【作者】 洪明；

【导师】 郭泉水；

【作者基本信息】 中国林业科学研究院 ， 植物学， 2011， 硕士

【摘要】 三峡库区消落带垂直落差30m,总面积349km²,其垂直落差和面积之大,在国内外库区消落带中实属罕见。库区消落带属于水域生态系统和陆地生态系统物质、能量、信息传输与转换最活跃,且最不稳定的生态脆弱带。世界高度关注三峡水利枢纽工程,其焦点在于库区消落带的生态环境问题。消落带植被建设是库区消落带生态环境治理的重要举措,筛选适生植物是消落带植被建设的核心。三峡水库“冬蓄夏排”独特的运行方式,导致消落带生境周期性的发生着“冬水夏陆”干湿交替变化,因此,筛选即能耐水淹,又能耐干旱的植物材料,是三峡库区消落带植被建设迫切需要解决的问题。本文以“十一五”期间在巫山县建立的消落带植被建设试验示范区为依托,按照不同海拔高度划分深水位区段、浅水位区段和对照区段,以试验示范区主栽植物香附子（Cyperus rotundus）、狗牙根（Cynodon dactylon）和香根草（Vetiveria zizanioioles）为对象,定位观测经历水陆生境变化后,不同海拔区段观测对象的植物种群密度、形态性状、生物量及其分配以及光合生理响应,以期为三峡库区消落带适生植物材料筛选提供科学依据。主要结论如下:（1）经历水陆生境区段香附子的种群密度、根系长度、根系数量、块茎分蘖植株数量、总生物量、地上生物量、地下生物量、地下生物量与地上生物量的比值比对照区段均有显著增加。7月份,浅水位区段比对照区段分别增加了102.95%、24.19%、45.85%、86.96%、89.57%、49.73%、108.93%、39.76%;深水位区段比对照区段分别增加了412.19%、55.63%、71.80%、175.36%、244.67%、162.10%、284.80%、46.84%。（2）狗牙根的根径、根系长度和地下生物量与地上生物量的比值比对照区段显著增加。7月份,浅水位区段分别增加了141.37%、37.16%和13.19%,深水位区段分别增加了160.72%、41.80%和48.49%。浅水位区段种群密度、一级、二级分枝节间长度显著增加,一级、二级分枝数量减少,深水位区段种群密度减少,一级、二级分枝数量显著增加。（3）香根草的平均叶片长度、最长叶片长度、地下生物量、地下生物量与地上生物量的比值比对照区段增加,总丛数、植株平均高度、植株最高高度、每丛叶片数量、总生物量、地上生物量比对照区段减少。7月份,香根草的平均叶片长度、最长叶片长度、地下生物量、地下生物量与地上生物量的比值比对照区段分别增加10.37%、5.34%、30.04%和151.71%;总丛数、植株平均高度、植株最高高度、每丛叶片数量、总生物量、地上生物量比对照分别减少41.70%、15.61%、9.34%、0.36%、10.58%和48.46%。（4）香附子的净光合速率、气孔导度、蒸腾速率均比对照显著提高。7月份,浅水位区段比对照区段分别提高了23.52%、40.67%和40.67%,深水位区段分别提高了72.74%、55.07%和31.54%。水分利用效率、表观CO₂利用效率、表观光能利用效率（5-6月）、光饱和点提高;浅水位区段和深水位区段香附子的光补偿点变化趋势不同,浅水位区段的光补偿点显著降低,深水位区段光补偿点显著提高;最大净光合速率无显著变化,表观量子效率、暗呼吸速率均显著降低。（5）狗牙根的净光合速率、气孔导度、蒸腾速率均比对照显著提高。7月份浅水位区段分别提高了106.80%、68.03%和228.75%,深水位区段分别提高了81.63%、64.81%和200.80%。6月份水分利用效率、表观光能利用效率显著高于对照区段,7月份显著低于对照区段。表观CO₂利用效率、最大净光合速率、表观量子效率、暗呼吸速率比对照区段均有提高,而饱和点、光补偿点显著降低。（6）香根草的净光合速率比对照提高了7.23%,而气孔导度降低了9.19%,但均未达到显著差异程度;蒸腾速率降低了20.75%。香根草的水分利用效率、表观CO₂利用效率、表观光能利用效率、光补偿点均有提高;最大净光合速率、表观量子效率、暗呼吸速率均无显著变化,光饱和点显著降低。（7）同未经历水陆生境变化变化区段相比较,经历水陆生境变化后,香附子、狗牙根、香根草3种草本植物均具有较高的种群密度和生物量,表明3种草本植物对三峡库区消落带水陆生境变化具有较强的适应性。加速根系生长与分蘖,增加地下生物量的分配,为水位下降后的快速生长提供营养及能量储备是3种草本植物对水陆生境变化的主要生态适应对策。（8）香附子、狗牙根的净光合速率的提高是气孔因素和非气孔因素共同作用的结果。水陆生境变化导致气孔导度增加,气孔开放程度增大,外界CO₂进入叶肉细胞的量增加,而伴随着外界CO₂进入叶肉细胞的量增加,胞间CO₂浓度反而降低,表明非气孔因素,即光合机能的提高是其光合速率提高的主要因素。香根草的净光合速率有所提高,而气孔导度下降,胞间CO₂浓度降低,表明非气孔因素,即光合机能的提高是其光合速率提高的主要原因。（9）经历水陆生境变化后,香附子对强光的适应能力提高,狗牙根对弱光的利用能力增强,虽然,香根草可利用的光照范围有所缩短,但是,未对其维持较高净光合速率造成显著影响;香附子和香根草的生长潜力未因水陆生境变化而发生改变;相反,这种水陆生境的变化对狗牙根生长潜力的发挥起到了一定的促进作用。更多还原

【Abstract】 Hydro-fluctuation belt of Three Gorges Reservoir with area of 349 km² and vertical drop 30m is rare at home and abroad, which is the most unstable ecotone where the matter, energy and information between water ecosystem and terrestrial ecosystem translate and converse most actively. Three Gorges are greatly concerned with focus on its Ecological environment changes.Vegetation construction in hydro-fluctuation belt is an important measurement to ecological environment treatment, and screening suitable plant plays the vital role on the success. With operating mode“winter storage while summer row”, the habitats in hydro-fluctuation belt of Three Gorges Reservoir are in water in winter and into land in summer alternately. Therefore, screening plants that have the tolerance to flooding and draught is urgent in vegetation construction of hydro-fluctuation belt of Three Gorges Reservoir.Located monitoring sample plots of vegetation construction experiment and demonstration areas which were set up during the“11^th five year plan”period were set up in-between different elevation sections of the hydro-fluctuation belts of the Three Gorges Reservoir at Wushan section, where population density, morphological characters, biomass and photosynthetic physiology of Cyperus rotundus, Cynodon dactylon and Vetiveria zizanioioles responding to changing flooding-drying habitats were observed. The main conclusions are as follows:（1）Compared with no flooding area, after flooding-drying habitat changes, the population density, root length, root number, the number of shooting plant per tuber, total biomass, aboveground biomass, underground biomass and underground and aboveground biomass ratio of Cyperus rotundus increased significantly. In July, Cyperus rotundus in shallow water area increased by 102.95%, 24.19%, 45.85%, 86.96%, 89.57%, 49.73%, 108.93% and 39.76% separately, while in the deep water area increased by 412.19%, 55.63%, 71.80%, 175.36%, 244.67%, 162.10%, 284.80% and 46.84% separately.（2）Compared with no flooding area, after flooding-drying habitat changes, the root diameter, root length and underground and aboveground biomass ratio of Cynodon dactylon increased significantly. In July, root diameter, root length and underground and aboveground biomass ratio of Cynodon dactylon in the shallow water area increased by 141.37%, 37.16% and 13.19% separately, and in the deep water area 160.72%, 41.80% and 48.49% separately. In the shallow water area, the population density and internode lengths of primary and secondary branching nodes increased significantly, while in the deep water area, the population density decreased significantly and number of the primary and secondary branches increased significantly.（3）Compared with no flooding area, after flooding-drying habitat changes, the average leaf length, maximum leaf length, underground biomass and underground and aboveground biomass ratio of Vetiveria zizanioioles increased by 10.37%, 5.34%, 30.04% and 151.71% separately in the shallow water area in July, while total cluster number, average plant height, maximum plant height, leaf number per cluster, total biomass, aboveground biomass decreased by 41.70%, 15.61%, 9.34%, 0.36%, 10.58% and 48.46% separately.（4）Compared with no flooding area, after flooding-drying habitat changes, Pn, Cond, Tr of Cyperus rotundus increased significantly. In July, Pn, Cond, Tr of Cyperus rotundus increased by 23.52%, 40.67% and 40.67% in the shallow water area and 72.74%, 55.07% and 31.54% in the deep water area. WUE, CUE, LUE（June to July）, LSP of Cyperus rotundus increased, LCP in the shallow water area declined significantly and in the deep water area increased significantly. There was no obvious changes in P_max of Cyperus rotundus and AQY and Rd of Cyperus rotundus declined significantly.（5）Compared with no flooding area, after flooding-drying habitat changes, Pn, Cond, Tr of Cynodon dactylon increased by 106.80%, 68.03% and 228.75% in the shallow water area and 81.63%, 64.81% and 200.80%in the deep water area. WUE and LUE of Cynodon dactylon was significantly higher in June and significantly lower in July. CUE, P_max, AQY and Rd of Cynodon dactylon increased and LSP and LCP declined significantly.（6）Compared with no flooding area, after flooding-drying habitat changes, Pn of Vetiveria zizanioioles increased by 7.23%, Cond of Vetiveria zizanioioles decreased by 9.19%, but they both did not reach the significant level. Tr of Vetiveria zizanioioles decreased significantly by 20.75%. WUE, CUE, LUE and LCP of Vetiveria zizanioioles increased. P_max, AQY and Rd of Vetiveria zizanioioles had no significantly changes, LSP decreased significantly.（7）Compared with no flooding area, after flooding-drying habitat changes, Cyperus rotundus, Cynodon dactylon and Vetiveria zizanioioles had high population density and biomass, which indicated that the 3 herbs had good adaptability to flooding-drying habitat changes which improved the restoration growth to some extent. All three herbst showed increasing in underground growth and underground biomass allocation, which indicated that flooding-drying habitat changes promoted the root growth and tillering. Increasing underground biomass allocation preparing nutrition and energy for the regrowth after flooding was the common policy of 3 herbs to flooding-drying habitat changes.（8）Increasing of Pn of Cyperus rotundus and Cynodon dactylon were the results of stomatal and nonstomatal factors. Flooding-drying habitat changes led to the Cond and the degree of stomatal opening increasing that caused the increase of external CO₂ into the leaf cells, while Ci decreased as external CO₂ into the leaf cells increase. This indicated nonstomatal factors（improving of photosynthetic function）were the main factors of improvement of Pn. Pn of Vetiveria zizanioioles increased , while the decrement of Cond and Ci of Vetiveria zizanioioles indicated nonstomatal factors（improving of photosynthetic function）were the reason of improving of Pn。（9）After flooding-drying habitat changes, the adaptability of high light intensity of Cyperus rotundushad and the efficiency of low light intensity of Cynodon dactylon was improved. Although the scope of available light of Vetiveria zizanioioles was reduced, it did not affect the high Pn. Flooding-drying habitat changes did not cause significant changes to potential production of Cyperus rotundus, while the potential production of Cynodon dactylon was improved.更多还原