The amelioration of salt stress-induced damage in fenugreek through the application of cold plasma and melatonin.

Nowadays, it is increasingly crucial to combine innovative approaches with established methods to enhance plant tolerance and maximize the production of beneficial compounds. With this aim in view, a study was carried out to investigate how different melatonin concentrations (0, 30, and 60 ppm), cold plasma treatment (at 3000 and 4000 V), and varying exposure durations (0, 1, 2, and 4 min) affect the physiological and biochemical attributes of fenugreek plants, as well as the levels of diosgenin under salinity stress. This study revealed that the application of 3000 V cold plasma for 2 min with 60 ppm melatonin by establishing cellular redox homeostasis in salinity-treated fenugreek plants, effectively prevented the destruction of pigments and reduced the electrolyte leakage index of malondialdehyde content. The utilization of these two elicitors has the potential to trigger multiple pathways, including the enzymatic and non-enzymatic antioxidants biosynthesis, and abscisic acid-dependent pathways. This activation results in an enhanced production of abscisic acid, auxin, and endogenous melatonin, along with the regulation of signal transduction pathways. Surprisingly, applying these two treatments increased the expression of SQS, CAS, SSR, BGL, SEP, SMT, and diosgenin content by 13, 22.5, 21.6, 19, 15.4, 12, and 6 times respectively. The findings highlight the intricate interplay between these treatments and the positive impact of their combined application, opening up avenues for further research and practical applications in improving plant tolerance to environmental stresses.

Does co-inoculation of mycorrhiza and Piriformospora indica fungi enhance the efficiency of chlorophyll fluorescence and essential oil composition in peppermint under irrigation with saline water from the Caspian Sea?

Symbiotic associations with endophytic fungi are ecologically important for medicinal and aromatic plants. Endophytic fungi highly affect the quantity and quality of herbal products. In this study, a pot experiment was carried out in the greenhouse to investigate the interactive effects of Piriformospora indica and arbuscular mycorrhizal (AMF) inoculation on the chlorophyll fluorescence, essential oil composition, and antioxidant enzymes of peppermint under saline condition. The results showed that Fo, YNPQ, YNO, and NPQ values were obviously increased under salinity conditions, while essential oil content, chlorophyll a and b, gs, Fm, Fv, ETR, ФPSII and Fv/Fm ratio decreased by increasing salinity. In addition, salt induced the excess Na+ uptake, whereas the opposite trend was observed for P and K+. The synergistic association of P. indica and AMF caused a considerable increase in the antioxidant ability, essential oil content, Fv/Fm ratio, ФPSII, and amount of P and K+ uptake in salt-stressed plants. The main peppermint oil constituents, menthol, menthone, and 1,8-cineole increased considerably in inoculated plants. Besides, the applied endophytic fungi positively enhanced the ability of peppermint to alleviate the negative effect of the salinity stress.