不同地下水埋深下骆驼刺幼苗叶片生理参数光响应特性   总被引：3，自引：1，他引：2  

张晓蕾  曾凡江  刘波  张慧  刘镇  安桂香 《干旱区地理》2011,34(2):229-235

为探讨地下水位变化对骆驼刺(Alhagi sparsifolia Shap.)幼苗生长发育的影响,2008年9月在塔克拉玛干沙漠南缘绿洲外围,利用Li-6400光合作用仪测定了人工控制1,1.5,2.0,2.5 m地下水埋深下骆驼刺幼苗叶片净光合速率(Pn),蒸腾速率(Tr),水分利用效率(WUE)等生理参数对有效光辐...  相似文献   

Treating ballast water with hydroxyl radical on introduced organisms   总被引：4，自引：0，他引：4  

张芝涛  白敏菂肖宇 白敏冬杨波  白希尧 《中国海洋湖沼学报》2006,24(2):161-167

1 INTRODUCTION The introduction of invasive marine species into new environments by ship’s ballast water, by attaching to ships’ hulls or via other vectors has been recognized as one of the four major threats to the world’s oceans by Global Environment…  相似文献   

桂林潮田河水溶解无机碳昼夜变化与通量     

章程  汪进良  肖琼  郭永丽  苗迎 《地球学报》2021,42(4):555-564

小型山区河流系统具有流域面积小、响应时间短、人类活动的水化学影响易识别等特点,是研究生物地球化学过程的理想场所.本文以桂林潮田河为例,通过高分辨率监测与高频取样,研究水化学昼夜动态变化,无机碳移除及其生物地球化学控制机理.受水生光合作用与钙沉积作用的控制,河水pH、DO、SpC、HCO–3和Ca2+离子产生显著的昼夜动态变化,这些水化学指标昼夜变幅大小又与河床基质和水生植物类型有关.砾石类河床藻类发育的鸟岭桥河段Ca2+和HCO3-含量白天下降幅度平均值分别为12％和11％,泥质类河床沉水植物发育的两河沟河段为10.6％和8.9％.DO浓度与pH值主要受局地河流内部过程控制,即水生植物或藻类光合作用控制,而电导率受上游传输影响较大,滞后时间与两点之间信号平流传输时间相关.监测河段水体因光合作用产生的钙沉降与溶解无机碳移除量分别为302 kg/d和997 kg/d,即188.75 g/m/d和623.13 g/m/d,是西南亚热带典型地下河出口河流的4～5倍,小型岩溶河流沿流程发生的无机碳向有机碳转化,对水体碳通量而言,是真正意义上的自然碳汇过程.  相似文献   

Carbon sequestration and decreased CO2 emission caused by terrestrial aquatic photosynthesis: Insights from diel hydrochemical variations in an epikarst spring and two spring-fed ponds in different seasons     

《Applied Geochemistry》2015

Whether carbonate weathering could produce a stable carbon sink depends primarily on the utilization of dissolved inorganic carbon (DIC) by aquatic phototrophs (the so-called Biological Carbon Pump-BCP effect). On this basis, water temperature (T), pH, electrical conductivity (EC) and dissolved oxygen (DO) were synchronously monitored at 15-min resolution for one and two days respectively in January and October 2013 in Maolan Spring and the spring-fed midstream and downstream ponds in Maolan Nature Reserve, China. A thermodynamic model was used to link the continuous data to allow calculation of CO₂ partial pressures (pCO₂) and calcite saturation indexes (SI_C). A floating static chamber was placed on the water surface successively at all sites to quantify CO₂ exchange flux between atmosphere and water so as to evaluate the BCP effect. Results show that, in both winter and autumn, remarkable diel variations of hydrochemical parameters were present in the midstream pond where DO, pH, and SI_C increased in the day and decreased during the night while EC, $\left[{{\text{HCO}}_3}^{-}\right]$, [Ca²⁺] and pCO₂ showed inverse changes mainly due to the metabolic processes of the flourishing submerged plants, with photosynthesis dominating in the day and respiration dominating at night. However, hydrochemical parameters in the spring and downstream pond show less change since few submerged plants developed there. It was determined that the BCP effect in the midstream pond was 285 ± 193 t C km⁻² a⁻¹ in winter and 892 ± 300 t C km⁻² a⁻¹ in autumn, indicating a potential significant role of terrestrial aquatic photosynthesis in stabilizing the carbonate weathering-related carbon sink.  相似文献   

Land use effects on habitat,water quality,periphyton, and benthic invertebrates in Waikato,New Zealand,hill‐country streams   总被引：2，自引：2，他引：0  

John M. Quinn  A. Bryce Cooper  Robert J. Davies‐Colley  J. Christopher Rutherford  R. Bruce Williamson 《新西兰海洋与淡水研究杂志》2013,47(5):579-597

Water quality, habitat, and biota were compared during spring amongst c. 100 m reaches on 11 streams draining pasture, native (podocarp‐broadleaf) forest, and exotic pine forest established on pasture 15 years previously. Differences were greatest between the pasture and native forest streams. Only 1–3% of incident light reached native and pine forest streams whereas 30% reached pasture streams. Pasture streams had 2.2°C higher mean temperature than the native streams, and 5‐fold higher nitrate, 30‐fold higher algal biomass, and 11‐fold higher gross photosynthesis. Native streams were 60% wider than pasture, with pine streams intermediate. Pine and pasture streams had 3‐fold higher suspended solids and fine sediment stored in the streambed than native streams. Woody debris volume was 17‐fold greater in pine than pasture streams, with native streams intermediate. Invertebrate taxa richness did not differ between land uses. Community composition differed most between pasture and native forest, with pine forest streams intermediate. Invertebrate densities were 3‐fold higher in pasture than native streams, mainly because of more chironomids and snails, but mayflies, stoneflies, and caddisflies densities were 2–3‐fold higher in forest streams than pasture.  相似文献   

Contribution of photosynthetic gains during tidal emersion to production of Zostera capricorni in a North Island,New Zealand estuary     

Anne‐Maree Schwarz 《新西兰海洋与淡水研究杂志》2013,47(5):809-818

Photosynthetic characteristics of intertidal Zostera capricorni were measured under different tidal conditions in Whangapoua Harbour on the eastern Coromandel Peninsula, New Zealand, and compared with permanently submerged seagrass beds. Photosynthetic characteristics were measured using pulse amplitude modulated (PAM) fluorom‐etry and oxygen (O2) electrode techniques. Gross light saturated photosynthesis measured as oxygen exchange averaged 5.74 and 5.36 mg O₂ g^–1 dry weight (DW) h^–1 and leaf respiration rates averaged 1.22 and 1.38 mg O₂ g^–1 DW h^–1, for intertidal and subtidal plants respectively. Photosynthesis of both intertidal and shallow subtidal plants was light saturated at between 195 and 242 μmol photons m ^–2 s^–1, suggestive of acclimation to a high light environment. Despite the period of exposure at low tide clearly being an important time for photosynthetic gains for intertidal plants, when water clarity was sufficiently high, maximum rates of photosynthesis were also possible when the beds were submerged. If average water clarity was at the clearer end of a range measured for this site (K_d = 0.85 m^–1) then it was calculated that for intertidal seagrass beds growing at mean sea level in Whangapoua, c. 50% of above‐ground production could occur while plants were submerged.  相似文献   

干旱环境下高温对胡杨光合作用的影响   总被引：4，自引：2，他引：2  

陈亚鹏  陈亚宁  李卫红  徐长春 《中国沙漠》2009,29(3):474-479

在塔里木河下游3个地下水埋深（4.64 m,6.15 m,7.02 m）环境下,利用LI-6400便携式光合作用测定仪测定了胡杨叶片在适宜温度（27 ℃）和高温（39 ℃）下的净光合速率（Pn）、气孔导度(gs)、蒸腾速率（E）及胞间CO2浓度（Ci）,比较了不同地下水埋深下胡杨光合作用对高温的响应。结果表明：在3个地下水埋深下高温都使得光合速率和气孔导度明显减少,并且在地下水埋深（7.02 m）较深处,高温使得光合速率和气孔导度的下降幅度也最大,这都说明干旱胁迫加强了高温对胡杨光合作用的负面效应。然而,在同一地下水埋深下,由于高温的影响,胡杨叶片的胞间CO2浓度并未随着净光合速率和气孔导度的下降而减少,其原因很可能是气孔发生了不均匀关闭。而叶片的蒸腾速率和饱和水汽压由于高温作用的影响都明显增加,并且在地下水埋深7.02 m处,高温引起蒸腾速率的增加幅度是最小的,这表明了气孔对干旱高温胁迫下胡杨的光合作用具有一定调节作用。  相似文献   

NaCl胁迫对甜瓜叶片气体交换和叶绿素荧光特性的影响   总被引：6，自引：6，他引：0  

陈年来  张玉鑫  安黎哲 《中国沙漠》2009,29(6):1129-1133

以两个变种甜瓜幼苗为材料,在人工控制条件下研究了NaCl胁迫对甜瓜叶片气体交换和叶绿素荧光特性的影响。结果表明,盐胁迫降低了甜瓜叶片光合色素含量、净光合速率、蒸腾速率、气孔导度和PSⅡ最大光化学效率、PSⅡ潜在活性、PSⅡ电子传递量子效率和光化学猝灭系数,使非光化学猝灭系数升高。在≤50 mmol·L-1 NaCl胁迫下,甜瓜叶片光合速率降低主要由气孔因素引起,而在NaCl浓度≥100 mmol·L-1条件下则以非气孔限制因素为主。  相似文献   

祁连山地区不同植被生态系统固碳价值量估算及时空演变分析     

曾攀儒  张福平  冯起  魏永芬  黄良红  李玲 《冰川冻土》2019,41(6):1348-1358

基于改进的CASA模型测算祁连山地区植被净初级生产力（NPP）物质量, 并进一步基于光合作用方程式、 碳循环过程模型估算了研究区2005年、 2010年、 2015年植被、 土壤固碳量及价值, 旨在定量分析该区域不同植被生态系统植被、 土壤固碳价值时空演变情况, 为制定更科学合理的碳管理措施提供科学依据。研究表明： 祁连山地区2005 - 2015年植被、 土壤固碳价值呈递增趋势, 2005年、 2010年、 2015年植被、 土壤固碳价值分别为515.95、 356.56亿元; 491.05、 404.36亿元; 581.55、 465.65亿元, 土地类型的改变使得植被、 土壤固碳分别增长12.72%、 30.39%。从空间分布上看, 东部植被、 土壤固碳量明显高于西部, 林地固碳能力最高, 单位面积固碳量为10.19 t·hm^-2。草地是研究区分布最广的植被, 且其对该地区植被、 土壤固碳贡献比为51.13%、 49.34%。  相似文献   

外源一氧化氮供体对盐胁迫下多裂骆驼蓬幼苗光合作用和叶黄素循环的影响   总被引：2，自引：1，他引：1  

刘建新  王鑫  李博萍 《中国沙漠》2011,31(1):137-141

一氧化氮(NO)是植物体内新发现的一种活性分子。为了探讨外源NO对盐胁迫下荒漠植物光合生理响应的调节作用,以多裂骆驼蓬为试验材料,研究叶面喷施NO供体硝普钠(SNP)预处理对根施NaCl胁迫下叶片光合色素含量、气体交换参数、叶绿体Hill反应活力和ATPase活性、叶绿素荧光参数及叶黄素循环的影响。结果表明:①0.15 mmol·L-1SNP可显著缓解300 mmol·L-1NaCl胁迫下叶绿素a、b和类胡萝卜素含量及净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和气孔限制值(Ls)的下降和细胞间隙CO2浓度(Ci)的升高;②SNP处理减小了NaCl胁迫诱导的叶绿体Hill反应活力和Ca2+-ATPase、Mg2+-ATPase活性的下降幅度;③NaCl胁迫下叶绿体最大荧光(Fm)、PSⅡ潜在光化学效率(Fv/F0)、最大光化学效率(Fv/Fm)、实际光化学效率(ΦPSⅡ)和光化学猝灭系数(qP)显著降低,天线热耗散(D)略微下降,初始荧光(F0)和非光化学猝灭系数(NPQ)明显提高。SNP处理使NaCl胁迫下的F0显著降低,Fm、Fv/F0、Fv/Fm、ΦPSⅡ、qP、NPQ和D明显提高;④NaCl胁迫引起叶黄素循环库(V+A+Z)显著降低和脱环氧化状态(A+Z)/(V+A+Z)明显提高,SNP处理使NaCl胁迫下的V+A+Z明显提高,(A+Z)/(V+A+Z)显著下降。由此表明,NO能够缓解盐胁迫下非气孔因素引起的光合速率的下降及光抑制对光合系统的破坏作用,而非光化学效率的提高和天线热耗散的增强可能是NO 保护光合系统并提高光合速率的重要机制之一。  相似文献