【作者】 李红；

【导师】 龙健；

【作者基本信息】 贵州师范大学 ， 环境科学， 2022， 硕士

【摘要】 石漠化问题严重制约了喀斯特地区生态和经济的发展,开展生态恢复是治理喀斯特石漠化的核心任务。在喀斯特石漠化治理生态恢复中,碳是陆地上所有生命的基础,氮是植被恢复的重要营养元素,钙是喀斯特地区岩溶动力循环的关键元素。因此,在喀斯特地区植被生态恢复工程中,不仅要注重土壤中碳氮营养元素,还要提高对富含元素钙的关注。本研究以植物-土壤钙元素循环为主线,探明石漠化生态恢复中钙元素分布及其与碳、氮元素的关系,阐述顶坛花椒(Zanthoxylum planispinum var.dintanensis)生长对富钙岩溶土壤环境的适应,阐明石漠化恢复中植物-土壤的碳、氮、钙变化规律,为喀斯特石漠化退化生态系统的恢复提供科学依据,为钙循环研究提供基础资料。主要取得的研究成果如下:1、顶坛花椒林土壤有机碳、全氮和总钙含量为21～55 g/kg、8.4～12g/kg及40～59 g/kg,均以表层土壤0～10 cm含量较高。顶坛花椒植株全碳含量404～431 g/kg,在各部位含量排序为树枝>叶片>根>枯落物;全氮含量为26～43 g/kg,以根系含量最高,其次是叶片,在花椒各部位之间具有显著差异;总钙含量为4.1～43 g/kg,在顶坛花椒内表现枯落物>叶片>根>枝的分配规律。2、随顶坛花椒种植年限的增加,土壤、根系和枯落物碳氮含量增加,叶片中全碳含量减少,而叶片全氮含量先增后减;土壤和叶片总钙含量增加,根系和枯落物中总钙含量先增后减;树枝中碳氮钙含量无显著变化。长期种植花椒造成碳、氮、钙元素之间的不平衡,以及钙的生理调节功能的延迟反应,可能是顶坛花椒生长衰退的另一个原因。3、土壤中交换态钙、酸溶态钙和水溶态钙含量分别为1.99 g/kg、0.34g/kg和0.29 g/kg,土壤钙迁移和转化受土壤水分、全磷及全镁的影响较大。主成分分析表明喀斯特生态系统中钙同碳、氮、磷一样对土壤质量有明显的支配作用。4、顶坛花椒叶片中果胶酸钙、水溶性有机酸钙、磷酸和碳酸钙含量较高,根系中草酸钙含量较多,树枝中各形态钙含量均较少。说明顶坛花椒通过增强叶片细胞组织间的粘结、细胞膜的稳定性来增强细胞壁的刚性,同时在根系中将未及时运输至植物地上部分多余的钙进行消化来适应富钙环境,且在长期的适应性进化过程中,顶坛花椒植物各部位对钙的储存方式的多样性可能是其在高钙环境中能够生长较好的原因。5、顶坛花椒体内钙素含量与土壤中水溶态钙、交换态钙和酸溶态钙水平紧密相关,而与土壤总钙含量无显著关系,表明土壤碳氮养分含量和有效性钙水平是影响花椒体内钙素含量的主导因素。土壤全氮对顶坛花椒果胶钙、草酸钙、硝酸钙与氯化钙具有促进作用,表明土壤中氮素水平的提高可增强顶坛花椒对高钙环境的适应性。叶片全碳含量与叶片总钙呈极显著负相关关系,叶片全氮与花椒体内总钙含量间具有显著正相关关系,说明花椒在干旱恶劣环境下形成了低碳-高钙叶片建成策略;且顶坛花椒体内钙元素通过影响碳素分配、氮素有效性而影响植物光合作用及植物生长发育。更多还原

【Abstract】 The problem of rock desertification has seriously restricted the ecological and economic development in karst region,so carrying out ecological restoration is the core task of managing karst rock desertification.Carbon is the basis of all life on land,nitrogen is an important nutrient for vegetation restoration,and calcium is a key element in the karst power cycle during the ecological restoration of karstic desertification management.Therefore,it is necessary not only to focus on the carbon and nitrogen nutrients in the soil,but also to enhance the attention to the rich element calcium during the vegetation ecological restoration in the karst region.This study takes plant-soil calcium cycling as the main line of research to explore the distribution of calcium elements in the ecological restoration of rocky desertification and its relationship with carbon and nitrogen elements,to reveal the distribution characteristics of calcium elements in plants,to describe the adaptation of Zanthoxylum bungeamun var.dintanensis growth to calcium-rich karst soil environment,and to explore the change of carbon,nitrogen and calcium in plant-soil during the rock desertification restoration.It aims to provide a scientific basis for the restoration of degraded karstic desertification ecosystems and basic information for calcium cycle research.The main research achievements are as follows:1.The organic carbon,total nitrogen and total calcium contents of the soil under the Zanthoxylum bungeamun var.dintanensis ranged from 21 ～ 55 g/kg,8.4 ～ 12 g/kg and 40 ～ 59 g/kg,all of which were higher in the surface soil from0 to 10 cm.The total carbon content of Zanthoxylum bungeamun var.dintanensis plant was 404 ～ 431 g/kg,and the content in each part was ranked as branch >leaf > root > litter.Total nitrogen content ranged from 26 ～ 43 g/kg,with the highest content in root,followed by leaf,with significant differences among Zanthoxylum bungeamun parts.The total calcium content ranged from 4.1 to 43g/kg,and show the distribution rule of litter> leaf > root > branch in the Zanthoxylum bungeamun var.dintanensis.2.With the increase of years of cultivation of the Zanthoxylum bungeamun var.dintanensis,the carbon and nitrogen content of soil,root and litter were increased,the total carbon content of leaf was decreased,while the total nitrogen content of leaf was increased then decreased.The total calcium content in soil and leaf were increased,the total calcium content in root and litter was increased and then decreased;there were no significant change in carbon,nitrogen and calcium content in branch.The imbalance among carbon,nitrogen and calcium elements,as well as the delayed response of the physiological regulation function of calcium caused by long-term cultivation of Zanthoxylum bungeamun may be another reason for it growth decline.3.Soil calcium content of exchange,acid-soluble and water-soluble calcium were 1.99 g/kg,0.34 g/kg and 0.29 g/kg,which were strongly influenced by soil moisture,total phosphorus and total magnesium.Principal component analysis showde that calcium,like carbon,nitrogen and phosphorus,dominated soil quality in karst ecosystems.4.The leaf of Zanthoxylum bungeamun var.dintanensis had higher content of calcium pectate,water soluble calcium,calcium phosphate and calcium carbonate,while the root had more calcium oxalate and the branch had less calcium in all forms.It is indicated that the Zanthoxylum bungeamun var.dintanensis enhances the rigidity of the cell wall by strengthening the bond between the cell tissues of the leaves and the stability of the cell membrane,while the excess calcium that was not transported to the above-ground part of the plant in time is digested at the root,thus adapted to the calcium-rich environment.The diversity of calcium storage in various parts of the Zanthoxylum planispinum var.dintanensis during long-term adaptive evolution may be the reason why Zanthoxylum planispinum can grow better in highcalcium environments.5.The calcium content of Zanthoxylum planispinum var.dintanensis was closely related to the levels of water-soluble calcium,exchangeable calcium and acid-soluble calcium in soil,but not significantly related to the soil total calcium,which indicated that the soil carbon and nitrogen nutrient content and effective calcium level were the dominant factors for the calcium content of Zanthoxylum planispinum.Soil total nitrogen had a promoting effect on calcium pectate,calcium oxalate,calcium nitrate and calcium chloride in Zanthoxylum planispinum var.dintanensis,which indicated that the increase of soil nitrogen level can enhance the adaptation of Zanthoxylum planispinum var.dintanensis to high calcium environment.There was a significant negative correlation between leaf total carbon and leaf total calcium,and a significant positive correlation between leaf total nitrogen and total calcium in Zanthoxylum planispinum,which indicating that Zanthoxylum planispinum has developed a low carbon-high calcium leaf building strategy under the harsh environment of drought;Calcium affects plant photosynthesis and plant growth and development by influencing carbon allocation,nitrogen effectiveness.更多还原