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In the present experiment, effects of sodium hydrosulfide (NaHS), a H2S donor, on the oxidative damage, antioxidant capacity and the growth of cucumber hypocotyls and radicles were studied under 100 mmol L−1 NaCl stress. NaCl treatment significantly induced accumulation of H2O2 and thiobarbituric acid-reactive substances (TBARS) in cucumber hypocotyls and radicles, and application of NaHS dramatically reduced the accumulation of H2O2 and lipid peroxidation. However, the alleviating effects greatly depended on the concentrations of NaHS, and 400 μmol L−1 NaHS treatment showed the most significant effects. Corresponding to the change of lipid peroxidation, higher activities of antioxidant enzymes as well as the antioxidant capacity indicated as DPPH scavenging activity, chelating activity of ferrous ions and hydroxyl radical (·OH) scavenging activity were induced by NaHS treatment under NaCl stress, especially by 400 μmol L−1 NaHS treatment. With the alleviating lipid peroxidation, the amylase activities in cotyledons were increased, and the length of cucumber hypocotyls and radicles were significantly promoted by NaHS treatment under NaCl stress. Unlike the effects of NaHS, pretreatment with other sodium salts including Na2S, Na2SO4, NaHSO4, Na2SO3, NaHSO3 and NaAc did not show significant effects on the growth of cucumber hypocotyls and radicles. These salts do not release H2S. Based on above results, it can be concluded that the effects of NaHS in the experiment depended on the H2S rather than other compounds derived from NaHS, and the alleviating effects might related with its function in modulating antioxidant capacity and amylase activities.

MucACP-Δ9D from cat's claw (Macfadyena unguis-cati) was ectopically overexpressed in tobacco (Nicotiana tabacum L.) leaves to increase the content of omega-7 (ω-7) fatty acids, which have nutraceutical and industrial values for polyethylene and biofuel production. Overexpressed MucACP-Δ9D localized in the plastid resulted in an increased ω-7 fatty acid (C16:1Δ9 and C18:1Δ11) content from trace level in the wild type to 25.4-29.7% in the transgenic tobacco leaves. The C16:0, C18:2, and C18:3 fatty acid content decreased by 30-50%, 24%, and 38.7% in the transgenics compared with the wild type, respectively. This evidences that the ectopically expressed MucACP-Δ9D enzyme actively converts C16:0 to C16:1Δ9. MucACP-Δ9D overexpression in tobacco had no adverse effects on any agronomic traits, including plant growth, development, or seed germination. The present findings provide an excellent germplasm resource and a new technological path for commercial production of valuable fatty acids, using high-biomass vegetative organs of a non-food crop as platforms. [ABSTRACT FROM AUTHOR]