• 关键词：氮输入  水淹  光合特性  短叶茳芏  闽江河口湿地

• 基金项目：福建省自然科学基金（No.2015J01161）；福建省公益类科研院所专项（No.2017R1034-6）；福建师范大学亚热带河口生物地球化学创新团队项目（No.IRTL1205）

• 张林海
• 1. 福建师范大学地理科学学院, 福州 350007;2. 福建师范大学亚热带湿地研究中心, 福州 350007;3. 湿润亚热带生态地理过程教育部重点实验室, 福州 350007

• 曾从盛
• 1. 福建师范大学地理科学学院, 福州 350007;2. 福建师范大学亚热带湿地研究中心, 福州 350007;3. 湿润亚热带生态地理过程教育部重点实验室, 福州 350007;4. 福建师范大学地理研究所, 福州 350007

• 仝川
• 1. 福建师范大学地理科学学院, 福州 350007;2. 福建师范大学亚热带湿地研究中心, 福州 350007;3. 湿润亚热带生态地理过程教育部重点实验室, 福州 350007;4. 福建师范大学地理研究所, 福州 350007

• 摘要：由于人类活动导致的外源氮（N）输入增加强烈影响着河口湿地生态系统.本研究采用中型生态系方法，以闽江河口潮滩湿地主要土著种短叶茳芏（Cyperus malaccensis）为研究对象，探讨不同外源N输入水平（0、8和16 g·m^-2·a^-1）和水淹（短时水淹和中度水淹）对短叶茳芏的生长和光合特性的影响.结果表明，实验6个月后，短时水淹的地上、地下生物量显著高于中度水淹（p<0.05）；N输入主要通过提高光饱和点（LSP）和叶绿素相对含量（SPAD值），同时降低暗呼吸速率（R_d值），提高光合性能，进而显著提高植物的生物量.短叶茳芏各个生长期净光合速率（P_n）日变化与胞间CO₂浓度（C_i）日变化大致相反，短时水淹在各个生长期P_n日变化都为"单峰"曲线，中度水淹则在第15个月变为"双峰"曲线，出现明显的"光合午休"现象.N输入增强条件下，非气孔因素是短叶茳芏植株日均P_n值显著提高的重要光合生理因素.

• Abstract：Exogenous nitrogen (N) enrichment resulting from human activity, can strongly influence the estuarine ecosystems. In this study, using mesocosm method, we examined the effects of nitrogen input (0, 8 and 16 g·m^-2·a^-1) and inundation degree (short-time inundation and moderate-inundation) on the growth and photosynthetic characteristics of Cyperus malaccensis in the Min River estuarine wetland. The ground and underground biomass of C. malaccensis in short-time inundation treatments were significantly greater than that of moderate-inundation after six months of experiments(p<0.05). The biomass and fixation of photosynthetic carbon in C. malaccensis increased significantly after nitrogen input, mainly due to the increase of light saturation point (LSP) and relative chlorophyll content (SPAD), and the drop of dark respiration rate(R_d). Diurnal variation of net photosynthetic rate (P_n) opposited to the variation of the intercellular CO₂ concentrations (C_i) in the growth period. Diurnal variation of P_n presented a single-peaked curve at all the period of crop-rotation of C. malaccensis in short-time inundation treatment, but also appeared a typical bimodal curve in accompany with the obvious midday depression of photosynthesis in the moderate-inundation treatment after fifteen months. We also found that the non-stomatal factors were the most important photosynthetic and physiological controlling factors for the increasing of diurnal mean values of P_n in nitrogen input addition treatment.

• Key words：nitrogen input  water inundation  photosynthetic characteristics  Cyperus malaccensis  Min River estuary

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