Survey of amylose content in Secale cereale, triticum monococcum, T. turgidum and T. tauschii

A standard method for determining apparent amylose content was modified for use with samples of 2–3 cereal seeds. Starch was extracted by soaking the seeds overnight in dilute ammonia solution, grinding in NaCl solution in a microfuge tube with an appropriate pestle and decanting the starch slurry. The starch was then washed successively in acetic acid, ethanol and acetone. The amylose content was determined by dispersing 5·0 mg of the starch in ethanol, adding NaOH solution, heating until a clear gel was formed, diluting, neutralising with citric acid, staining with iodine and reading in a spectrophotometer at 620 nm. The method provided a very strong correlation with a standard method for much larger samples. The apparent amylose content was determined for 1083 accessions of Triticum monococcum (einkorn), T. turgidum (emmer), T. tauschii and Secale cereale (rye). The 10 extreme accessions of each species were re-analysed a further three times and the two most extreme individual lines were selected for genetic studies. Apparent amylose content of T. monococcum ranged from 15 to 28%; that of T. turgidum, 19–31%; T. tauschii, 21–34%; and rye 12–28%. These ranges are considered sufficiently broad to allow amylose content to be further diversified through breeding.     

COMPARATIVE STUDY OF DIFFERENT SALTS (SODIUM CHLORIDE,SODIUM SULFATE,POTASSIUM CHLORIDE,AND POTASSIUM SULFATE) ON GROWTH OF FORAGE SPECIES

Osmotic and specific ion effects are the most frequently mentioned mechanisms by which saline substance reduces plant growth. However, the relative importance of osmotic and specific ion effect on plant growth seems to vary depending on the salt tolerance of the plant under study. Tall wheatgrass (TW), perennial ryegrass (PR), African millet (AM) and Rhodesgrass (Rh) were grown in nutrient solution with sodium chloride (NaCl), sodium sulfate (Na₂SO₄), potassium chloride (KCl), and potassium sulfate (K₂SO₄) salinity up to electrical conductivity (EC) 27 dS m^?1. Growth of all plant species decreased significantly at high level (EC 27 dS m^?1) of NaCl and Na₂SO₄ salts. However, the growth of none of the plant species was affected significantly by KCl and K₂SO₄ at any level. Even leaf and shoot fresh weights were enhanced by K₂SO₄ in all plant species, except AM. Chlorine (Cl) was taken up in similar quantities from KCl and NaCl solutions and the content of the respective cations was similar to each other. Further sensitivity to sulfate and chloride was equal when sodium concentrations in shoots were equal, regardless of the anion composition of the media. The sodium (Na) concentration of the leaves of the plant species increased with increased NaCl and Na₂SO₄ levels in the nutrient solutions. The leaf Na concentration of TW was lower than that of the other plant species. However, the root Na concentration of TW was higher than that of the other plant species. Increased NaCl and Na₂SO₄ concentrations had a marked effect on leaf water potential of all plant species, and the TW showed higher leaf water potential at all levels of salts. Tall wheatgrass adjusted osmotically by accumulating electrolytes from the nutrient solution and by accumulation of glycinebetaine. Sodium was generally found more injurious than Chloride in all the four forage species. Salt tolerance could be ascribed as greater exclusion of Na ion.     

Evaluation of Salinity Effects on Ionic Balance and Compatible Solute Contents in Nine Grape (Vitis L.) Genotypes

The salinity tolerance of nine grape genotypes was studied. Salinity was applied as nutrient solutions containing 0, 25, 50, and 100 mM sodium chloride (NaCl) for two weeks. Growth was significantly reduced by salinity, whereas chloride (Cl^?) and sodium (Na⁺) contents increased. Sodium ion accumulation exceeded that of Cl^? in all treatments. Shirazi and H₆ had higher and lower Cl^? concentrations in their lamina than others. There were significant positive correlations (P < 0.01) between Cl^? and Na⁺ and negative correlation between Na⁺ and potassium (K⁺) in roots and laminas of all genotypes. Soluble sugars, proline, and glycine betaine contents increased in laminas of all of the genotypes with moderate salinity. There were positive correlations (P < 0.01) between lamina and root Na⁺ and Cl^? contents and compatible solutes in all genotypes. Overall results revealed that unlike Shirazi with higher Na⁺ and Cl^? accumulation in shoot, H₆ showed a higher capacity to restrict Na⁺ and Cl^? transport to shoot.     

Assessment of the oil content of the seed produced by <Emphasis Type="Italic">Salicornia</Emphasis> L., along with its ability to produce forage in saline soils

Soil salinity presents a serious threat to crop production. The relatively poor tolerance to this stress agent exhibited by conventional crops incentivizes the search for alternative producers of food and forage in salinity-affected environments. Halophytes belonging to the genus Salicornia L. have been suggested as being able to provide both forage and edible seed oil. Here, a set of 14 Salicornia europaea L. accessions was investigated for their ability to produce seed oil and forage in response to a range of salt concentrations (100, 300 and 600 mM NaCl) in the water used for irrigation. Seed of the accessions was collected from diverse sites close to saline rivers and the sea in Iran. Salinity was shown to have a major effect on biomass yield, and on seed oil yield and composition. The ratio of unsaturated to saturated fatty acids in the seed oil was remarkably high. Forage yield was highest when irrigated with 300 mM NaCl for most of the accessions, while a level of 600 mM NaCl suited the production of seed oil.     

Water stress induced by polyethylene glycol 6000 and sodium chloride in two maize cultivars

Responses of growth and germination to water stress induced by PEG 6000 and NaCl in two maize (Zea mays L.) cultivars 704 and 301 were studied. Water stress was generated by additions of PEG 6000 or sodium chloride to the root medium. Water potentials were: zero as control and -0.15, -0.49, -1.03 and -1.76 MPa as treatments. After 24 h treatment, the roots and shoots length and dry weight were of plants determined. In water stress, roots and shoots length and dry weight decreased at both treatments in both varieties. The germination is inversely proportional to the NaCl and PEG concentrations, it means that 704 and 301 cultivars of maize showed a reduction in germination with an increasing in NaCl or PEG concentrations induced water deficit, but this reduction in NaCl treatment were higher than PEG treatment. At treatment by PEG, the germination was severely decreased at -1.03 MPa. At treatment by NaCl no germination occurred at -1.03 in 301 var. and germination was very low at -1.03 MPa in 704 var., no germination occurred at -1.76 MPa in both varieties at both treatments. Decrease of germination in 704 variety was higher than 301 variety.     

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

Salt toxicity comprises of osmotic and ionic components both of which can severely affect root and shoot growth. In many crop species, supplemental calcium (Ca) reduces the inhibition of growth typical of exposure to salt stress. The objective of this study was to compare whole plant growth and physiological responses to interactive effect of salinity and Ca level on three forage species [African millet (AM), tall wheat grass (TW), and perennial ryegrass (PR)] differing in tolerance to sodium chloride (NaCl) salinity. Plants were grown under glasshouse condition and supplied with nutrient solution containing 0, 100, and 250 mM NaCl supplemented with 0.5, 5, or 10 mM calcium chloride (CaCl₂). Plant growth, ionic concentration, water relations, and solute (proline and glycinebetaine) concentrations of the plants were determined two weeks after the salinity treatments. At 100 mM NaCl, there was a moderate reduction in dry matter (DM) production of all three species. A drastic decrease in DM occurred at 250 mM NaCl. Supplemental Ca reduced the adverse effects of salinity on all three species. The TW showed higher shoot and root growth in 100 and 250 mM NaCl than AM and PR. It also showed the highest DM at 5 and 10 mM Ca supplement. The shoot and root DM of TW increased by about 45 and 15%, respectively compared to the control. Chemical analysis indicated that in TW, Ca restricted both uptake and transport of sodium (Na) from root to shoot. It also increased Ca and potassium (K) concentrations in both organs. The transport of K and Ca from root to shoot of AM and PR were decreased by NaCl, but were restored with increasing Ca in the medium. The opposite occurred for Na. In PR, more K uptake was observed in shoot at 250 mM NaCl with 10 mM Ca supplement. The sap osmotic potential (Ψ_S) was the highest in TW at 10 mM Ca in the presence of 250 mM NaCl. Contribution of various solutes to the difference in Ψ_S among the species from the control and 250 mM salt treatment differed greatly. Supplemental Ca induced decline in the leaf Ψ_S of TW which was predominately due to K, glycinebetaine, Na and proline accumulation. Addition of 10 mM Ca to the growth medium maintained a low Na and a high K level. Accumulation of glycinebetaine and proline in leaf contributed the NaCl tolerance of TW. The presented results suggest that supplement Ca, not only improved ionic relations but also induced plant ability in production of compatible solutes (glycinebetaine and proline) and osmotic adjustment. Accordingly, genotype dependent capacity could be found using supplemental Ca.