Influence Of Salinity Levels Research Articles

Effect of Salinity and Temperature on Seed Germination of Atriplex halimus L. (halimus and schweinfurthii subspecies) Harvested in Western Algerian Region

Background: Temperature and salinity effects on the germination and seedling growth of two subspecies of Atriplex halimus were studied in order to select the best one for the rehabilitation of degraded lands at risk of desertification. Methods: Influence of salinity levels (0, 100, 200, 300 and 400 mM) and temperature (15, 20, 25, 30 and 35°C) on seed germination of two subspecies of Atriplex halimus, halimus and Schwein furthii, were assessed. Results showed optimal germination at NaCl concentration of 100 mM that decreases above 200 mM for both subspecies. In sp Schwein furthii the germination capacity is higher at NaCl concentration of 100 mM and temperatures varying between 20 and 30°C. Result: High doses of salt (300 and 400 mM) strongly decrease the number of seeds germinated at all temperature regimes. In contrast, at temperatures between 30 and 35°C, seed germination appears to be strongly affected in sphalimus. Salinity levels of 300 and 400 mM with temperatures of 15, 20 and 35°C, reduce germination and increase mean germination time. The presence of 100 mM of NaCl in the culture medium sometimes appears to be beneficial for the growth of the seedlings. However, at high doses of salt (300 and 400 mM), length, fresh and the dry weight of the seedlings are reduced.

Initial Development of Safflower Submitted to Irrigation Water Salinity Levels

Safflower cultivation is an alternative to tropical cropping systems, with a good rusticity and some tolerance to saline stress in some cultivars. With the increase of irrigated areas around the world, salinization of the soil is an inherent concern, being the management of irrigation and cultivated species fundamental. The objective of this study was to evaluate the growth and initial development of safflower culture submitted to irrigation water salinity levels. The experiment was carried out in a greenhouse in a completely randomized design consisting of five irrigation water salinity levels (0, 2, 4, 6 and 8 dS m-1) and six replications. The saline solution was prepared using NaCl and measured with a conductivity meter. Plant height, number of leaves and stem diameter at 26 and 41 days after emergence, and shoot dry weight were evaluated; root volume; root dry mass; total dry mass and dry root/shoot mass ratio at 41 days after plant emergence. There was no visual influence of salinity levels in the evaluations at 26 days after plant emergence. However, 41 days after plant emergence, the increase in salinity levels promoted a decrease in all analyzed variables, except for root volume. Safflower does not tolerate irrigation with saline water. The damages occur from 2 dS m-1, but the largest reductions in the initial development of safflower occur from 6 to 8 dS m-1.

Influence of salinity levels on vegetative development of landrace dwarf common bean (Phaseolus vulgaris L.) Genotypes

In this study, plant growth parameters of 16 landrace dwarf common bean genotypes collected from Western Mediterranean region of Turkey at different salinity levels were investigated. The salt concentrations were applied 0.5 (regular irrigation water), 2, 4 and 6 dSm-1. The study continued until the first flowering was observed in the plants. The results of analysis of the variance revealed significant variations among different salinity levels, genotypes and interaction effects of salinity levels × genotypes for morphological characters. According to statistical analysis results, there was no correlation between stem diameter and other morphological characters. It was determined that there was a statistically significant positive strong correlation between plant height and plant dry weight (r=0.703). There was a moderately statistically significant positive correlation between all other characters. The increased salinity level negatively affected the vegetative growth of the common bean genotypes. However, low doses of salt have promoted development in some genotypes (AGB10, AGUN25, BY4, BY24, IYOZ10). However, a slight increase in salt level caused a sudden drop in development. These genotypes are thought to be suitable for soils with low salinity. The genotypes gave different responses to salt stress and ISGA1 and ISGA10 genotypes gave the best results. Besides them, prominent genotypes were detected as AGUN6, BKARA2, AGB10 and IYOZ10.

Influence of salinity level on sediment denitrification in a Louisiana estuary receiving diverted Mississippi River water

The Mississippi River water containing elevated nitrate is being diverted into Louisiana coastal estuaries to abate wetland deterioration attributed to lack of sediment and nutrients, rapid subsidence and accompanying salt water intrusion. In this study effect of salinity change on sediment denitrification at a Mississippi River freshwater diversion site (Davis Pond, Louisiana) was determined. Results show that the denitrification potential of the sediment was highest under fresh water condition (salinity close to 0‰). Addition of sea water immediately inhibited the denitrification activity of the sediment. Further analysis, by separate treatment of NaCl and K2SO4 addition, revealed that inhibition of the denitrification of the sediment by sea water was mainly caused by NaCl content in sea water. Denitrification activity of the sediment was not significantly affected by the sulfate content in sea water. Salinity increase seems a primary reason for the sediment denitrification rate decrease. A significant inverse relationship of denitrification rate and salinity was obtained [denitrification rate (mg N kg−1 day−1) = −0.20 × salinity(‰) + 10.41, R2 = 0.91]. Under highest sea water condition (salinity = 36‰), denitrification rate of the sediment would be 30.8% of its original activity (salinity = 0‰).