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The effect of the micronutrient manganese (Mn) on the physiological performance of green gram [Vigna radiata (L.) R. Wilczek] under saline condition was studied in the present work. Green gram was grown under controlled conditions and treated with different concentrations of sodium chloride (NaCl): 100, 200, and 300 mM. The plant samples were analyzed from 25 to 65 days of plant growth at every 10-day interval. Significant difference was observed in leaf area index, membrane stability index, nitrate reductase enzyme activity, total chlorophyll, and carotenoid content in treated plants. A drastic reduction was recorded at 200 and 300 mM NaCl treated plants in the parameters. The concentration 100 mM resulted in a slight increase of the parameters. Foliar application of Mn as manganese chloride (MnCl2) was found to improve the physiological parameters in green gram at 200 and 300 mM salinity level and was useful in alleviating the detrimental effects of NaCl. [ABSTRACT FROM AUTHOR]

Maize is moderately sensitive to salt stress; therefore, soil salinity is a serious threat to its production worldwide. Here, two maize variety Kharif Shaktiman-1 and Pioneer 30 v92 were screened to understand the maize response to salt stress and its tolerance mechanisms. Difference in relative water content, membrane stability index, stomatal conductance, shoot and root fresh/dry weight has been analyzed under salinity. The effect of osmotic stress was also analyzed on the basis of accumulation of osmoprotentant like proline, glycine betaine and soluble sugar content. The gas exchange characteristics and autophagy-dependent cell death were used to analyses the physiological effects of osmotic stress at about 15 days after salt stress in maize. The results of relative water content, membrane stability index, stomatal conductance, accumulation of osomoprotectant was higher in Kharif Shaktiman-1, the autophagy-dependent cell death was less in Pioneer 30 v92, indicate that Kharif Shaktiman-1 has more salt tolerant ability than the Pioneer 30 v92. But the result of autophagy-dependent cell death showed an opposite trend, as it was higher in Kharif Shaktiman-1, indicate more cell damage in it under salinity. So molecular technique or marker based on autophagy-dependent cell death for the screening of stress tolerant trait in desired crop may act as method of choice. [ABSTRACT FROM AUTHOR]

In attention to wheat importance in people nutrition and wide distribution of salt agricultural lands, bread wheat variety of karaj3 were aeroponicaly way grown to investigate weak and power points in response to salinity. After growing the seedlings as 4 -5 leaf stage, they were exposed to salt stress, 200 mM NaCl. Then, rapid chlorophyll a fluorescence, activities of enzymes involving plant defense mechanisms, indices related to oxidative stress and membrane stability index were measured. The obtained results displayed that total superoxide dismutase activity and its isozymes had no significant changes under stress conditions. In addition, activities of catalase, guaiacol peroxidase and ascorbate peroxidase were elevated under stress conditions. Hydrogen peroxide, a toxic metabolite, accumulated in leaf cells affecting by salt, though significant increasing of its scavenger enzymes. Also, significant alterations occurred for lipid peroxidation and membrane stability index by salt. Na and K values in variety of karaj3 showed that K/Na ratio was more than one, however, significant increasing of Na and high decreasing of K were found. Assessing of indices related to rapid chlorophyll a fluorescence revealed that Fv/Fm parameter has been just decreased under salt. Therefore, results showed that selection of salt tolerant varieties just by Fv/Fm index was not enough reliable and it is better to apply simultaneously other indices particularly yield index. Photosystem II was not susceptible to salinity in Karaj3 variety, too. It seems lack of increased activity of superoxide dismutase and its isozymes was the probable factor for accumulation of hydrogen peroxide and oxidative stress initiation, in spite of increased its scavenging enzymes activity.

Two wheat genotypes (Khirman and Inqalab) were used to evaluate the physiological and biochemical changes caused by presoaking of seeds with different levels of hydrogen peroxide (0, 20, 40, 60, 80 and 100 µM) against two salinity levels (0 and 100 mM NaCl). The data were recorded on membrane stability index, relative leaf water content, stomatal conductance, photosystem II efficiency and antioxidant assay. The results showed that the membrane stability index was significantly influenced by genotypes and salinity, while it was non-significantly influenced by H2O2 seed soaking concentrations. The relative water content was not affected by treatment, hence no significant effects of treatment or salinity were observed. The H2O2 seed treatment seems to protect the salt sensitive genotype Inqalab against yield reductions caused by salinity. The most important observations were protective effects of H2O2 treatment on salinity stress for stomatal conductivity. Salinity tends to decrease conductivity, while H2O2 treatment increased it. Salinity did not significantly affect Fv/Fm, but there was a significant effect of H2O2. The H2O2 treatment might strongly enhanced photosynthesis via its beneficial effect on Fv/Fm. The H2O2 signals the establishment of antioxidant activity in seeds, which persisted in the seedlings to balance the ion-induced oxidative damage. The data on antioxidant assay showed that treatment tends to reduce plant H2O2 levels, which was a significant effect. However, the data did not show any clear evidence that salt stress had caused increased levels of H2O2. On the whole, beneficial effect of H2O2 was observed on both wheat genotypes.

Soil salinity is a major problem of agriculture in Pakistan. Permanent solution of salinity problem is removal of salts by leaching and drainage whic is expensive. So research efforts should involve profitable utilization of these lands through biological approaches. Considering these observations, this study was designed with the objectives to explore changes in growth and physiological attributes of different sunflower genotypes under interactive effect of salinity and boron. Vigorous seeds of selected genotypes (two tolerant, two sensitive) were sown in gravels. One week old seedlings were transplanted to ½ strength Hoagland’s nutrients solution. Three days after transplantation the requisite salinity (control and 100 mM NaCl) and boron levels (0.05 mM B, 0.5 mM B and 1.0 mM B as H3BO3) were established in three installments. The arrangement of the experiment was split plot with three replications. The data regarding shoot and root fresh weights, relative water contents (RWC), membrane stability index (MSI), and leaf area (LA) were recorded. The results revealed that salinity and boron adversely affected the growth and physiology of sunflower genotypes with a higher effect in the case of combined stress. This study also showed that the growth reduction was more in the salt susceptible genotypes (Hysun-33, Hysun-38) than in the salt tolerant genotypes (SF-187, S-278).

One-and-a-half-year-old Kinnow plants budded on Jatti Khatti were treated with different triazole compounds in the presence or absence of NaCl. All of the NaCl damage symptoms were alleviated by the triazoles. The maximum improvement in leaf weight ratio (LWR) (40.9%), membrane stability index (MSI) (1.2-fold), and relative water content (RWC) (1.1-fold) was found in paclobutrazol (PBZ)-treated plants in the presence of NaCl. Furthermore, hexaconazole (HEX) and PBZ plants had lower accumulation of Na+in leaves while less Cl−content and maximum K+content in leaf tissues were found in PBZ-treated plants under NaCl stress condition. Thus, PBZ and/or triazole (TRZ) could be used as a potential tool to enhance salinity stress tolerance in Kinnow budded on Jatti Khatti. [ABSTRACT FROM AUTHOR]

Soil salinity is a major problem of agriculture in Pakistan. Permanent solution of salinity problem is removal of salts by leaching and drainage whic is expensive. So research efforts should involve profitable utilization of these lands through biological approaches. Considering these observations, this study was designed with the objectives to explore changes in growth and physiological attributes of different sunflower genotypes under interactive effect of salinity and boron. Vigorous seeds of selected genotypes (two tolerant, two sensitive) were sown in gravels. One week old seedlings were transplanted to ½ strength Hoagland's nutrients solution. Three days after transplantation the requisite salinity (control and 100 mM NaCl) and boron levels (0.05 mM B, 0.5 mM B and 1.0 mM B as H₃BO₃) were established in three installments. The arrangement of the experiment was split plot with three replications. The data regarding shoot and root fresh weights, relative water contents (RWC), membrane stability index (MSI), and leaf area (LA) were recorded. The results revealed that salinity and boron adversely affected the growth and physiology of sunflower genotypes with a higher effect in the case of combined stress. This study also showed that the growth reduction was more in the salt susceptible genotypes (Hysun-33, Hysun-38) than in the salt tolerant genotypes (SF-187, S-278). [ABSTRACT FROM AUTHOR]

This investigation was undertaken to compare the level of salinity tolerance of the newly bred CSR-30 basmati rice variety with that of the salinity sensitive HBC-19 and Pokkali rice varieties. Twenty-one-day-old hydroponically raised seedlings at 6 and 12 dS m−1 were investigated for growth, photosynthetic rate, chlorophyll content, ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) activity, relative water content (RWC), membrane stability index (MSI), lipid peroxidation, Na/K ratio and activities and gene expression of various isoforms of antioxidative enzymes. Salinity stress led to reduction in shoot length, leaf area, dry weight, RWC, MSI, rate of photosynthesis, chlorophyll content and Rubisco activity in all the three rice varieties. The levels of reduction in these parameters were maximal in HBC-19 followed by those in CSR-30 and Pokkali respectively. Cumulative superoxide dismutase (SOD) activity increased in Pokkali and CSR-30 in consonance with increase in salinity stress while it decreased in HBC-19. The Mn-SOD activity however, was enhanced in all three varieties in the presence of salinity stress while the activities of Fe-SOD, Cu/Zn-SOD and ascorbate peroxidase were decreased in HBC-19 when compared with CSR-30 and Pokkali. The activity of catalase (CAT) was higher in HBC-19 when compared with its activity in CSR-30 and Pokkali. The levels of gene expressions of the three isoforms of SOD ascertained by reverse transcriptase polymerase chain reaction were not necessarily indicative of the activities of the corresponding enzymes. Thus, despite the maximal enhancement in gene expression of Fe-SOD in HBC-19 in response to salinity stress, the activity of this enzyme in HBC-19 remained low. Similarly, despite a marginal increase in gene expression of Cu-Zn SOD in the three varieties, its activity was significantly higher in Pokkali and CSR-30 when compared with that in HBC-19. A significant enhancement in the activity of CAT at 12 dS m−1 in HBC-19 when compared with CSR-30 and Pokkali might confer a degree of tolerance to H2O2 stress in this variety in the presence of higher levels of NaCl at the seedling stage. [ABSTRACT FROM AUTHOR]