增强的UV-B辐射对地木耳中抗逆性物质的影响

实验室条件下模拟兰州地区夏至臭氧层衰减12％、20％和40％时增强的UV-B辐射2.54kJ·m-2·d-1(T1)、4.25 kJ·m-2· d-1 (T2)和8.35 kJ·m-2·d-1(T3),研究了不同强度的UV-B辐射对陆生蓝藻地木耳（Nostoc commune）中的的抗逆性物质光合色素（叶绿素a、类胡...     

Photosynthetic characteristics of sinking microalgae under the sea ice

The photosynthetic characteristics of sinking a microalgal community were studied to compare with the ice algal community in the sea ice and the phytoplankton community in the water column under the sea ice at the beginning of the light season in the first-year sea ice ecosystem on the Mackenzie Shelf, in the western Canadian Arctic. The phytoplankton community was collected using a water bottle, whereas the sinking algal community was collected using particle collectors, and the ice algal community was obtained by using an ice-core sampler from the bottom portion of ice core. Photosynthesis versus irradiance (P-E) incubation experiments were conducted on deck to obtain the initial slope (α^B) and the maximum photosynthetic rate (P_m^B) of the three algal communities. The α^B and the P_m^B of the light saturation curve, and chlorophyll a (Chl a) specific absorption coefficient (ā_ph*) between the sinking microalgal community and the ice algal community were similar and were distinctly different from the phytoplankton community. The significant linear relationship between α^B and P_m^B, which was obtained among the three groups, may suggest that a photo-acclimation strategy is common for all algal communities under the low light regime of the early season. Although the sinking algal community could be held for the entire duration of deployment at maximum, this community remained photosynthetically active once exposed to light. This response suggests that sinking algal communities can be the seed population, which results in a subsequent phytoplankton bloom under the sea ice or in a surface layer, as well as representing food for the higher trophic level consumers in the Arctic Ocean even before the receding of the sea ice.     

漳江口桐花树叶片光合色素含量和叶绿素荧光参数与盐度的关系

对生长在漳江口红树林湿地国家级自然保护区不同盐度环境中（FZ1：7.95-10.00;FZ2：11.10-15.25;FZ3：15.60-20.08;FZ4：20.58-23.54）优势红树植物桐花树的光合色素含量和叶绿素荧光特征进行了研究,结果表明盐度最低的样地FZ1比其他样地具有更高的叶绿素a、叶绿素b和胡萝卜素含量（p〈0.05）.Fv/Fm、Fv/F0和PIABS表现出同样的规律：FZ1、FZ2较高,尤其FZ1最高,与FZ3、FZ4有极显著水平差异（p〈0.01）.叶绿素荧光诱导动力学曲线（O-J-I-P）起始部分变化不大,其余部分均是FZ3比其他3个样地低.比活性参数ABS/CS、TRo/CS各样地间无显著差异;ETo/RC、RC/CSo是FZ3比其他样地下降,尤其是与FZ1、FZ2有极显著差异.DIo/CS则是FZ3比其他样地高,尤其是与FZ1、FZ2有极显著差异.这些结果表明,在保护区内盐度7.95‰-15.25‰环境中的桐花树叶片光合色素含量较高,光合器官对光能的吸收、转化和利用效率更高.     

Growth and survival of Halimione portulacoides stem cuttings in heavy metal contaminated soils

The halophytic shrub Halimione portulacoides demonstrates a high tolerance to heavy metal contamination and a capacity for accumulating metals within its tissues. On the Iberian Peninsula, this species has colonized habitats with high levels of metal pollution. The aim of this study is to analyze the response of H. portulacoides stem cuttings to this pollution. Growth, photosynthesis and metal uptake were examined in H. portulacoides through an experiment in which stem cuttings were replanted in metal-contaminated soil. This condition decreased growth and lowered both photosynthetic rate and stomatal conductance. Reduced photosynthetic performance was largely due to the reduced concentration of photosynthetic pigments. Despite these responses, there was some important evidence suggesting the phytoremediatory potential of Halimione stem cuttings. The results of our study indicate that this salt-marsh shrub may represent a biotool of value in the restoration of polluted areas.     

鼠尾藻(Sargassum thunbergii)固碳能力对流速的响应

流动的海水可以为海藻的生长提供所需的营养物质,对其生长和繁殖起到了非常重要的作用,而当前的生理生态学模拟实验,大多忽略了这一重要的环境因子.大型海藻虽然被认为是第4类"蓝碳",但关于其固碳能力的研究较少.本研究设计了一种可以调节流速的大型海藻固碳能力测量系统,既可以测量大型海藻的净光合速率、呼吸速率和对无机氮、无机磷的...     

西赤道太平洋暖池区光合色素分布及其对浮游植物群落的指示作用

利用光合色素的生物标志性可以在"纲"水平上表征浮游植物群落结构。依托大洋科学考察第20航次和21航次,通过对西赤道太平洋不同区域5个站位的HPLC藻类色素分析及CHEMTAX程序因子分析,获取了暖池区光合色素及浮游植物群落的垂直分布信息。结果显示在寡营养的暖池区,玉米黄素(Zeaxanthin)及乙二烯叶绿素a(DV Chl a)与叶绿素a浓度呈显著的正相关,浮游植物群落结构以蓝细菌、原绿球藻及定鞭金藻为优势藻纲,按对生物量的贡献率原绿球藻大于蓝细菌大于定鞭金藻的。蓝细菌和原绿球藻分布在真光层不同深度,而在营养盐丰富的次表层优势浮游藻类为定鞭金藻。     

Photosynthetic activity and antioxidative response of seagrass Thalassia hemprichii to trace metal stress

This study concerned the accumulation of trace metals in tissues of seagrass (Thalassia hemprichii) exposed to various concentrations of Zn²⁺+, Cd²⁺+, Pb²⁺+ and Cu²⁺+ for 10 d, and the effect of excessive metals on quantum yield (ΔF=F_m'), photosynthetic pigments and antioxidative enzymes like superoxide dismutase (SOD), guaiacol peroxidase (POD) were also examined. Cadmium was the most highly accumulated metal. Meanwhile, high metals levels led to a remarkable breakdown of photosynthetic parameters. Especially, ΔF=F_m', chlorophyll and carotenoid were significantly low during prolonged Cu exposure. Besides, ΔF=F_m' was more severely depressed by Cu and Zn than Pb and Cd. However, T. hemprichii had positive response by increasing the activity of SOD and POD. The results indicate that T. hemprichii is the most sensitive to Cu, and the antioxidative protection mechanisms of T. hemprichii are more efficiently activated to avoid damage of Zn, Cd and Pb stress. Finally, due to the high Cd-accumulation and strong Cd-tolerance capacity, T. hemprichii can be used for phytoremediation in Cd-contaminated areas.     

不同光质LED光源对黄瓜幼苗光合参数、水分利用效率和叶绿体超微结构的影响

采用发光二极管（LED）为光源,以白光作对照,研究了红光、蓝光和红蓝组合光对黄瓜品种“银胚99”幼苗叶片光合参数及水分利用效率的影响,并观察了叶绿体超微结构的变化。结果表明,蓝光和红蓝组合光均显著提高了叶片的净光合作用,在处理到第10天时,蓝光提高幅度最大,较白光高出27.29%;在处理到第20天时,红蓝组合光8R/2B提高叶片光合速率幅度最大,较白光高出56.94%。红蓝组合光处理下叶片的后期净光合速率下降较小,水分利用效率提高显著。与白光相比,红光处理对叶片净光合速率的影响不存在差异,且在处理第20天时叶片净光合速率和水分利用效率与第10天相比,有明显下降。叶片叶绿体超微结构显示,不同光质对黄瓜幼苗叶绿体发育有显著影响;白光不利于叶片叶绿体的成熟,红光造成叶片叶绿体淀粉粒过分积累,抑制了光合产物从叶片中的输出;红蓝组合光8R/2B和7R/3B处理则有利于叶绿体基质、基粒片层的形成和同化产物的输出。     

灌溉量对2种灌木光合特性和水分利用效率的影响

采用野外试验,研究了灌溉量对新疆策勒绿洲木沙拐枣（Calligonum mongolicum）和花棒（Hedysarum scoparium）光合特性和水分利用效率的影响。结果表明：（1） 随着灌溉量的增加,沙拐枣和花棒的净光合速率均增加,但是蒸腾速率、气孔导度、胞间CO₂浓度没有明显增加;（2） 灌溉增加了沙拐枣的清晨水势和正午水势,并且只有灌溉和无灌溉处理的正午水势差异显著（p<0.05）;而灌溉只增加了花棒的清晨水势,并且只有充分灌溉和无灌溉的条件下差异显著（p<0.05）;（3） 在不同的灌溉条件下,沙拐枣和花棒的稳定碳同位素比率δ¹³C变化不大,沙拐枣在无灌溉、适度灌溉、充分灌溉下δ¹³C的平均值分别为-12.267、-12.147、-11.958,花棒的δ¹³C分别为-27.928、-28.068、-27.166;（4） 沙拐枣和花棒的水分利用效率均在无灌溉条件下明显高于灌溉条件下,而且一次性的灌溉不会改变其水分利用效率。     

海洋微生物在船舶用结构钢表面附着成膜过程及其腐蚀研究

通过紫外分光光度计测定了海洋微生物需钠弧菌 Vibrio natriegens 的生长曲线,通过扫描电镜和原子力显微镜观测了该细菌在船舶用结构钢(DH32)钢样表面成膜过程及试样腐蚀形貌,探讨了生物膜的形成过程及其对材料表面腐蚀的影响。结果表明,生物膜的形成过程与微生物生命活动关系密切。根据对比暴露在菌液和无菌培养基中的试样表面形貌,发现细菌的附着及成膜过程的不均匀性,改变了DH32钢样表面的物理和化学状态。细菌附着区与周围形成的氧浓差电池,以及细菌新陈代谢主要产物对金属离子的络合,共同促进了试样局部腐蚀加速。