不同温度条件下无机碳浓度增高对石莼光合作用的影响   总被引：3，自引：0，他引：3  

邹定辉  高坤山 《海洋科学》2002,26(3):49-52

为了探讨在不同光温条件下石莼（Ulva lactuca)光合作用对无机碳的需求，于1999年6-7月，在提高海水无机碳浓度（8.8mol/L)的条件下，对石莼光合作用的光温反应特性进行了研究，结果表明，无机碳浓度增高对石莼光合作用的影响对温度有依赖性。增加无机碳浓度，在30℃较高温度下，显著地提高了光饱和光合速率，而在10℃较低温度下，其影响不明显，在温度20-30℃范围内时，无机碳浓度增高使光合速率的温度系数增加，而在温度10-20℃范围内时则没有影响，较高的光温度条件使石莼光合作用对无机碳的需求增加。  相似文献   

Ecophysiological Studies of the Adriatic Seaweed, Fucus virsoides     

B. P. Kremer  I. M. Munda 《Marine Ecology》1982,3(1):75-93

Abstract. The Adriatic brown macroalga Fucus virsoides (DON.) J. Ac (Fucales, Phaeophyceae) was investigated with particular respect to basic physiological features such as photosynthesis, dark carbon fixation, and respiration. Values obtained are expressed in various reference systems. Chemical composition of the fronds and physiological activity (photosynthesis/dark fixation along with the respective carboxytating enzymes (ribulose-1,5-bisphophate carboxylase and phosphoenol-pyruvate carboxykinase) show longitudinal profiles. Temperature characteristics of photosynthesis in long-term adapted specimens indicate reduced productivity at temperatures exceeding 20 °C. Photosynthesis during atmospheric exposure is markedly increased under moderate desiccation. Photosynthetic rates steadily decline under reduced salinity of the incubation medium, while respiration is stimulated. Net primary productivity of a F. virsoides stand at 15 °C ambient average temperature, tidal exposure for maximally 2–3 hours and light-dark regime = 12: 12 is calculated as 4.8-5.4 g C m^-2d-1. Culture experiments with polluted incubation media provide evidence that excessive nutrients including nitrate and phosphate as well as high concentrations of heavy metals (Zn, Co, Mn) cause severe growth-rate reduction which may account for the steady decrease of F. virsoides in its natural habitat. The results are discussed with emphasis on the autecology of F. virsoides and its relationships to Atlantic representatives of the genus.  相似文献   

The Influence of Hilly Terrain on Canopy-Atmosphere Carbon Dioxide Exchange   总被引：1，自引：1，他引：1  

G. G. Katul  J. J. Finnigan  D. Poggi  R. Leuning  S. E. Belcher 《Boundary-Layer Meteorology》2006,118(1):189-216

Topography influences many aspects of forest-atmosphere carbon exchange; yet only a small number of studies have considered the role of topography on the structure of turbulence within and above vegetation and its effect on canopy photosynthesis and the measurement of net ecosystem exchange of CO₂ (N_ee) using flux towers. Here, we focus on the interplay between radiative transfer, flow dynamics for neutral stratification, and ecophysiological controls on CO₂ sources and sinks within a canopy on a gentle cosine hill. We examine how topography alters the forest-atmosphere CO₂ exchange rate when compared to uniform flat terrain using a newly developed first-order closure model that explicitly accounts for the flow dynamics, radiative transfer, and nonlinear eco physiological processes within a plant canopy. We show that variation in radiation and airflow due to topography causes only a minor departure in horizontally averaged and vertically integrated photosynthesis from their flat terrain values. However, topography perturbs the airflow and concentration fields in and above plant canopies, leading to significant horizontal and vertical advection of CO₂. Advection terms in the conservation equation may be neglected in flow over homogeneous, flat terrain, and then N_ee = F_c, the vertical turbulent flux of CO₂. Model results suggest that vertical and horizontal advection terms are generally of opposite sign and of the same order as the biological sources and sinks. We show that, close to the hilltop, F_c departs by a factor of three compared to its flat terrain counterpart and that the horizontally averaged F_c-at canopy top differs by more than 20% compared to the flat-terrain case.  相似文献   

水生植物对岩溶水化学日变化的影响——以桂林岩溶水文地质试验场为例   总被引：8，自引：3，他引：5  

吕保樱  刘再华  廖长君  孙海龙 《中国岩溶》2006,25(4):335-340

以桂林岩溶水文地质试验场为研究点,以研究水生植物对岩溶水化学日变化的影响为目的,着重研究水葫芦和水藻对岩溶水的pH、电导率、溶解氧含量、方解石饱和指数以及CO2 分压日变化的影响。试验结果表明: 在不同水生植物生长的岩溶水中,水化学的日动态变化规律是不同的。在水藻生长的水池出水口处,水的pH、电导、溶解氧含量、饱和指数以及CO2 分压所受的影响主要以水生植物的光合作用为主;而在有水葫芦生长的岩溶水中,水生植物的光合作用影响降低,而温度和根呼吸作用的影响增强。在以桂林岩溶水文地质试验场S31号泉水池出水口堰板处和堰板下游约3m 处为监测点试验时,试验结果表明其水生植物的影响占70%以上,强于温度作用的影响。   相似文献   

Modeling ocean primary production: Sensitivity to spectral resolution of attenuation and absorption of light     

Helen Kettle  Chris J. Merchant 《Progress in Oceanography》2008,78(2):135-146

Modeling the vertical penetration of photosynthetically active radiation (PAR) through the ocean, and its utilization by phytoplankton, is fundamental to simulating marine primary production. The variation of attenuation and absorption of light with wavelength suggests that photosynthesis should be modeled at high spectral resolution, but this is computationally expensive. To model primary production in global 3d models, a balance between computer time and accuracy is necessary. We investigate the effects of varying the spectral resolution of the underwater light field and the photosynthetic efficiency of phytoplankton (α^*), on primary production using a 1d coupled ecosystem ocean turbulence model. The model is applied at three sites in the Atlantic Ocean (CIS (60°N), PAP (50°N) and ESTOC (30°N)) to include the effect of different meteorological forcing and parameter sets. We also investigate three different methods for modeling α^* – as a fixed constant, varying with both wavelength and chlorophyll concentration [Bricaud, A., Morel, A., Babin, M., Allali, K., Claustre, H., 1998. Variations of light absorption by suspended particles with chlorophyll a concentration in oceanic (case 1) waters. Analysis and implications for bio-optical models. J. Geophys. Res. 103, 31033–31044], and using a non-spectral parameterization [Anderson, T.R., 1993. A spectrally averaged model of light penetration and photosynthesis. Limnol. Oceanogr. 38, 1403–1419]. After selecting the appropriate ecosystem parameters for each of the three sites we vary the spectral resolution of light and α^* from 1 to 61 wavebands and study the results in conjunction with the three different α^*estimation methods. The results show modeled estimates of ocean primary productivity are highly sensitive to the degree of spectral resolution and α^*. For accurate simulations of primary production and chlorophyll distribution we recommend a spectral resolution of at least six wavebands if α^* is a function of wavelength and chlorophyll, and three wavebands if α^* is a fixed value.  相似文献   

温度、光照强度和pH对雨生红球藻光合作用和生长速率的影响   总被引：19，自引：0，他引：19       下载免费PDF全文

张宝玉  李夜光  李中奎  耿亚红  胡鸿钧 《海洋与湖沼》2003,34(5):558-565

采用测定净光合放氧速率的方法研究了温度、光照强度和pH对 4株雨生红球藻光合作用和生长繁殖速率的影响。结果表明 ,温度、光照强度和pH对雨生红球藻的光合作用和生长速率的影响十分显著 ;4株雨生红球藻光合作用的最适温度、光饱和点和pH分别为 :Haematococcuspluvialis 2 6 :1 5℃ ,2 5 0 μmol/(m2 ·s)和pH7 0 ;Haematococcuspluvialis 3 0 :2 0℃ ,2 0 0 μmol/(m2 ·s)和pH8 0 ;Haematococcuspluvialis 3 4 :1 5℃ ,2 0 0 μmol/(m2 ·s)和pH7 0 ;Haematococ cuspluvialisWZ :1 0℃ ,1 40 μmol/(m2 ·s)和pH6 0。雨生红球藻细胞数量的增加与光照时间成正比。初步认为H pluvialis3 0、H pluvialis2 6和H pluvialisWZ是 3个有潜力适合于大规模生产的藻种。  相似文献   

4种单胞藻同化速率与温度关系的实验研究   总被引：4，自引：0，他引：4  

王宪  李文权 《台湾海峡》1990,9(3):287-290

本文采用~(14)C示踪法,实验研究了温度对小球藻、牟氏角毛藻、聚生角毛藻和钙质角毛藻同化速率的影响,发现这4种藻类的同化速率随温度呈非线性函数变化,并从理论上阐述了藻类生长过程中对温度的要求和适应,以及这4种藻类光合过程的平均活化能。  相似文献   

陆面模式的植物叶光合生理的数值模拟试验及分析     

张佳华  姚凤梅 《气象科学》2007,27(4):419-424

根据C3、C4植物生态生理过程中植物叶水平的光合同化机制过程和植物叶片尺度的光合作用限制函数方程。采用单叶光合作用模式进行C3、C4植物光合模拟试验,模拟不同环境影响因子对C3、C4植物光合作用的影响。结果表明,植物叶尺度光合作用模型能较好地模拟不同环境影响因子下的C3、C4植物光合作用状况。本文依据C3、C4植物光合生理特性进一步分析植物光合作用的三个限制函数方程在C3、C4植物光合的不同作用,揭示吸收光合有效辐射(PAR)、叶内温度(Tc)和CO2浓度(Ci)的敏感性。结果可用于植被—大气相互作用的能量和碳同化过程的物质交换研究。  相似文献   

Spartina densiflora demonstrates high tolerance to phenanthrene in soil and reduces it concentration     

Redondo-Gómez S  Andrades-Moreno L  Parra R  Valera-Burgos J  Real M  Mateos-Naranjo E  Cox L  Cornejo J 《Marine pollution bulletin》2011,62(8):1800-1808

The present study was conducted to investigate the tolerance of Spartina densiflora to phenanthrene, and to test its ability in phenanthrene dissipation. A glasshouse experiment was designed to investigate the effect of phenanthrene from 0 to 1000 mg kg⁻¹ on growth and photosynthetic apparatus of S. densiflora by measuring chlorophyll fluorescence parameters, gas exchange and photosynthetic pigments. We also performed chemical analysis of plant samples, and determined the concentration of phenanthrene remaining in soil. S. densiflora survived to concentrations as high as 1000 mg kg⁻¹ phenanthrene in soil; in fact, there was no significant difference in RGR among the treatments after 30 days. Otherwise, phenanthrene affected photosynthetic apparatus at 100 and 1000 mg kg⁻¹; thus, the lower Φ_PSII could be explained by the declined photosynthetic pigment concentrations. Soil extraction indicated a more marked rate of phenanthrene disappearance in the soil in the presence of S. densiflora.  相似文献   

Biological control reduces growth, and alters water relations of the saltcedar tree (Tamarix spp.) in western Nevada, USA     

R.R. Pattison  C.M. D’Antonio  T.L. Dudley 《Journal of Arid Environments》2011,75(4):346-352

We monitored the impacts of a biological control agent, the saltcedar leaf beetle (Diorhabda carinulata), on the saltcedar tree (Tamarix spp.) at two sites (Humboldt and Walker rivers) in Nevada, USA. At the Humboldt site trees that had experienced three to four defoliation events had more negative water potentials and lower foliar Δ¹³C than trees farther from the release site that had experienced only one defoliation event. We established paired trees (exposed to D. carinulata and sprayed with insecticide) at both sites and monitored impacts. Beetles reduced stem growth during the first year of defoliation at both sites but not in the second year at the Humboldt site. Defoliation did not affect midday water potentials, or leaf gas exchange during the first two years of defoliation of paired trees at either site. Furthermore there was no difference in foliar Δ¹³C in either year at the Humboldt site but defoliation during the first year lead to higher foliar Δ¹³C at the Walker site. These results suggest that initial defoliation by D. carinulata reduces growth but not water relations of saltcedar. However, repeated defoliation, potentially acting through reduced root growth, leads to an overall reduction in the water status of this invader.  相似文献