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The presences of the common macroalgae Ulva sp. and Jania rubens vary between seasons along the Israeli Mediterranean intertidal zone. To reveal some of the potential acclimation mechanisms of these algae, we examined their photosynthetic traits during the year using rapid light curves (RLC) derived from pulse amplitude modulated (PAM) fluorometry. In addition, the relationships between those photosynthetic traits and the relative abundances of the two algae were investigated. Ulva sp. showed high maximal electron transport rates (ETRmax) (49.7–68.8 μmol electrons m−2 s−1) and onsets of light saturation values (Ek) (75.8–85.6 μmol photons m−2 s−1) in the winter months of December–February, while low values were found in the summer months of June–July (5.2–20.6 μmol electrons m−2 s−1 and 6.0–23.7 μmol photons m−2 s−1, respectively). At noon time (during the highest irradiance of the day), the maximal effective quantum yield (Y0) did not vary significantly during the year. These results indicate that seasonal irradiance influences the number of reaction centres per thallus area. Both algae showed depressions in Y0 at noon (23.8% for Ulva sp. and 20.3% for Jania rubens), indicating an efficient non‐photochemical quenching mechanism. A positive correlation between the relative abundance and the photosynthetic parameter Y0 was found for Jania rubens when Y0 was sampled in the morning or noon, indicating that growth rate and primary production for this alga can be estimated from RLCs. No such correlation was found for Ulva sp., indicating that, in addition to photosynthetic traits, the relative seasonal abundance of this alga is influenced by other factors such as grazing and/or catastrophic events. 相似文献
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有机锡对海洋微藻的生理效应
──Ⅱ.三苯基锡和三丁基锡对扁藻和金藻光合作用的影响
总被引:19,自引:1,他引:19于1991年4月-1992年1月,分别用不同浓度的三苯基氯化锡和三丁基氯化锡培养扁藻和金藻,测定24,48和72h两种藻的净光合速率和生长速率。结果表明,TBTC对两种藻的毒性大于TPTC;TPTC和TBTC在浓度为0.2μg/L时,对两种藻的光合作用有轻微影响;浓度大于0.4μg/L,两种藻的光合作用不同程序地受到抑制。扁藻对有机锡的耐受力大于金藻:扁藻用两种锡处理后,第一天受害最严重,第二天和 相似文献
156.
Mirinae Lee Heeju Park Nguyen Viet Tien Suk-Joo Choh Robert J. Elias Dong-Jin Lee 《《地质学报》英文版》2016,90(3):796-806
A new species of the probable calcareous alga Amsassia, A. koreanensis, is recognized from the Duwibong Formation (Middle Ordovician, Darriwilian) of the Taebaeksan Basin in mid-eastern Korea. This is the first report of the genus from the Korean Peninsula, expanding its geographical range to the eastern Sino-Korean Block. The new species also occurs in the Xiazhen Formation (Upper Ordovician, Katian) at Zhuzhai in the South China Block. Amsassia koreanensis is the smallest species of this modular genus, having a maximum module diameter of 0.28 mm. Module increase is by bipartite, tripartite and quadripartite types of longitudinal axial fission, but unlike other species of the genus, quadripartite fission is common. The types of fission are comparable to those in some Tetradiida (now Prismostylales, florideophycean rhodophyte algae), although the processes of fission are different. The distribution of A. koreanensis further strengthens the biogeographical connection between the Sino-Korean and South China blocks, suggesting that these two paleocontinents were located closer together during the Middle to Late Ordovician than previously speculated. 相似文献
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Paraelectrentomopsis chenyangcaii gen. et sp. nov. from the Cretaceous Burmese amber is characterized, described, illustrated and its position is discussed. This fossil taxon is the second compsocid barklouce to be described from the Burmese amber and constitute one of the earliest records of the family. A checklist of known Compsocidae is given. Identification keys of all known Compsocidae are provided. A palaeobiogeography scenario is proposed. 相似文献
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对4种假单胞菌产脓菌素培养基进行筛选,确定琥珀酸钠培养基为基础培养基,并考察了添加不同物质对假单胞菌脓菌素产量的影响,结果表明,向琥珀酸钠培养基中添加甘油、海盐、硝酸铵时对铁载体产量有明显的促进作用.采用正交实验法获得了高产脓菌素的最佳发酵培养基配方:4g/dm~3琥珀酸钠,6 g/dm~3K2HPO4,3 g/dm~3KH2PO4,1 g/dm~3(NH4)2SO4,1 g/dm~3NH4NO3,5 g/dm~3海盐,1.5%甘油.其脓菌素产量最高可达到265 mg/dm~3,约是基础培养基产量的7倍以上,此培养基成分简单不含复杂的有机氮源,脓菌素产量高,有利于脓菌素的进一步分离纯化与制备.同时本实验对其发酵条件进行优化研究,结果确定最佳发酵条件:培养基起始p H值为6.9,接种量1.0%,培养温度为25℃,转速为220 r/min,发酵时间为28 h. 相似文献
160.
海洋链霉菌由于其独特的生理和代谢功能,成为海洋微生物活性物质的主要来源。对2010-2013年初的海洋放线菌天然产物的统计表明,研究最多的是链霉菌放线菌,占海洋放线菌新天然产物的60%。本文综述了自1976年第一个海洋链霉菌天然产物到2016年6月的40年间报道的547个海洋链霉菌天然产物的结构、生物活性及其微生物来源。其结构包括含氮化合物(如生物碱)、聚酮、萜类、甾体等,其中含氮化合物是主要类型, 占海洋链霉菌天然产物总数的61%;而67%的海洋链霉菌天然产物表现出细胞毒、抑菌、抗疟和抗寄生虫等生物活性。 相似文献