【作者】 李凤；

【导师】 梁士楚；

【作者基本信息】 广西师范大学 ， 植物学， 2012， 硕士

【摘要】 水生植物是湿地生态系统中能量流动和物质循环的关键环节,研究会仙喀斯特湿地的水生植物光合作用特性,对掌握会仙湿地生态系统的运转情况和健康状态,及会仙湿地植物保护和植被恢复具有重要的意义。本文通过利用水下调制荧光仪(DIVING-PAM),从诱导特性、快速光曲线和叶绿素荧光参数日变化三个方面对会仙喀斯特湿地的密刺苦草(Vallisneria denseserrulata)、五刺金鱼藻(Ceratophyllum oryzetorum)、狐尾藻(Myriophyllum verticillatum)、黑藻(Hydrilla verticillata)、马来眼子菜(Potamogeton malaianus)、石龙尾(Limnophila sessiliflora)、芦苇(Phragmites australis)、卡开芦(Phramites karka)、华克拉莎(Cladium chinense)、长苞香蒲(Typha angustata)、菖蒲Acorus calamusL.、菰(Zizania latifolia)、水蓼(Polygonum hydropiper)、丁香蓼(Ludwigia prostrata)、莲(Nelumbo nucifera)、水蓑衣(Hygrophila salicifolia)、水龙(Ludwigia adscendens)、凤眼蓝(Eichhornia crassipes)、水花生(Alternanthera philoxeroides)等19种水生植物的叶绿素荧光特性进行测定和分析,结果如下：测量19种水生植物的诱导曲线,从PS II最大光化学量子产量Fv/Fm来看,密刺苦草、五刺金鱼藻、狐尾藻、黑藻、马来眼子菜和石龙尾6种沉水植物,以及菖蒲、菰和水蓑衣3种挺水植物的Fv/Fm值小于0.8,说明这几种水生植物潜在的最大光合能力较低,而芦苇、水蓼、丁香蓼、长苞香蒲、卡开芦、华克拉莎和莲7种挺水植物,以及水龙、风眼蓝和水花生3种浮水植物的Fv/Fm值大于0.8,说明这些种类潜在的最大光合能力较高。从测量的诱导曲线得到PS II实际量子产量Y、相对电子传递速率rETR、光化学淬灭系数qP、非光化学淬灭系数NPQ随诱导时间变化而变化的曲线来看,19种水生植物的Y、 rETR和qP值开始时比较低,随后逐渐升高,最后达到稳定状态；从非光化学淬灭系数NPQ的曲线变化来看,密刺苦草、五刺金鱼藻、狐尾藻、石龙尾、芦苇、卡开芦、菰、水蓼、丁香蓼、水蓑衣、风眼蓝、水花生等种类的NPQ值在开始时比较低,很快就迅速上升,最后也达到稳定状态,而黑藻、马来眼子菜、华克拉莎、长苞香蒲、菖蒲、莲和水龙的NPQ值逐渐上升之后仍然能够保持较大的值,没有下降到达稳定状态。测量19种水生植物在光适应和暗适应条件下的快速光曲线,对曲线进行拟合,得到最大相对电子传递速率rETRmax、初始斜率α以及半饱和光强EK三个拟合参数。就同一种水生植物而言,从rETRmax来看,19种水生植物光适应后的rETRmax值都高于暗适应后的rETRmax值,说明这些水生植物经过光适应后最大光合效率都有所增加；从α来看,五刺金鱼藻、黑藻在光适应后,它们的α值比暗适应下的α值低,说明经过光适应后它们的叶片光能利用效率有所降低,其余17种水生植物经过光适应后的初始斜率α比暗适应的α值高,说明这17个种类在光适应后,光能利用效率明显提高；从EK来看,莲的EK值比暗适应的EK值低,说明莲经过光适应后,其耐受强光能力有所减弱,在光适应后,其余18种水生植物的半饱和光强EK值比暗适应的EK值高,说明其耐受强光的能力有所增强。就相同的适应条件而言,从暗适应条件来看,沉水植物中马来眼子菜、五刺金鱼藻都有较高的rETRmax和EK值,说明这两个种类具有较强的耐受强光的能力以及较高的最大光合效率；挺水植物中莲、菖蒲有较大的EK值,也有较高的最大光合效率,华克拉莎的耐受强光能力和最大光合效率都比较低,但却有最高的光能利用效率；浮水植物凤眼蓝和水花生的rETRmax、α和EK值都比较高,水龙的这三个参数的值都是最低的。从光适应条件来看,沉水植物中马来眼子菜、五刺金鱼藻、密刺苦草的rETRmax、EK的值比较高,α的值比较低,说明这三个种类具有较高的耐强光能力和最大光和效率,但其光能利用效率较低,石龙尾的光能利用效率最高,耐强光能力和最大光合效率却比较低；在挺水植物中,EK值较高的种类,其rETRmax值也会比较高,但光能利用效率较高的水生植物,其rETRmax值就比较低；浮水植物中凤眼蓝的rETRmax、α和EK值都是最高的,水龙的rETRmax、EK值是最低的。在晴天测量的19种水生植物叶绿素荧光参数的日变化中,从光合有效辐射PAR来看,19种水生植物的PAR在均呈典型的单峰型变化,中午12：30或14：30时最高,早晚较低：从rETR来看,五刺金鱼藻、狐尾藻、石龙尾、华克拉莎、水蓼、丁香蓼、莲、凤眼蓝的rETR呈单峰型变化,而其余11种水生植物的rETR都呈双峰型变化；从Y来看,19种水生植物Y的日变化是中午最低,早晚较高；从qP来看,19种水生植物qP的变化是上午随PAR的升高而下降,中午12：30或14：30时达最低,之后随着PAR的下降而逐渐上升；从NPQ来看,19种水生植物NPQ的变化是上午随着PAR的增大而逐渐升高,PAR最大时,NPQ也到达最大,随后随着PAR的下降而下降。更多还原

【Abstract】 Aquatic plant plays a significant role in energy flowing and nutrient cycling of wetland ecosystem. To study the photosynthetic characteristics of aquatic plants matters to the protection and restoration of ecosystem in Huixian karst wetland. In this thesis, we studied chlorophyll fluorescence characteristics of19species of aquatic plants in Huixian karst wetland by usingDIVING-PAM.19species of aquatic plants included6species of submerged plants: Vallisneria denseserrulata, Ceratophyllum oryzetorum, Myriophyllum verticillatum, Hydrilla verticillaia, Potamogeton malaianus, Limnophila sessiliflora,10species of emergent plants: Phragmites australis, Phramites karka, Cladium chinense, Typha angustata, Acorus calamus, Zizania latifolia, Polygonum hydropiper, Ludwigia prostrate, Nelumbo nucifera, Hygrophila salicifolia, and3species of floating plants:Ludwigia adscendens, Eichhornia crassipes, Alternanthera philoxeroides. The results were as follows.First, we measured the chlorophyll fluorescence induction curves of19species of aquatic plants in situ and found the Fv/Fm(maximal quantum yield of PS Ⅱ in the dark) showed significant differences. The Fv/Fm of6spices of submerged plants, and A. calamus, Z. latifolia, H. salicifolia were lower than0.8. The rest aquatic plants’Fv/Fm were larger than0.8, so they shall be in good physical status, and had obvious potential photosynthetic capacity.The Y (effective quantum yield), the rETR (relative electronic transfer rate) and the qP (photochemical quenching) of the19species of aquatic plants from the induction curves showed the same variation trend, rising and then to keep steady state as the time changed. And the NPQ (non-photochemical quenching) of H. verticillata, P. malaianus, C. chinense, T. angustata, A. calamus, N. nucifera and L. adscendens kept the high quantities after rising and did not dropt, while the rest aquatic plants’NPQ were rising and then downing to the steady state.Secondly, we compared the fitting parameters, rETRmax (maximal relative electron transport rate), a (initial slop of RLC) and EK(half-saturation light intensity) by fitting the rapid light curves of the aquatic plants under the condition of light adaptation and dark adaptation in situ. The results showed that rETRmaxof19species of aquatic plants under the condition of light adaptation were larger than under the condition of dark adaptation, this illustrated the increasing of the maximum photosynthesis rate after light adaptation. The a of C. oryzetorum and H. verticillata under the condition of light adaptation were lower than under the condition of dark adaptation, this illustrated the decreasing of the light use efficiency after light adaptation, while the rest17species of aquatic plants’light use efficiency increased, because their a were larger under the condition of light adaptation. The EK of N. nucifera under the condition of light adaptation was lower than under the condition of dark adaptation, this illustrated the decreasing of intensive-light tolerant capacity after light adaptation, and the rest18species of aquatic plants’ EK were larger under the condition of light adaptation, therefore their intensive-light tolerant capacity increased after light adaptation.Under the condition of dark adaptation, Potamogeton malaianus and Ceratophyllum oryzetorum had stronger intensive-light tolerant capacity and higher maximum photosynthesis rates than other stutied submerged plants. N. nucifera and A. calamus had larger EK and maximum photosynthesis rate, and C. chinense had lower EK and potential maximum photosynthetic raie but highest light use efficiency, compared with other studied emergent plants. E. crassipes and A. philoxeroides had larger rETRmax、a and EK, among the3species of floating plants, so they had stronger photosynthetic capacity than L. adscendens.Under the condition of light adaptation, P. malaianus and C. oryzetorum had stronger intensive-light tolerant capacity and higher potential maximum photosynthetic rate but lower light use efficiency than Vallisneria denseserrulata, M. verticillatum, H. verticillata and L. sessiliflora. L. sessiliflora had higher light use efficiency but lower intensive-light tolerant capacity and maximum photosynthesis rate than other stutied submerged plants. The species of emergent plants, which had larger EK, had larger rETRmax, while the species had higher light use efficiency, it would have lower rETRmax. E. crassipes had the largest rETRmax、a and EK among the3species of floating plants, and L. adscendens had the lowest rETRmax and EK.Thirdly, we studied the diurnal variations of chlorophyll fluorescence of the19species of aquatic plants in sunny days. The results showed that the diurnal variation process of PAR (photosynthetic active radiation) was fit to the single peak curve, being largest at12:30or14:30and much lower in the morning and evening. As the PAR changed, the diurnal variations of NPQ showed the same performance with PAR. The diurnal variations of rETR of C. oryzetorum, M. verticillatum, L. sessiliflora, C. chinense, P. hydropiper, L. prostrate, N. nucifera and E. crassipes were fit to single peak curves, and the rest11species of aquatic plants’ were fit to the twin peaks curves. The Y and qP of19species of aquatic plants were lowest at12:30or14:30and much larger in morning and evening, while the NPQ of the studied aquatic plants were largest at noon and lower at moring and evening.更多还原