Silicon nanoparticles (SiNPs) restore photosynthesis and essential oil content by upgrading enzymatic antioxidant metabolism in lemongrass (Cymbopogon flexuosus) under salt stress.

Lemongrass (Cymbopogon flexuosus) has great relevance considering the substantial commercial potential of its essential oil. Nevertheless, the increasing soil salinity poses an imminent threat to lemongrass cultivation given its moderate salt-sensitivity. For this, we used silicon nanoparticles (SiNPs) to stimulate salt tolerance in lemongrass considering SiNPs special relevance to stress settings. Five foliar sprays of SiNPs 150 mg L-1 were applied weekly to NaCl 160 and 240 mM-stressed plants. The data indicated that SiNPs minimised oxidative stress markers (lipid peroxidation, H2O2 content) while triggering a general activation of growth, photosynthetic performance, enzymatic antioxidant system including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), and osmolyte proline (PRO). SiNPs amplified stomatal conductance and photosynthetic CO2 assimilation rate by about 24% and 21% in NaCl 160 mM-stressed plants. Associated benefits contributed to pronounced plant phenotype over their stressed counterparts, as we found. Foliar SiNPs sprays assuaged plant height by 30% and 64%, dry weight by 31% and 59%, and leaf area by 31% and 50% under NaCl 160 and 240 mM concentrations, respectively. SiNPs relieved enzymatic antioxidants (SOD, CAT, POD) and osmolyte (PRO) in lemongrass plants stressed with NaCl 160 mM (9%, 11%, 9%, and 12%, respectively) and NaCl 240 mM (13%, 18%, 15%, and 23%, respectively). The same treatment supported the oil biosynthesis improving essential oil content by 22% and 44% during 160 and 240 mM salt stress, respectively. We found SiNPs can completely overcome NaCl 160 mM stress while significantly palliating NaCl 240 mM stress. Thus, we propose that SiNPs can be a useful biotechnological tool to palliate salinity stress in lemongrass and related crops.

Comparative Analysis of Triterpene Composition between Ganoderma lingzhi from China and G. lucidum from Slovakia under Different Growing Conditions.

The mushroom today known as Ganoderma lingzhi has been used for centuries in the countries of Eastern Asia as a very important medicinal mushroom. It prefers growing on rotten wood of broadleaf trees and is mainly distributed in the tropics and subtropics. Its relative G. lucidum occurs naturally almost all the Earth, and it colonizes mostly oak and beech trees in Central Europe. G. lingzhi and G. lucidum are similar species. To obtain the qualitative parameters of G. lingzhi and G. lucidum, several strains (five G. lingzhi strains and five G. lucidum ones) were chosen and cultivated in both Slovakia and China, using wood chip (beech and oak) substrate and liquid fermentation method, respectively. It was found that there were more low-polarity triterpenes in G. lucidum, while G. lingzhi contained more high-polarity triterpenes. Beech substrate was more suitable for the accumulation of triterpenes in solid cultivation for both strains of G. lucidum and G. lingzhi. Strain C4 of G. lingzhi and strain K2 of G. lucidum contained higher triterpenes in either mycelium or fruiting bodies. Data in this study can help to identify these two species and bring a great benefit to the production of bioactive compounds of G. lucidum from Slovakia.