Yu Ju-hua, Zhong Ji-cheng, Fan Cheng-xin, Huang Wei, Shang Jing-ge, Gu Xiao-zhi
Huan Jing Ke Xue. 2015 Dec;36(12):4444-54.
Growth of rooted aquatic macrophytes was affected by the nature and composition of lake bottom sediments. Obviously, it has been recognized as an important ecological restoration measure by improving lake substrate and then reestablishing and restoring aquatic macrophytes in order to get rid of the environmental problem of lake. This study simulated five covering thickness to give an insight into the influence of substrate amelioration on Phragmites communis growth and photosynthetic fluorescence characteristics. The results showed that the total biomass, plant height, leaf length and leaf width of Phragmites communis under capping 5 cm were much more significant than those of capping 18 cm (P < 0.01), at the 120 d, the underground: shoot biomass ratio and fine root: underground biomass ratio were also much higher than those of other treatments (P < 0.05), which indicated that capping 18 cm treatment would significantly inhibit the growth of Phragmites communis , but the growth of control group Phragmites communis was slightly constrained by eutrophicated sediment. In addition, as the capping thickness growing, the underground: shoot biomass ratio of the plant would be reduced dramatically, in order to acquire much more nutrients from sediment for plant growing, the underground biomass of Phragmites communis would be preferentially developed, especially, the biomass of fine root. However, Photosystem II (PS II) photochemical efficiency (Fv/Fm), quantum yield (Yield), photochemical quenching (qP), non-photochemical quenching (qN) of Phragmites communis under different treatments had no significant differences (P > 0.05), furthermore, with much greater capping thickness, the photosynthesis structure of PS II would be much easier destroyed, and PS II would be protected by increasing heat dissipating and reducing leaf photosynthetic area and leaf light-captured pigment contents. In terms of the influence of sediment amelioration by soil exchange on the growth and photosynthetic fluorescence characteristics of Phragmites communis, plant growth could be effectively promoted under capping 2 cm and capping 5 cm by increasing the Eh value and nutrient content, whereas plant under capping 18 cm would be much easier adaptive to low-light stress in winter season, of which capping 2 cm treatment was conducive to enhance the initial slope of RLCs (α), maximum electron transport rate (ETRmax) and minimum saturating irradiance (Ek). With regard to the harness of environmental problem of lake, the eutrophication status of lake will be mitigated by using multi-ecological measures to control the internal nutrients content once the external loading was first effectively controlled.
水生有根大型植物的生长受到湖底沉积物性质和组成的影响。显然，通过改善湖泊底质进而重新建立和恢复水生大型植物以解决湖泊环境问题已被视为一项重要的生态修复措施。本研究模拟了五种覆盖厚度，以深入了解底质改良对芦苇生长及光合荧光特性的影响。结果表明，在120天时，覆盖5厘米处理下芦苇的总生物量、株高、叶长和叶宽均显著高于覆盖18厘米处理（P<0.01），其地下与地上生物量比和细根与地下生物量比也显著高于其他处理（P<0.05），这表明覆盖18厘米处理会显著抑制芦苇生长，但对照组芦苇生长受到富营养化沉积物的轻微抑制。此外，随着覆盖厚度增加，植株的地下与地上生物量比会大幅降低，为从沉积物中获取更多养分供植株生长，芦苇的地下生物量，尤其是细根生物量会优先发育。然而，不同处理下芦苇的光系统II（PS II）光化学效率（Fv/Fm）、量子产量（Yield）、光化学猝灭（qP）、非光化学猝灭（qN）均无显著差异（P>0.05），而且，覆盖厚度越大，PS II的光合结构越易被破坏，PS II会通过增加热耗散、减小叶片光合面积和降低叶片光捕获色素含量来得到保护。就土壤置换改良沉积物对芦苇生长及光合荧光特性的影响而言，通过提高Eh值和养分含量，覆盖2厘米和5厘米处理能有效促进植株生长，而覆盖18厘米处理的植株在冬季更易适应弱光胁迫，其中覆盖2厘米处理有利于提高快速光曲线的初始斜率（α）、最大电子传递速率（ETRmax）和最小饱和光强（Ek）。对于湖泊环境问题的治理，一旦有效控制了外部负荷，通过采取多种生态措施控制内部营养物含量，湖泊的富营养化状况将得到缓解。
