Isolation of Protoplasts from Undaria pinnatifida by Alginate Lyase Digestion

1　Introduction　Protoplastsserveasabasicandversatiletoolforge neticengineeringandbiochemicalresearchforseveralreasons :theymayregeneratetheirwallsandprovideamodelsystemforstudyingwallbiogenesis ,theirlysisprovidesagentlemeansofpreparingsubcellularor ganelles ,andthemembraneexpositionallowsgeneticmanipulationsinvolvingfusionoruptakeofnucleicacidstobepossible .Theseadvantagesarelessachiev ablewhenusingintactcells (Liciaetal.,1999) .Incomparisonwithlandplantsandunicellularalgae ,on lylimitedrepo…     

Seasonal and annual variation of CO2 flux above a broad-leaved Korean pine mixed forest

Long-term measurement of carbon metabolism of old-growth forests is critical to predict their behaviors and to reduce the uncertainties of carbon accounting under changing climate. Eddy covariance technology was applied to investigate the long-term carbon exchange over a 200 year-old Chinese broad-leaved Korean pine mixed forest in the Changbai Mountains (128°28′E and 42°24′N, Jilin Province, P. R. China) since August 2002. On the data obtained with open-path eddy covariance system and CO₂ profile measurement system from Jan. 2003 to Dec. 2004, this paper reports (i) annual and seasonal variation of F _NEE, F _GPP and R _E; (ii) regulation of environmental factors on phase and amplitude of ecosystem CO₂ uptake and release Corrections due to storage and friction velocity were applied to the eddy carbon flux.

L_AI and soil temperature determined the seasonal and annual dynamics of F_GPP and R_E separately. V_PD and air temperature regulated ecosystem photosynthesis at finer scales in growing seasons. Water condition at the root zone exerted a significant influence on ecosystem maintenance carbon metabolism of this forest in winter.

The forest was a net sink of atmospheric CO₂ and sequestered −449 g C·m⁻² during the study period; −278 and −171 gC·m⁻² for 2003 and 2004 respectively. F _GPP and F _RE over 2003 and 2004 were −1332, −1294 g C·m⁻². and 1054, 1124 g C·m⁻² respectively. This study shows that old-growth forest can be a strong net carbon sink of atmospheric CO₂.

There was significant seasonal and annual variation in carbon metabolism. In winter, there was weak photosynthesis while the ecosystem emitted CO₂. Carbon exchanges were active in spring and fall but contributed little to carbon sequestration on an annual scale. The summer is the most significant season as far as ecosystem carbon balance is concerned. The 90 days of summer contributed 66.9, 68.9% of F _GPP, and 60.4, 62.1% of R _E of the entire year.

     

An Example of Island-Arc Petrogenesis: Geochemistry and Petrology of the Southern Luzon Arc, Philippines

Volcanism throughout the Luzon arc is associated with eastwardsubduction of the South China Sea floor along the Manila Trench.The southern section of the arc, the focus of this study, extendsfrom the Lingayen-Dingalan fault to the small islands just southof Luzon. Two segments appear to exist along this section ofthe arc the northern Bataan and southern Mindoro segments whichare separated by the Macolod Corridor. The volcanic rocks have typical arc phenocryst mineralogies:olivine, clinopyroxene, plagioclase, and titanomagnetite inthe most mafic rocks and clinopyroxene, plagioclase, orthopyroxene,titanomagnetite, ? amphibole in the more felsic samples. Complexzoning, sieve textures, and decoupling of incompatible traceelements suggest that processes such as assimilation have takenplace. The rocks from the study area range from basalts to rhyolitesand show typical calc-alkaline features. The rocks of the MacolodCorridor and Mindoro segment are particularly enriched in largeion lithophile elements (LILE), light rare earth elements (LREE),and radiogenic Sr compared with the Bataan segment. The datafall within the mantle array on Sr-Nd isotopic diagrams andgrade toward higher Sr and lower Nd isotopic values from northto south. A likely source for the volcanics of this study is either amid-ocean ridge basalt (MORB)-type mantle that undergoes higherdegrees of partial melting than regions involved in MORB generationor a previously depleted source. We suggest that the high fieldstrength element (HFSE) anomalies have been derived throughdifferential element partitioning during fluid transport fromthe subducted lithosphere to the mantle wedge. Continental crustal material seems to play a significant roleparticularly in the Macolod Corridor and the Mindoro segment,based on the high LILE, La/Sm ratios, radiogenic Sr isotopes,and ¹⁸O values. The Macolod Corridor and the Mindoro segmenthave undergone source contamination by crustal material fromthe North Palawan-Mindoro crustal block either during the collisionof this block with the Manila Trench or by subduction of sedimentsrich in this crustal material. A similar component has alsobeen detected in the Bataan segment but in minor amounts. Thetrace element and isotopic differences between the northernand southern sections of the arc are interpreted in terms ofvariable composition (i. e., variable amounts of a crustal componentintroduced from the Palawan-Mindoro crustal terrain) of themetasomatic fluids released into the source.     

Major features of warm and cold eddies south of the Nansei Islands

As regards the eddies occurring in the origination region of the Kuroshio (west of 130° E), the earliest informations were reported by R. Shigematsu (1932) and K. Koenuma (1936) respectively. From the data observed in the twenties, they pointed out that there was a warm eddy located to the right side of the Kuroshio in the Luzon Strait. Using the data obtained from the fourties through the sixties, Nitani further convinced the existence of the warm eddy. During the latest two decades, observations of the area south of the Nansei Islands on board of R/V Chofu Maru (1965, '66, '67) and Hakuho Maru (1974, '75) also revealed the existence of warm and cold eddies, but few works on "eddies" are reported, so far as we know.     

Decoupling of stalagmite-derived Asian summer monsoon records from North Atlantic temperature change during marine oxygen isotope stage 5d

The Asian monsoon is an important component of the global climate system. Seasonal variations in wind, rainfall, and temperature associated with the Asian monsoon systems affect a vast expanse of tropical and subtropical Asia. Speleothem-derived summer monsoon variation in East Asia was previously found to be closely associated with millennial-scale change in temperature in the North Atlantic region between 75 and 10 ka. New evidence recovered from East Asia, however, suggests that the teleconnection between summer monsoon in East Asia and temperature change in the North Atlantic region may have significantly reduced during 120 to ~ 110 ka, a period directly after the full last interglaciation and corresponding roughly to marine oxygen isotope stage 5d. This reduction may be due to the low ice volume in the North Hemisphere at that time, which makes the millennial-scale change in temperature in the North Atlantic region less effective in influencing the Asian summer monsoon. This is important for investigating the mechanisms controlling the Asian summer monsoon and the paleoclimatic teleconnection between East Asia and the North Atlantic region, and for predicting monsoon-associated precipitation in East Asia under a global-warming trend.     

Modeling of water–rock interactions in an aquitard of sandy clay in the coastal area near Beihai,China

Unconsolidated sand, gravel and clay deposits near Beihai and in the Leizhou Peninsula in southern China form an unconfined aquifer, aquitard and a confined aquifer. Water and soil samples were collected from the two aquifers in the coastal Beihai area for the determination of chemical compositions, minerals and soluble ions. Hydrogeochemical modeling of three flow paths through the aquitard are carried out using PHREEQC to determine water–rock interactions along the flow paths. The results indicate that the dissolution of anorthite, fluorite, halite, rhodochrosite and CO₂, and precipitation of potash feldspar and kaolinite may be occurring when groundwater leaks through the aquitard from the unconfined aquifer to the confined aquifer. Cation exchanges between Na and Ca can also happen along the flow paths.     

分光光度法测定海洋河弧菌510脂多糖

本文研究了直接测定海洋河弧菌 (vibrio fluvailis) 5 10脂多糖的分光光度法。利用 1,9-二甲基亚甲蓝 (DMB) ,在适当条件下同脂多糖发生染色反应 ,在 5 5 0 nm波长下 ,反应体系的吸光值同脂多糖含量呈线性相关。相关系数为 0 .9993,最低检出限为 10 μg/m L,相对标准偏差为 1.6 2 ,平均回收率为 (10 5± 2 .18) %。     

Diel Patterns in Chlorophyll <Emphasis Type="Italic">a</Emphasis> Specific Absorption Coefficient and Absorption Efficiency Factor of Picoplankton

Diel patterns in the chlorophyll a specific absorption coefficient of surface picoplankton, a*_pico (γ) (m²·[mg chlorophyll a]⁻¹), were studied at 7 stations under daily cycle of in situ light condition in the western subarctic Pacific and Japan Sea. All the data were normalized by dividing the anomaly with daily averaged a*_pico (γ). Opposite diel patterns were observed for the normalized a*_pico (443) and a*_pico (675) with maximum toward dawn or dusk and minimum toward midday at 4 stations under low-irradiance (LI) conditions and vice versa at 3 stations under high-irradiance (HI) conditions. The absorption efficiency factors at red absorption peak, Q _a (675), were determined by reconstruction with intracellular chlorophyll a concentration and cell diameter. The normalized Q _a (675) also showed diel pattern with maximum toward midday and minimum toward dawn or dusk under LI. The diel pattern in a*_pico (675) and Q _a (675) were primarily caused by changes in intracellular chlorophyll a concentration due to photoadaptation under LI. The diel pattern in a*_pico (443) was influenced by pigmentation, as recognized by blue to red ratio [a*_pico (443)/a*_pico (675)] under HI. This study proposed that the opposite diel pattern in a*_pico (γ) might occur for a wide range of algal species. The results presented here have important consequences for the interpretation of diel variations in optical properties observed in the open ocean.     

均匀层浅海声场与海底反射损失的关系

海底对浅海声传播的影响很大。海底有复杂的多层结构。在计算声场时如果把多层海底的影响都考虑进去,就会使计算复杂化,得不出一个清晰的物理图象。因此,在计算中往往使用海底反射损失系数来代替多层海底的模型。但海底反射损失与角度有复杂的依赖关系。为了计算方便,提出过不少简化模型。已经使用的模型有反射损失与角度无关、与角度一次方成正比;后来又提出反射损失在某一临界角之下与角度一次方成正比,在临界角之上与角度无关的三参数模型,克服了远场与近场衔接的问题[1,2]。但这些模型不一定在所有情况下都能反映海底反射损失与角度的关系的主要特征。本文提出一个近似方法,可以计算海底反射损失按任意规律随角度单调上升的情况下的声场。