低温对厚皮甜瓜幼苗光合特性的影响   总被引：2，自引：0，他引：2  

陈年来  王兴虎  安黎哲  王刚 《冰川冻土》2009,31(5):986-991

在人工控制条件下研究了低温对厚皮甜瓜幼苗光合特性的影响.结果表明:低温(昼15℃/夜5℃)胁迫导致甜瓜幼苗的光合色素含量和叶片光能捕捉下降,可利用光强范围变窄,对CO2的利用效率降低,光合作用的瞬时水分利用效率显著降低.在亚适宜温度(昼20℃/夜10℃)下,制约甜瓜光合作用的主导因素为气孔限制,在胁迫低温下则以非气孔因素为主.气孔限制在降低植物碳同化速率的同时,也提高了水分利用效率.低温条件下,伊丽莎白较黄河蜜具有更高的光合色素含量、更大的光能和CO2利用效率、更强的弱光和低浓度CO2利用能力.甜瓜温室型品种伊丽莎白对低温的适应性优于露地品种黄河蜜.  相似文献   

柑橘植株冠层氮素和光合色素含量近地遥感估测   总被引：1，自引：0，他引：1  

刘雪峰  吕强  何绍兰  易时来  谢让金  郑永强  胡德玉  汪志涛  邓烈 《遥感学报》2015,19(6):1007-1018

柑橘植株营养状况的遥感监测是实现果树轻简高效管理和优质丰产的重要手段,但迄今有关基于低空遥感信息的果树营养诊断研究鲜见报道。本文采用具有490 nm、550 nm、570 nm、671 nm、680 nm、700 nm、720 nm、800 nm、840 nm、900 nm、950 nm等11个波段光谱的八旋翼飞行器(UAV)载多光谱遥感系统,获取距地面100 m高度的哈姆林甜橙植株春季冠层近地遥感信息,对比分析基于多元散射校正(MSC)和标准正态变量(SNV)两种预处理光谱和原始光谱(OS)的偏最小二乘(PLS)、多元线性回归(MLR)、主成分回归(PCR)及最小二乘支持向量机(LS-SVM)等4种模型对冠层叶片氮素、叶绿素a、叶绿素b和类胡萝卜素含量预测精度的影响。结果显示,距地面100 m高度的多光谱信息,通过SNV光谱预处理和MLR建模对冠层叶片氮素、叶绿素a和叶绿素b含量的预测效果均较好,预测集相关系数(Rp)值分别达0.8036、0.8065和0.8107,预测均方根误差(RMSEP)值分别为0.1363、0.0427和0.0243;而在SNV光谱预处理基础上的LS-SVM建模对冠层类胡萝卜素含量预测效果更优,Rp值达到了0.8535,RMSEP值为0.0117。表明利用机载多光谱图像信息可实现对柑橘植株冠层全氮及叶绿素a、叶绿素b和类胡萝卜素含量的较好估算,为大规模柑橘园植株冠层营养状况的精准和高效监测提供了一条新途径。  相似文献   

南极长城站附近海区冰藻色素的初步分析          下载免费PDF全文

李宝华  黄凤鹏  张坤诚 《极地研究》1992,4(4):18-23

本文报道了 1 988年 6 - 1 2月 (结冰期 )南极长城站附近海区冰藻色素的分离、鉴定结果。探讨了该海区冰藻色素的种类组成 ,季节变化以及冰藻色素在海洋生态系中的作用。结果表明 ,该海区冰藻已分离出色素 1 5种 ,可鉴定的有 1 3种 ,分别为 :胡萝卜素 ,脱镁叶绿素 a,叶绿素 a、b、c,叶黄素 ,岩藻黄质 ,脱植基叶绿酸 a,紫黄质 ,脱镁叶绿素 c,叶绿酸 a,叶绿素 c的衍生物 ,di-adinoxanthin,二种色素未能鉴定。该海域冰藻色素具明显的季节变化。  相似文献   

A late-Glacial diatom and pigment history of Little Lake,New Brunswick with particular reference to the younger Dryas climatic oscillation     

David J. Rawlence  A. Senior 《Journal of Paleolimnology》1988,1(3):163-177

Diatom and pigment data are presented from a 6.39 m core from Little Lake, New Brunswick. From its inception to ca. 11.5k y.B.P., the lake was dominated by benthic alkaliphilic diatoms, predominantly Fragilaria spp, which are believed to have grown in the moat of a lake with extended periods of ice cover. Ice free summers apparently prevailed for up to 500 years (ca. 11.5–11k y.B.P.), during which time planktonic species — Cyclotella bodanica Eulenst. and C. stelligera Cl. & Grun. appeared for the first time. From ca. 11.–10k y.B.P. the lake was dominated by Fragilaria pinnata Ehr.v. pinnata, F. construens v. venter (Ehr.) Grun. and F. construens (Ehr.) Grun. The reappearance of these species, coincident with distinct changes in sediments, organic matter, pollen types and influx rates, is believed to represent the influence of the younger Dryas climatic cooling. Little Lake appears to have reverted to a period of only partial summer melting. The ca. 10k y.B.P. warming is marked by a Navicula/Cymbella/Cyclotella community, representing growth of both littoral and planktonic communities. Navicula was subsequently replaced by Eunotia and Tabellaria, and finally by a Pinnularia/Stauroneis/Eunotia community, in which Fragilaria pinnata v. pinnata and F. construens v. venter increase again. These two recent phases represent increasing growth of a littoral community, and some increase in littoral alkaliphilous elements. Trends in organic matter and pigment values are consistent with a gradual increase in biomass, particularly from ca. 10k y.B.P. Diatom growth is indicative of increasing littoral and benthic growth with time, but there is no indication that Little Lake was ever eutrophic.  相似文献   

A palaeoenvironmental study of Fairfax Lake,a small lake situated in the rocky mountain foothills of west-central Alberta     

Michael Hickman  Charles E. Schweger 《Journal of Paleolimnology》1991,6(1):1-15

Fairfax Lake is a small, oligotrophic to mesotrophic headwater lake situated in the Foothills of the Rocky Mountains of west-central Alberta (Latitude 52° 58 N; Longitude 116° 34 W). Through acquisition of a sediment core, and analyses of the diatoms, chrysophyte stomatocysts, pollen and sedimentary pigments, including myxoxanthophyll and oscillaxanthin, a palaeoenvironmental history of the lake has been determined. The sedimentary record spans ca. 13 200 years. An open tree-less vegetation existed in the region ca. 13 200–ca. 11 600 years BP. Maximum oscillaxanthin and myxoxanthophyll concentrations, hence the largest blue-green algal populations, occurred during the same interval. With increasing temperature pioneering parkland vegetation appeared ca. 11 600 years BP but was replaced ca. 10 100 years BP by spruce forest. Pine appeared ca. 7800 years BP and this marked the development of the present day montane boreal forest. Diatoms were not found until ca. 11 255 years BP. Benthic taxa dominated but by ca. 10 100 years BP planktonic taxa had become more prominent. Lake levels are interpreted as having risen, and the lake water was probably more transparent. Maximum chlorophyll and total carotenoid concentrations occur ca. 11 255 to ca. 7000 years BP corresponding to the warm early to mid-Holocene period. Lake nutrient levels appear to have been higher prior to ca. 7000 years BP, and the lake has changed from being eutrophic during the early Holocene to its present status as an oligotrophic to mesotrophic lake. Subtle hydrological changes have also occurred in the catchment as water levels do not appear to have remained constant.  相似文献   

Analysis of fossil pigments from algae and bacteria in meromictic Lake Fidler, Tasmania, and its application to lake management   总被引：6，自引：0，他引：6  

Dominic A. Hodgson  Simon W. Wright  Peter A. Tyler  Noel Davies 《Journal of Paleolimnology》1998,19(1):1-22

Lake Fidler is an ectogenic meromictic lake with a monimolimnion maintained by periodic incursions of brackish water from the lower Gordon River estuary. A dam across the middle reaches of the Gordon River has restricted these incursions of brackish water and meromictic stability has rapidly declined. A palaeolimnological study was carried in order to assess the historical development of meromixis and the impact of the dam on the microbiological communities in the lake. Fossil pigments in a 17 m sediment core were analysed using reverse phase high performance liquid chromatography (rp-HPLC) and mass spectrometry (MS). In addition, taphonomic studies of pigment production, deposition and degradation in the water column and surface sediments were used to identify planktonic and benthic pigment degradation processes and constrain the stratigraphic interpretation. Results comparing the pigment composition of pelagic sediment traps and littoral surface sediments indicated that the core from the centre of the lake would permit a historical reconstruction of planktonic bacterial and algal communities. Marked increases in prokaryotic pigments ca 3500 yr B.P. suggested the possible colonisation of a chemocline by phototrophic bacteria. Further changes in chlorophyll: carotenoid ratios and changes in relative abundances of both chlorophyll a and bacteriochlorophyll c derivatives also indicated that a change in the depositional environment had occurred; possibly due to altered stratification or anoxia. From this we infer the onset of either intermittent or permanent meromixis. Further increases in prokaryotic pigment abundance suggested that the present state of permanent meromixis was firmly established by 2070 ±50 ¹⁴C yr B.P., and diatom analysis confirmed the development of a stable mixolimnion. High resolution studies of the top 10 cm of sediments measured pigments in mean concentrations of 15.1 ng g^-1 with a mean S.D. of only 2.78 indicating little change in pigment abundance since the construction of the dam. Thus, Lake Fidler still retains most of the features of meromixis. However, evidence from nearby Lake Morrison and Sulphide Pool has shown that any further declines in meromictic stability will cause a rapid reversion to holomixis. Palaeolimnological evidence from the early stages of meromictic development of Lake Fidler suggests that such reversion to holomixis may not permanently eliminate all the microbiological communities, and that, given time, they may return and prosper with re-establishment of a suitable chemocline. These studies will guide recommendations for a management strategy to prevent the further decay of meromixis in the Gordon River lakes.  相似文献   

Distribution and vertical dynamics of planktonic communities at Sofala Bank, Mozambique     

M.C. Leal  C. S  S. Nordez  V. Brotas  J. Paula 《Estuarine, Coastal and Shelf Science》2009,84(4):605-616

Coastal ecosystem processes are largely influenced by the interaction of different factors operating at various temporal and spatial scales, specifically those responsible for primary production patterns that modulate zooplankton and subsequent trophic levels. Hydrological processes, such as tidal cycles and coastal currents, nutrients availability, phytoplankton groups (studied through algal pigment signatures analysed by HPLC), and zooplankton abundance and distribution were investigated at the Sofala Bank (Mozambique), with special emphasis on their horizontal distribution and vertical dynamics (48 h). Horizontal distribution has shown inshore–offshore gradients in all analysed parameters, as well as inshore waters intrusion probably related to Zambezi River delta runoff. Tidal currents were responsible for major hydrological vertical variations and for horizontal and vertical advection of phytoplankton biomass in the surface and deepest layers, respectively. Nutrient concentrations were typical from oligotrophic regions, and nutrient ratios were strongly influenced by depleted nitrate + nitrite concentrations, indicating low estuarine discharges typical from the dry season. The very low N:P ratio obtained suggests strong nitrogen limitation to phytoplankton communities, supporting the low phytoplankton abundance observed. Both phytoplankton pigments and zooplankton were found mainly near the bottom (40 m depth), despite the latter displayed vertical migrations triggered by light variations. Phytoplankton community was dominated by microflagellates, specifically prymnesiophyceans, and behaved as a whole, except Cyanobacteria that displayed vertical distribution movements different from other phytoplankton groups, being mainly concentrated at mid-water column depths (10–20 m). This investigation enhances physico-chemical phenomena and their importance determining the planktonic communities vertical dynamics at Sofala Bank, a tropical coastal ecosystem of the Western Indian Ocean where planktonic dynamics are still poorly described and understood.  相似文献   

Characteristics of phytoplankton community structure during and after a bloom of the dinoflagellate Scrippsiella trochoidea by HPLC pigment analysis     

Chun-kwan Wong  Chong-kim Wong 《中国海洋大学学报(英文版)》2009,8(2):141-149

A bloom of the dinoflagellate Scrippsiella trochoidea was detected for the first time in inner Tolo Harbor, Hong Kong in 2 000. Water samples were collected at eight stations along a transect passing through a red tide patch for microscopic analysis of phytoplankton composition and high-performance liquid chromatography (HPLC) analysis of phytoplankton pigments. During the bloom, the density of dinoflagellates was 1.1×10⁶ cells L⁻¹ within the patch and 8.6×10⁵ cells L⁻¹ outside the patch where the phytoplankton community was dominated by diatoms. After the bloom the S. trochoidea began to decrease in density and was replaced by diatoms as the dominating bloom-causing organisms at all stations, and the density of dinoflagellates at most stations was less than 1.0 × 10⁶ cells L⁻¹. The status of S. trochoidea as the causative species of the bloom was indicated by the presence of peridinin, the marker pigment for dinoflagellates. The shift from dinoflagellates to diatoms was marked by the decline of peridinin and the prevalence of fucoxanthin. Phytoplankton pigment markers also revealed the presence of other minor phytoplankton assemblages such as cryptomonads and blue-green algal.  相似文献   

Estuarine phytoplankton dynamics and shift of limiting factors: A study in the Changjiang (Yangtze River) Estuary and adjacent area   总被引：5，自引：0，他引：5  

Zhuo-Yi Zhu  Wai-Man Ng  Su-Mei Liu  Jing Zhang  Jay-Chung Chen  Ying Wu 《Estuarine, Coastal and Shelf Science》2009,84(3):393

Environmental factors in estuaries are highly variable in terms of both spatial and temporal dimensions and hence phytoplankton biomass, as well as community structure, is dynamic. Two cruises were carried out in the Changjiang (Yangtze River) Estuary and adjacent area in spring and summer. The result of CHEMTAX calculation suggests that in spring diatoms and chlorophytes contribute equally to phytoplankton biomass, while phytoplankton community structure is mainly composed of diatoms in summer. We encountered blooms in summer with chlorophyll a (CHLa) over 10 μg l⁻¹ off the Changjiang Estuary and they were mainly caused by diatoms (>90%). Based on the HPLC analysis of samples collected, phytoplankton pigments mainly concentrated beyond the front between 122.5°E and 123°E where nutrients and turbidity were best balanced. Euphotic depth (Z_eu, calculated from Secchi disk depth) to surface mixed layer depth (Z_mix) ratio (i.e. Z_eu/Z_mix) were comparable in spring (average value 1.2) and the ratio increased to 5.2 in summer. Variation of the ratio indicates an apparent shift of light and physical conditions from spring to summer. Correspondingly, CHLa was positively related to Z_eu/Z_mix ratio (r² = 0.83) in spring, indicating the light limitation over the whole investigation area. On the other hand, the relationship of CHLa and Z_eu/Z_mix ratio became unclear when Z_eu/Z_mix ratio >3 in summer. This is probably due to the combination of both light limitation before the front and nutrient limitation beyond the front. In addition, evidence was found that light condition can impact the diagnostic pigments in the Changjiang Estuary.  相似文献   

THE BIOGEOCHEMISTRY OF PHOTOSYNTHETIC PIGMENTS IN THE JIULONG RIVER ESTUARY AND WESTERN XIAMEN BAY   总被引：2，自引：0，他引：2  

徐立  洪华生  王海黎  陈伟琪 《中国海洋湖沼学报》2001,19(2):164-171

ＩＮＴＲＯＤＵＣＴＩＯＮＫｎｏｗｌｅｄｇｅｏｆｔｈｅｄｉｓｔｒｉｂｕｔｉｏｎａｎｄｃｏｍｐｏｓｉｔｉｏｎｏｆｔｈｅｃｈｌｏｒｏｐｈｙｌｌａｎｄｃａｒｏｔｅｎｏｉｄｐｉｇｍｅｎｔｓｉｎｃｏａｓｔａｌｍａｒｉｎｅｗａｔｅｒｓｐｒｏｖｉｄｅｓｉｎｆｏｒｍａｔｉｏｎｏｎｔｈｅｐｈｙｔｏｐｌａｎｋｔｏｎｂｉｏｍａｓｓａｎｄａｌｓｏｏｎｉｔｓｃｈｅｍｏｔａｘｏｎ ｏｍｙ ,ｔｈｅｃｏｎｔｒｉｂｕｔｉｏｎｏｆｒｉｖｅｒｉｎｅｉｎｐｕｔｓ,ａｎｄｔｈｅｅａｒｌｙｄｅｇｒａｄａｔｉｏｎｒｏｕｔｅｓｏｃｃｕｒｒｉｎｇｉ…  相似文献