三峡库区消落带适生植物固碳释氧能力研究

固碳释氧是植物的一项重要生态功能,三峡库区消落带分布范围广、面积大,对其适生植物的固碳释氧能力进行研究具有重要的意义。以重庆市三峡库区开州区至万州区消落带13种适生植物为研究对象,通过测定其净光合速率和叶面积指数,分析研究其固碳释氧能力。结果表明,13种适生植物的净光合速率日变化曲线主要呈单峰型或双峰型曲线,单峰型曲线植物有桑(Morus alba)、白芒(Miscanthus sinensis)和辣蓼(Polygonum hydropiper),其他10种植物中山杉(Taxodium‘Zhongshanshan’)、竹柳(Salix sp.)、柑橘(Citrus reticulata)、牡荆(Vitex negundo var.cannabifolia)、地桃花(Urena lobata)、苍耳(Xanthium sibiricum)、芦苇(Phragmites australis)、大狼杷草(Bidens frondosa)、鬼针草(Bidens pilosa)、合萌(Aeschynomene indica)的净光合速率日变化曲线均表现为双峰曲线,单位叶面积日净同化量为90.28～410.20 mmol/(m~2·d),固碳量为3.18～14.44 g/(m~2·d),释氧量为2.31～10.50 g/(m~2·d);单位土地面积日固碳量为6.15～65.47 g/(m~2·d),释氧量为4.48～47.62 g/(m~2·d)。单位叶面积固碳释氧能力聚类分析表明,乔木(3种)、灌木(3种)均分为两级,草本(7种)分为三级;单位土地面积固碳释氧能力分析表明,乔木(3种)、灌木(3种)和草本(7种)均分为两级;日固碳释氧能力较强的乔木为竹柳,灌木有地桃花和牡荆,草本有芦苇、辣蓼、鬼针草。本研究为三峡库区消落带生态修复工程中植被的选择应用提供了理论参考,为消落带修复工程示范区生态效益的评价提供了科学依据。

Carbon Fixation and Oxygen Release Capabilities of Common Plants in the Water-level-fluctuation Zone of Three Gorges Reservoir

Carbon fixation and oxygen release(CFOR)is an important ecological service of the plants. Taking 13 species of optimum plants in the Water-level-fluctuating Zone of Three Gorges Reservoir in Chongqing as the research object, the net photosynthetic rate and leaf area index were measured to study the ability of carbon fixation and releasing oxygen. The results indicated that the diurnal change curve of net photosynthesis rates of 13 experimental species has one or two peaks. The daily net assimilation, carbon fixation and oxygen release capabilities of plants tested per unit leaf area was respectively 90.28 ~ 410.20 mmol/(m2.d), 3.18 ~ 14.44 g/(m2.d), 2.31 ~ 10.50 g/(m2.d). The daily carbon fixation and oxygen release per unit land area was respectively 6.15 ~ 65.47 g/(m2.d), 4.48 ~ 47.62 g/(m2.d). According to cluster analysis results,the CFOR capabilities per unit leaf area of 3 arbors are divided into two levels,3 shrubs divided into two levels,and 7herbs divided into three levels. The CFOR capabilities per unit land area of 3 arbors are divided into two levels, 3shrubs divided into two levels, and 7 herbs divided into two levels. Therefore, in order to enhance the CFOR capabilities of the vegetation system in the rural-urban fringe, not only should the plants which have higher capabilities of CFOR be chosen, but also they should be configured properly through composite model. For daily carbon storage and oxygen release capabilities, the higher arbor is Salix, the higher shrubs are Vitex negundo var. cannabifolia, Urena lobata, the higher herbs are Phragmites australias, Polygonum hydropiper, and Bidens pilosa. The study was expected to provide theoretical reference for the selection and application of vegetation in the ecological restoration project of the Water-level-fluctuating Zone of the Three Gorges Reservoir Area, and to provide a scientific basis for the evaluation of the ecological benefits of the Water-level-fluctuating Zone demonstration project.