| Abstract: | Low concentrations of aqueous hydrogen sulfide (H2S) can stimulate growth of some crops. However, it is not clear whether H2S provides crops with only sulfur and whether other sulfur compounds have similar beneficial effects. Therefore, impacts of solutions of sodium sulfate (Na2SO4), sodium sulfite (Na2SO3), sodium sulfide (Na2S), ferrous sulfide (FeS), and H2S at 0.01–1 mM were assessed on 5-day lettuce seed germination. Results showed that 0.01 mM H2S solution significantly increased lettuce shoot elongation by 40 percent (to 43.6 mm from 31.0 mm in the control), whereas 0.1 mM increased elongation by 24 percent to 38.5 mm. Only a slight 10 percent increase was observed in 0.1 mM Na2SO4, suggesting that ameliorative impact of H2S on plant growth was not a result of providing sulfur nutrient. Other sulfur solutions, however, inhibited lettuce germination and elongation to varying extents, hinting that H2S might work as a signal molecule in regulating plant cellular activities. |
