湿地植物根系对水盐生境异质性的适应机制研究进展 ——以黄河三角洲滨海湿地为例

Root system is the most important bridge connecting the above-ground and underground ecosystems, and plays an im portant role in the energy flow and material circulation of ecosystems. Heterogeneous environment caused by intense water-salt exchange in coastal wetlands is one of the most important factors affecting the structure and function of plant roots. This paper reviewed the re search progress of water and salt stress on wetland plant root system in the past few years, previous studies focused on the response mechanism of plant roots under constant stress simulation, however, the heterogeneous habitat characteristics in nature was ignored. The research on plant adaptation to habitat heterogeneity is mostly focused on the acquisition of resources by roots, but the research on root response mechanism in heterogeneous stress habitats is still scarce. The coastal wetlands in the Yellow River Delta have the characteris tics of river-sea interaction, land-sea transition and newly-formed. It is natural ideal experimental site for studying the root response mechanism under the condition of habitat heterogeneity. However, there are few studies on plant roots in the coastal wetlands of the Yellow River Delta. Based on the research progress of plant root of coastal wetlands in the world, three aspects of future research on root ecology of coastal wetlands in the Yellow River Delta were suggested: 1) Effects of time heterogeneity of water and salt on vegetation of coastal wetlands; 2) the relationship of clonal integration of root system and community and ecosystem under heterogeneous habitat; 3) root response of wetland clonal plants to climate changes.</p

重度盐渍化湿地土壤酶活性对生物炭添加及浅翻处理的响应

The effects of biochar adding and ploughing on heavily salinized soil were studied in the coastal wetland of the Yellow River Delta.The changes of soil physio-chemical parameters and soil enzyme activities were analyzed under different treatments,and the improvement effects of ploughing and biochar addition on severely salinized soil were discussed.Compared with the control group,the ploughing treatment increased the soil surface conductivity,but did not significantly change the soil bulk density,water content and total carbon content.However,the high amount of biochar adding treatment significantly reduced the soil bulk density,and increased total carbon and organic matter content.The activity of sucrase did not significantly changed by ploughing treatment,but after adding the medium or high amount of biochar,the activity of sucrose increased significantly.In conclusion,biochar addition could increase soil enzymes in a short time,which could be helpful for soil improvement of heavily degraded saline wetland.</p

Effect of Biochar Addition and Ploughing on Soil Enzyme Activities in Heavily Degraded Saline Wetland

The effects of biochar adding and ploughing on heavily salinized soil were studied in the coastal wetland of the Yellow River Delta. The changes of soil physio-chemical parameters and soil enzyme activities were analyzed under different treatments, and the improvement effects of ploughing and biochar addition on severely salinized soil were discussed. Compared with the control group, the ploughing treatment increased the soil surface conductivity, but did not significantly change the soil bulk density, water content and total carbon content. However, the high amount of biochar adding treatment significantly reduced the soil bulk density, and increased total carbon and organic matter content. The activity of sucrase did not significantly changed by ploughing treatment, but after adding the medium or high amount of biochar, the activity of sucrose increased significantly. In conclusion, biochar addition could increase soil enzymes in a short time, which could be helpful for soil improvement of heavily degraded saline wetland

Study on the differences of root spatial distribution characteristics of Phragmites australis in two different water-salt habitats in the Yellow River Delta

In order to study the growth differences of Phragmites australis, especially the differences of root ecological characteristics, between the tidal and fresh water habitats of the Yellow River Delta, two typical habitats of P. australis in tidal and fresh water habitats were chosen, and the electrical conductivity (EC) and pH of different soil layers were measured; the height, density, biomass of stem, leaf, main and fibrous root and ion content in different soil layers of P. australis were also analyzed. The results showed that the EC of surface soil (0-10 cm) was higher than that of the lower soil in both habitats and the minimum EC was tested in 20-30 cm soil layer. However, with the increase of soil depth deeper than 20-30 cm, the EC value increased and the pH decreased. The mean density and height of P. australis were (20.805.93) stem·m~(-2) and (35.7016.01) cm in tidal area, (309.60 39.15) stem·m~(-2) and (91.48 13.09) cm in fresh water habitat, separately. In terms of biomass allocation, the proportion of the main root, fibrous root, stem and leaf of P. australis in tidal and fresh water habitats were 79.70%, 11.88%, 6.79%, 1.64% and 66.77%, 8.76%, 18.54%, 5.92%, respectively. The main and fibrous root biomass of P. australis in fresh water habitat was mainly concentrated in 0-30 cm and 0-10 cm(68.1838.99) g·m~(-2) soil layer, respectively. And the main root biomass of P. australis in tidal water area was mainly concentrated in 20-3 0cm (146.57109.94) g·m~(-2) soil layer. After analyzing the ion content of roots in two habitats, we found the average content of Na~+ and K~+ in the main root of P. australis from tidal water habitat were (6.381.56) mg·g~(-1) and (1.080.17) mg·g~(-1) respectively, and the distribution of Na~+ and Cl- had a significantly positive correction (P<0.01). The average contents of these two ions in the main root of P. australis in fresh water habitat were (2.820.56) mg·g~(-1) and (3.931.10) mg·g~(-1) respectively. The results show that P. australis can adjust the height, density and biomass allocation of different organs and the distribution of ions to adapt to the different salt-water environment, which is the typical adaptation mechanism of P. australis in high-salt areas