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.

Soil salinity affects arbuscular mycorrhizal colonization of halophytes

In order to determine the effects of soil salinity on AM fungi colonization in halophytes, plants of semi-arid region of North-Eastern Iran were examined for their colonization in soils with different salinity levels. Roots of several halophytes were colonized and showed typical structure of AM fungi with different levels of colonization. Haloxylon aphyllum, Kochia stellaris, Halocnemum strobilaceum, Seidlitzia rosmarinus and Salsola sp. of the Chenopodiaceae and Zygophyllum eurypterum and Peganum harmala of the Zygophyllaceae were found to be colonized by AM fungi. In several species the mycorrhizal status is reported for the first time. The results of this study revealed that AM colonization in halophytes in soil with high salinity level (16 dS m(-1)), but colonization was inhibited by very high salinity (45 dS m(-1)). The AM fungi colonization was absent in halophytes in very high soil salinity conditions may was due to inability of AM fungi to survive such salinity conditions, which may limit the beneficial effects of AM fungi in halophytes.