摘要
天津芦苇(Phragmites australis)沼泽具有重要的生态功能。目前天津地区水体咸化、氮污染和水资源短缺问题严重,显著影响了芦苇湿地的植物生理生态过程。植物稳定碳同位素组成(碳稳定同位素比值(δ13C))能够记录与植物生长过程相关联的环境变化信息,反映植物对环境变化的生理生态适应特性。该研究调查了天津七里海、北大港和大黄堡湿地芦苇叶片的δ13C分布特征,探讨了影响该地区叶片δ13C值变化的主要因素。研究表明:1)天津芦苇湿地植物叶片δ13C的变化范围在–26.3‰––23.6‰之间,平均值为–25.8‰;2)芦苇叶片δ13C与底泥相对含水量呈显著负相关关系,与底泥有效氮和全氮含量呈显著正相关关系,而与底泥盐度和磷含量没有显著相关关系;水分条件和底泥氮营养状况是影响叶片的δ13C值变化的主要因素;3)淹水条件下,芦苇叶片δ13C与叶片质量氮含量呈显著正相关关系,与叶碳氮比呈显著负相关关系,8月份七里海湿地干涸打破了此相关关系。当前环境压力下,天津沼泽湿地干涸极大地改变了芦苇的氮、水平衡和植物对水、氮资源的利用策略,而湿地干涸对该过程的影响要高于盐度和氮负荷增加。
Aims Phragmites austral marshes in Tianjin play an important role in ecosystem functioning. Wetlands of Tianjin municipality have been suffering from serious nitrogen loading, salinization and water shortage. The foliar stable carbon isotope ratio （δ13C） is a good parameter which records environmental change information associated with the plant growth process, and reflects physiological and ecological responses of plants to environment changes. The objective of this study is to investigate the effects of environment stress on the leaf δ13C of P. aus- tralis in marsh wetlands in Tianjin municipality. Methods This study was conducted in Qilihai, Beidagang, and Dahuangpu marsh wetlands. We investigated the foliar δ13C of P. australis and sediment properties, and evaluated the relationships between the foliar δ13C and sediment environmental factors. Important findings 1） Foliar δ13C ranged from -26.3‰ to -23.6‰, with an average value of-25.8‰. 2） Sediment water and nitrogen status were the important factors affecting reed foliar δ3C. Foliar δ3C was negatively correlated to sediment relative water content, and positively correlated to sediment total nitrogen and available nitrogen content. In contrast, foliar δ3C was not significantly correlated to sediment salinity and phosphorus con- tent. 3） Leaf δ13C were significantly positively correlated with leaf nitrogen content, and negatively correlated with leaf carbon and nitrogen ratio across all site. However, these relationships were not detected due to the wet- land drainage at Qilihai site in August. Wetland drainage changed the plant water and nitrogen balance, and fur- ther affected water and nitrogen utilization strategies of P. australis. Moreover, wetland drainage had stronger effects on these processes than nitrogen loading and salinization.
出处
《植物生态学报》
CAS
CSCD
北大核心
2015年第11期1044-1052,共9页
Chinese Journal of Plant Ecology
基金
天津市应用基础与前沿技术研究项目(15JCQNJC08100)
天津市高等学校创新团队培养计划"天津海岸带水资源与区域生态环境变迁研究"(TD12-5037)
天津师范大学校博士基金项目(52XB1209)
关键词
碳稳定同位素比值
氮
盐度
湿地干涸
芦苇
stable carbon isotope ratio, nitrogen, salinity, wetland drainage, Phragmites australis
