Efectul stresului salin asupra germinației semințelor și a conținutului de clorofilă a plantulelor la unele populații locale de tomate (Lycopersicon esculentum Mill.)

Soil salinity is one of the most important abiotic stress factors affecting the global food security. The impact of salt-affected soils on plant productivity is sometimes disastrously. This requires the identifying and creating new plants genotypes tolerant to osmotic stress. These activities are difficult because the physiological, biochemical and molecular mechanisms responsible for the growth reduction of crops is not completely understood. In the effort to increase plant resistance to salinity, special attention should be given to local landraces as important genetic resources. The aims of the present study were to contribute to a better understanding of the physiological mechanisms involved in salt stress tolerance of Lycopersicon esculentum Mill. plants, especially during seed germination and seedlings growth and to identify the local landraces tolerant of salts excess. The results show that all from the tested cultivars represent a valuable germplasm source useful for improvement of the salinity resistance in the tomato plants

Comportamentul unor populatii locale de ceapă (Allium cepa L.) sub influenta stresului salin

Soil salinity is a very important ecological factor that affects the growth and the yield of cultivated plants, especially in arid and semi-arid regions. This decrease in land productivity due to salinization, come in contradiction with increased food need. In the effort to create plants resistant to salinity, exploitation of diverse sources of variability as local landraces is required. Onion (Allium cepa L.) is a very important vegetable crop considered salt sensitive. The aim of this work was to determinate the effect of salt stress of 11 landraces collected from NE Romania, in Iasi and Botosani districts in areas with saline excess. The results of research show that only some of the studied cultivars reacted to salt stress according to the biphasic model Munns. Only one of this local landraces presented a better salt resistance expressed by high chlorophyll content and a yield close to the control variant

The Impact of Salinity Stress on Antioxidant Response and Bioactive Compounds of Nepeta cataria L.

In this study, the ability of Nepeta cataria L. to grow and synthesize bioactive compounds on soil treated with different salt concentrations was tested to evaluate the opportunity of cultivating it in soils affected by salinization. N. cataria L. was grown in soil containing specific amounts of NaCl, Na2SO4, and their mixture. After harvesting, the plants were analyzed from the morphological and physiological point of view. Salinity stress inhibited the growth, with the highest decrease of the plant yield up to about 70% in the case of salt mixture, and smaller values for the separate salt treatments. In the same time, as a defense mechanism, there was an increase of granular trichomes’ density, as observed with the scanning electron microscope. For mild concentrations of salt, the amount of chlorophyll pigments was enhanced, while for stronger salinity stress, it decreased. The opposite behavior was evidenced for the polyphenol content, as antioxidant activity was used as a protective mechanism against reactive oxygen species produced under salinity stress. The antioxidant activity was considerably higher for separate NaCl and Na2SO4 treatments than for the salt mixture variants. The results showed that the species Nepeta cataria L. reacts well to high salinity levels, with an increased content of bioactive compounds and antioxidant activity even for the highest studied salinity conditions

The Impact of Salinity Stress on Antioxidant Response and Bioactive Compounds of <i>Nepeta cataria</i> L.

In this study, the ability of Nepeta cataria L. to grow and synthesize bioactive compounds on soil treated with different salt concentrations was tested to evaluate the opportunity of cultivating it in soils affected by salinization. N. cataria L. was grown in soil containing specific amounts of NaCl, Na2SO4, and their mixture. After harvesting, the plants were analyzed from the morphological and physiological point of view. Salinity stress inhibited the growth, with the highest decrease of the plant yield up to about 70% in the case of salt mixture, and smaller values for the separate salt treatments. In the same time, as a defense mechanism, there was an increase of granular trichomes’ density, as observed with the scanning electron microscope. For mild concentrations of salt, the amount of chlorophyll pigments was enhanced, while for stronger salinity stress, it decreased. The opposite behavior was evidenced for the polyphenol content, as antioxidant activity was used as a protective mechanism against reactive oxygen species produced under salinity stress. The antioxidant activity was considerably higher for separate NaCl and Na2SO4 treatments than for the salt mixture variants. The results showed that the species Nepeta cataria L. reacts well to high salinity levels, with an increased content of bioactive compounds and antioxidant activity even for the highest studied salinity conditions

Salinity Stress Influences the Main Biochemical Parameters of Nepeta racemosa Lam.

In this work, the effects of salt stress on Nepeta racemosa Lam. were studied to analyze the possibility of using it as a potential culture for salinity-affected soils. A total of nine concentrations of salts&mdash;NaCl (18, 39, and 60 mg/100 g soil), Na2SO4 (50, 85, and 120 mg/100 g soil), and a mixture (9 g NaCl + 25 g Na2SO4, 19 g NaCl + 43 g Na2SO4, and 30 g NaCl + 60 g Na2SO4/100 g soil)&mdash;simulated real salinity conditions. Environmental electron microscopy offered information about the size and distribution of glandular trichomes, which are very important structures that contain bioactive compounds. The chlorophyll pigments, polyphenols, flavonoids, and antioxidant activity were determined based on spectrophotometric protocols. The results have shown a different impact of salinity depending on the salt type, with an increase in bioactive compound concentrations in some cases. The highest polyphenol concentrations were obtained for Na2SO4 variants (47.05 and 46.48 mg GA/g dw for the highest salt concentration in the first and second year, respectively), while the highest flavonoid content was found for the salt mixtures (42.77 and 39.89 mg QE/g dw for the highest concentrations of salt in the first and, respectively, the second year), approximately 100% higher than control. From the Pearson analysis, strong correlations were found between chlorophyll pigments (up to 0.93), antioxidant activity and yield for the first harvest (up to 0.38), and antioxidant activity and flavonoid content for the second harvest (up to 0.95). The results indicate the possibility of growing the studied plants in salt-stress soils, obtaining higher concentrations of bioactive compounds