Urochondra setulosa （Trin.） C.E. Hubbard is a coastal halophytic grass thriving on the coastal dunes along the Pakistani seashore. This grass could be useful in coastal sand dune stabilization using seawater irrigat...Urochondra setulosa （Trin.） C.E. Hubbard is a coastal halophytic grass thriving on the coastal dunes along the Pakistani seashore. This grass could be useful in coastal sand dune stabilization using seawater irrigation. The purpose of this investigation was to test the hypothesis that Ca^2＋ （0.0, 2.5, 5.0, 10.0 and 50.0 mmol/L） alleviates the adverse effects of KC1, MgSO4, NaC1 and Na2SO4 at 0, 200, 400, 600, 800 and 1000 mmol/L on the germination of Urochondra setulosa. Seed germination was inhibited with increase in salt concentration with few seeds germinated at and above 400 mmol/L concentration. No seed germinated in any of the KC1 treatments. Inclusion of CaC12 substantially alleviated the inhibitory effects of all salts. Germination was higher under photoperiod in comparison to those seeds germinated under complete darkness. Among the CaC12 concentrations used, 10 mmol/L was most effective in alleviating salinity effects and allowing few seeds to germinate at 1000 mmol/L KC1, MgSO4, NaC1 and Na2SO4 solution.展开更多
Coastal sand dune ecosystems generally have infertile soil with low water-holding capacity and high salinity. However, many plant species have adapted to the harsh sand environment along the southeastern coast of Chin...Coastal sand dune ecosystems generally have infertile soil with low water-holding capacity and high salinity. However, many plant species have adapted to the harsh sand environment along the southeastern coast of China. Studying the microbial biomass in such an ecosystem can improve our understanding of the roles that microbes play in soil fertility and nutrient cycling. We investigated the differences in soil microbial biomass carbon(MBC) and nitrogen(MBN) contents and their seasonal dynamics in five forest types(a secondary forest and plantations of Casuarinas, Pine, Acacia, and Eucalyptus). The results indicated that the seasonal variations of soil MBC and MBN contents in all five forest stands were higher in spring and winter, but lower in summer and autumn. The MBC content was lower in the Casuarinas plantation than in the other plantations in the same soil layer. However, no significant differences were observed in MBN contents among the different forest types. The MBC and MBN concentrations were positively correlated with soil moisture, but negatively correlated with soil temperature. The MBC and MBN contents also decreased with increasing soil depth. Across all soil layers, secondary forest had the highest MBC and MBN concentrations. Our study also showed that the MBC and MBN contents were positively affected by total soil carbon(TC), pH, and litter N content, but were negatively impacted by soil bulk density and litter C content. Moreover, the MBN content was positively correlated with root N content. In summary, environmental factors and the differences in litter and fine roots, soil nutrient contents, as well as the soil physical and chemical properties caused by different tree species collectively affected the concentrations of the soil MBC and MBN.展开更多
基金Project supported by the 16th Pakistan-China Cooperation Project(Study on Sustainable Halophytes Utilization, No. 16-413)
文摘Urochondra setulosa （Trin.） C.E. Hubbard is a coastal halophytic grass thriving on the coastal dunes along the Pakistani seashore. This grass could be useful in coastal sand dune stabilization using seawater irrigation. The purpose of this investigation was to test the hypothesis that Ca^2＋ （0.0, 2.5, 5.0, 10.0 and 50.0 mmol/L） alleviates the adverse effects of KC1, MgSO4, NaC1 and Na2SO4 at 0, 200, 400, 600, 800 and 1000 mmol/L on the germination of Urochondra setulosa. Seed germination was inhibited with increase in salt concentration with few seeds germinated at and above 400 mmol/L concentration. No seed germinated in any of the KC1 treatments. Inclusion of CaC12 substantially alleviated the inhibitory effects of all salts. Germination was higher under photoperiod in comparison to those seeds germinated under complete darkness. Among the CaC12 concentrations used, 10 mmol/L was most effective in alleviating salinity effects and allowing few seeds to germinate at 1000 mmol/L KC1, MgSO4, NaC1 and Na2SO4 solution.
基金The Science and Technology Major Project of Fujian Province (2018NZ0001-1)The Basal Research Fund of Fujian Province Public Scientific Research Institution (2019R1009-6)+1 种基金The Casuarina Research Center of Engineering and TechnologyThe Key Laboratory of Forest Culture and Forest Product Processing Utilization of Fujian Province。
文摘Coastal sand dune ecosystems generally have infertile soil with low water-holding capacity and high salinity. However, many plant species have adapted to the harsh sand environment along the southeastern coast of China. Studying the microbial biomass in such an ecosystem can improve our understanding of the roles that microbes play in soil fertility and nutrient cycling. We investigated the differences in soil microbial biomass carbon(MBC) and nitrogen(MBN) contents and their seasonal dynamics in five forest types(a secondary forest and plantations of Casuarinas, Pine, Acacia, and Eucalyptus). The results indicated that the seasonal variations of soil MBC and MBN contents in all five forest stands were higher in spring and winter, but lower in summer and autumn. The MBC content was lower in the Casuarinas plantation than in the other plantations in the same soil layer. However, no significant differences were observed in MBN contents among the different forest types. The MBC and MBN concentrations were positively correlated with soil moisture, but negatively correlated with soil temperature. The MBC and MBN contents also decreased with increasing soil depth. Across all soil layers, secondary forest had the highest MBC and MBN concentrations. Our study also showed that the MBC and MBN contents were positively affected by total soil carbon(TC), pH, and litter N content, but were negatively impacted by soil bulk density and litter C content. Moreover, the MBN content was positively correlated with root N content. In summary, environmental factors and the differences in litter and fine roots, soil nutrient contents, as well as the soil physical and chemical properties caused by different tree species collectively affected the concentrations of the soil MBC and MBN.
