion Toxicity ◽  
Suaeda Maritima ◽  
Ion Relations ◽  
Sustained Rate

The review is primarily concerned with the ion relations of mature leaf cells of plants growing under saline conditions: during drought ions do not play such an important role in osmotic adjustment as in salinity. We conclude that, for succulent halophytes (Suaeda maritima), the demand for osmotic adjustment in the leaves matches closely (perhaps exceeds) the supply from the roots. Expanding leaves accumulate sodium at a greater rate than expanded leaves and apoplastic salt concentrations do not exceed those in the protoplast. For salt-sensitive species (Oryza sativa) supply exceeds demand, resulting in a sustained rate of xylem delivery of sodium to the expanded leaves. This in turn leads to either excessive apoplastic ion concentrations in the leaves and death through dehydration or excessive symplastic concentrations and death through ion toxicity.

Effects on Casuarina and Allocasuarina Species of Increasing Sodium Chloride Concentrations in Solution Culture

1984 ◽  
Vol 11 (6) ◽  
pp. 471 ◽  
Author(s):  
EJ Luard ◽  
MH El-Lakany
Keyword(s):  
Sodium Chloride ◽  
Osmotic Adjustment ◽  
Gradual Increase ◽  
Osmotic Shock ◽  
Turgor Pressure ◽  
Solution Culture ◽  
Height Growth ◽  
Sensitive Species ◽  
Ion Concentrations ◽  
Chloride Concentrations

Ten species of Casuarina and Allocasuarina were exposed to increasing levels of NaCl (max 550 mM) in solution culture over a period of 5 months. Na+ and Cl- ion concentrations increased in the tissues of all species as the salinity increased and K+ was selectively accumulated. Those species which ultimately survived to the highest salinities tested had lower concentrations of Na+ and Cl- in both shoot and roots and lower Na+/K+ ratios than the more sensitive species at low external salinities. Osmotic adjustment of the Casuarina species was principally accounted for by Na+ and Cl- in the shoots. Turgor pressure was not lost until the plants were close to death, so that inhibition of height growth by NaCl was probably due to the high cellular ion concentrations. Plants were more sensitive to osmotic shock than to a gradual increase in salinity.

scholarly journals Growth and Physiological Responses ofPhaseolusSpecies to Salinity Stress

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
J. S. Bayuelo-Jiménez ◽  
N. Jasso-Plata ◽  
I. Ochoa
Keyword(s):  
Salt Stress ◽  
Water Relations ◽  
Osmotic Adjustment ◽  
Soluble Carbohydrate ◽  
Salt Tolerant ◽  
Key Factors ◽  
Sensitive Species ◽  
Carbohydrate Accumulation ◽  
Unit Leaf ◽  
Salt Level

This paper reports the changes on growth, photosynthesis, water relations, soluble carbohydrate, and ion accumulation, for two salt-tolerant and two salt-sensitivePhaseolusspecies grown under increasing salinity (0, 60 and 90 mM NaCl). After 20 days exposure to salt, biomass was reduced in all species to a similar extent (about 56%), with the effect of salinity on relative growth rate (RGR) confined largely to the first week. RGR of salt-tolerant species was reduced by salinity due to leaf area ratio (LAR) reduction rather than a decline in photosynthetic capacity, whereas unit leaf rate and LAR were the key factors in determining RGR on salt-sensitive species. Photosynthetic rate and stomatal conductance decreased gradually with salinity, showing significant reductions only in salt-sensitive species at the highest salt level. There was little difference between species in the effect of salinity on water relations, as indicated by their positive turgor. Osmotic adjustment occurred in all species and depended on higher K+, Na+, and Cl−accumulation. Despite some changes in soluble carbohydrate accumulation induced by salt stress, no consistent contributions in osmotic adjustment could be found in this study. Therefore, we suggest that tolerance to salt stress is largely unrelated to carbohydrate accumulation inPhaseolusspecies.

scholarly journals Influence of Osmotic Adjustment on Leaf Rolling and Tissue Death in Rice (Oryza sativa L.)

1984 ◽  
Vol 75 (2) ◽  
pp. 338-341 ◽  
Author(s):  
Theodore C. Hsiao ◽  
John C. O'Toole ◽  
Elizabeth B. Yambao ◽  
Neil C. Turner
Keyword(s):  
Oryza Sativa ◽  
Osmotic Adjustment ◽  
Oryza Sativa L ◽  
Leaf Rolling

Effets de l'adjonction de KCl ou de CaCl2 sur la tolérance au NaCl chez deux cultivars de triticale (Clercal et Beagle)

1991 ◽  
Vol 69 (10) ◽  
pp. 2113-2121 ◽  
Author(s):  
Souheil Haddad ◽  
Alain Coudret
Keyword(s):  
Plant Growth ◽  
Key Words ◽  
Salinity Tolerance ◽  
Osmotic Adjustment ◽  
Normal Cell ◽  
Culture Medium ◽  
Selectivity Ratio ◽  
Nacl Concentration ◽  
Ion Relations ◽  
Nutrient Solutions

The effects of salinity on growth along with water and ion relations were studied on two cultivars of triticale (Clercal and Beagle) after 21 days of growth under controlled conditions in nutrient solutions with or without 150 mM NaCl, and on nutrient solutions with 150 mM NaCl + 20 mM KCl or 150 mM NaCl + 20 mM CaCl2. Growth was strongly affected by an increased NaCl concentration in the culture medium, causing a water deficit linked to a drop in water (ψ) and osmotic (π) potentials, followed by an accumulation of Na+ and a reduction of K+ in the aboveground part of the triticales. Addition of KCl or CaCl2 to NaCl-containing media improved NaCl tolerance of the plant: growth increased more than 30%, hydration of tissues improved, and K+ uptake was normal, as seen by an increased K+/Na+ selectivity ratio in the aboveground parts. The two cultivars did not show the same degree of tolerance on these media. The protection afforded by KCl or CaCl2 in the NaCl-containing media was more significant for 'Clercal' than for 'Beagle'. Moreover, it seems that in presence of KCl or CaCl2, the improved K+ uptake was greater in 'Clercal' than in 'Beagle'. It is therefore possible that 'Beagle' requires less K+ than 'Clercal' for normal cell functioning. It is suggested that the K+/Na+ selectivity ratio is critical for salinity tolerance in the triticales. Key words: NaCl, KCl, and CaCl2 tolerance, growth, water, relationships, osmotic adjustment, K+–Na+ selectivity, 'Clercal', 'Beagle', triticale.

scholarly journals Comparative impact of different iso-osmotic solutions on osmotic adjustment in Gossypium barbadense

2020 ◽  
Keyword(s):  
Osmotic Stress ◽  
Osmotic Adjustment ◽  
High Stress ◽  
Dry Weight ◽  
Gossypium Barbadense ◽  
High Yield ◽  
Specific Response ◽  
Osmotic Concentration ◽  
Ion Toxicity ◽  
Water Stress Tolerance

<p>To discriminate the specific response of ion toxicity versus osmotic stress on altering leaf solute contents, contributing of organic and/or inorganic components in osmotic adjustment and its reflection on plant performances under ionic and osmotic stresses, two cotton (Gossypium barbadense L.) cultivars, Giza 90 and Giza 83, were subjected to iso-osmotic concentration (–0.57 and –1.05 MPa) created by; NaCl, KCl and polyethylene glycol-6000. The three used osmotica altered seedling length, chlorophyll, leaf dry weight, relative water content, organic and inorganic solutes and proline. Contribution of organic solutes to osmotic adjustment tittered among the two cultivars, it was higher in PEG˃ KCl˃ NaCl in Giza 83, suggesting that the character of osmotic adjustment via salt attuned to high yield with moderate ion toxicity is effectively achieved by KCl than NaCl. At high-stress intensities, regardless to cultivar, the salt stress-induced nutritional imbalance, leaf chlorosis than osmotic stress that could be attributed to specific ion toxicity, not to osmotic stress of salt. In salt sensible cultivar only NaCl, among different osmotica, reduced leaf K+ content implying that avoidance of Na-induced K+ deficiency in leaf might stimulate salt tolerance in cotton. In our study, the capacity of plants to regulate their metabolic and physiological functions had superiority in water stress tolerance rather than osmotic adjustment.</p>

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