Non-saline Control Research Articles

Spike and Leaf Development of Sal‐Stressed Wheat

Drought or salt stress while the shoot apex is in vegetative stage can markedly affect spike development and decrease yields of cereal grains. This study was conducted to determine the effects of salinity on shoot apex differentiation, particularly spike and spikelet development, and the number of tillers per plant on two wheat species (Triticum aestivum L. ‘Probred’ and T. turgidum L. ‘Aldura’). Plants were grown in greenhouse sand cultures that were irrigated four times daily with modified Hoagland's solution. Two saline treatments with osmotic potentials (Ψs) of −0.45 and −0.65 MPa were imposed beginning 4 d after planting by adding NaCI and CaCI2 (5:1 molar ratio) to the base nutrient solution and were compared to a nonsaline control treatment at −0.05 MPa. Salt stress accelerated development of the shoot apex on the mainstem and decreased the number of spikelet primordia in both species. Terminal spikelet stage occurred 12 and 18 d (≈280 and 420 thermal units) sooner Aidurand Probred plants, respectively, stressed at −0.65 than at −0.05 MPa. Anthesis also occurred earlier, but tillering was delayed 3 to 4 d. Compared with −0.05 MPa, Ψs of −0.45 and −0.65 MPa decreased seed yield 38 and 54% in Aldura and 7 and 43% in Probred, respectively. These decreases resulted from fewer spikes per plant and fewer kernels per spike. Salt stress increased the phyllochron and reduced the final number of leaves initiated on the main stem. In sam, salt stress prior to and during spikelet development significantly decreased the yield potential of individual spikes of Aldura, but not of the more tolerant Probred. Salt stress decreased the yield potential of both species most by reducing the number of tiller spikes.

Factors Influencing Seed Germination in Salicornia pacifica var. Utahensis

The halophyte, Salicornia pacifica var. utahensis (Tiderstorm) Munz produces seed under high salinity conditions, and deposits its seed on saline soil. Experiments were conducted to determine the effect of salinity, temperature and growth regulators on germination. Results indicate that the seeds can germinate at very high salt concentration (5% NaCl). Germination was sensitive to the changes in temperature regimes. At higher 30–20 C, light-dark sequence, no germination occurred at 3, 4 and 5% NaCl treatments. On the other hand, 30% germination did occur at 5% NaCl treatment at a temperature regime of 15–5 C. These seeds required light for germination. Only 50% germination occurred in the non-saline control in the dark and the addition of NaCl further reduced germination. The GA3 partially alleviated the inhibitory effect of NaCl and darkness. Kinetin did not promote germination.

Effects of salinity on germination, seedling growth, and yield of melons

Four melon (Cucumis melo L.) cultivars were tested for salt tolerance at germination, seedling growth stages, and plant maturation. ‘Noy Amid’ was the most tolerant during germination, achieving 56% germination in 15,000 mg/l NaCl solution. However, this cultivar and ‘Eshkolit Ha 'Amaqim’ were relatively sensitive during the first 4 days' growth of the radicle and the hypocotyl, and the first 3 weeks' development of the seedling. Their yields were reduced under saline as compared with non-saline field conditions. In contrast, ‘Honey Dew’ and ‘Rochet’ had little or no germination in 15,000 mg/l NaCl but showed salt tolerance during seedling growth stages. Yield of ‘Honey Dew’ was unaffected by saline field conditions, and that of ‘Rochet’ was not significantly reduced from the non-saline control. Thus, selection for salt tolerance in melons appears feasible during early vegetative growth stages but not during germination.

Response of barley and wheat to phosphorus in the presence of chloride and sulphate salinity

The study was conducted in a greenhouse and under field conditions. In the greenoouse, barley was grown to maturity in pots on a sandy soil which contained 80 and 120 meq/l of chloride and sulphate dominant salts in its saturation extract, to which 0, 10, 25 and 50 ppm P were added. In the field study, wheat was grown on loamy sand soils having 0, 25, 50 and 75 kg/ha added P levels and irrigated with either Cl- or SO4-dominant saline waters (EC=15−19 mmhos/cm). The results of the greenhouse study indicated that at maturity barley straw and grain yield was significantly increased by 50 ppm of added P both on the non-saline control and the Cl-treatments. However, 25 ppm P was optimal on the SO4-treatments. The Cl content of plants was significantly decreased and S was increased with the increase in the P content of soil. A synergistic relation between the S and P content of barley shoots was observed. In the field study wheat grain yield responded significantly to P applications upto 50 kg/ha level on the Cl-site and there was no response to applied P on the SO4-site, although the former contained more Olsen's P than the latter. The results suggested that P requirement of wheat and barley was greater on Cl- than on SO4-salinity.

Plant growth regulators from species differing in salt tolerance as affected by soil salinity

The effect of soil salinity on the level of growth regulators from species differing in salt tolerance was studied. It was found that NaCl salinity, as compared to non-saline control, increased the level of growth inhibitors in the leaves of Zea mays which completely neutralized the presence of growth promoting substances. The leaves of Suaeda fructicosa growing in saline soil indicated the presenced of ‘Inhibitor-A’ and ‘Inhibitor-B’ whose growth retarding properties were similar to that of the inhibitors obtained from maize leaves. re]19750512

Ethylene Production by Citrus Leaves from Trees Grown in Artificially Salinized Plots1

Abstract We collected lemon leaves from 25 trees growing in control and artificially salinized plots at Indio, California, 4 and 6 weeks after beginning of irrigation with water carrying 5,000 ppm total salt. Chloride content of the leaves was directly correlated with their ethylene production. Leaves with visible injury from high Cl produced more ethylene than those with no visible injury from salinized plots; foliage from the latter treatment produced more ethylene than those from nonsaline control plots. The correlation coefficient was significant at odds of 19:1 at 4 weeks and 99:1 at 6 weeks.