用激光诱导击穿光谱技术比较土豆和百合中的微量元素

激光诱导击穿光谱(LIBS)已成功地运用于固体、液体、气体样品中微量元素的测量以及微生物、细菌等的鉴别分析上,而在植物样品上面的应用则是一个较新的课题。该实验用纳秒Nd:YAG激光器击穿真空冻干的土豆、百合样品,用光纤光谱仪测量了其LIBS光谱。通过鉴别、分析LIBS光谱,得到了这两种样品中微量元素的成分。并且对土豆干和百合干中Ca,Na,K,Fe,Al,Mg六种金属元素典型谱线的强度进行了统计分析,并由此得到了样品中这六种微量元素含量的对比情况。实验结果表明土豆干中的Ca和Na等含量都明显高于百合干,而百合干中Mg的含量较高。实验结果还表明用LIBS技术检测、对比冻干植物样品中微量元素含量是一种快速、有效的分析方法。

Global iron connections between desert dust, ocean biogeochemistry, and climate

IEECAS SKLLQG

Microelements in Potato and Lily Samples Studied by Laser-Induced Breakdown spectroscopy Technology

A LIBS setup was built in the Institute of Modern Physics. In our experiments, LIBS spectra produced by infrared radiation of Nd : YAG nanosecond laser with 100 and 150 mJ pulse energy, respectively, were measured by fiber optic spectrometer in the ranges of 230-430 run and 430-1080 nm with a delay time of 1.7 and gate width of 2 ms for potato and lily samples prepared by vacuum freeze-dried technique. The lines from different metal elements such as K, Ca, Na, Mg, Fe, Al, Mn and Ti, and nonmetal elements such as C, N, O and H, and some molecular spectra from C-2, CaO, and CN were identified according to their wavelengths. The relative content of the six microelements, Ca, Na, K, Fe, Al, and Mg in the samples were analyzed according to their representative line intensities. By comparison we found that there are higher relative content of Ca and Na in lily samples and higher relative content of Mg in potato samples. The experimental results showed that LIBS technique is a fast and effective means for measuring and comparing the contents of microelements in plant samples.

参与肿瘤侵袭和转移的细胞外基质降解酶

肿瘤细胞在侵袭和转移过程中必需穿透一系列天然组织屏障—基底膜和细胞外基质。合成及分泌大量基质降解酶，降解细胞外基质是肿瘤细胞侵袭、转移的重要步骤［１］。目前所知与肿瘤侵袭、转移有关的基质降解酶有两大类：蛋白酶类和糖苷酶类，前者主要降解细胞外基质中的蛋...

番茄专用肥肥效初步研究

番茄专用肥肥效初步研究刘子江，崔桂霞，武冠云（中国科学院沈阳应用生态研究所）赵彩霞，张玉兴王述麟，王阳（沈阳市于洪区畜牧副食局）（沈阳市东陵区畜牧副食局）随着农业生产的发展和科学施肥技术的实施，专用肥的应用愈来愈广泛。专用肥的使用效果，是肥料研究领域...

氮磷配合对土壤氮素径流流失的影响

大田试验研究结果表明 :增施N、P均能增加作物的产量和减少水土流失 ;当N、P用量分别达到 5 5 .2kgN/hm2 和 90kgP2 O5/hm2 时 ,泥沙有机质和全氮流失最少 ,流失量分别为 2 0 89和 1 75kg/km2 ;当N、P用量分别为 5 5 .2kgN/hm2 和 4 5kgP2 O5/hm2 时 ,土壤矿质氮流失最小 ,其流失量仅为 2 7.9kg/km2 ;作物对土壤氮素的吸收 ,可减少土壤氮素的流失 .

硫化物的快速分光光度法测定

提出了测定微量硫化物的快速亚甲蓝分光光度法。实验结果表明：在硫酸溶液中， Ｋ２Ｃｒ２Ｏ７＋对二甲氨基苯胺＋Ｓ２－迅速显色反应形成亚甲蓝，表观摩尔吸收系数为４．０６×１０４ Ｌ·ｍｏｌ－１·ｃｍ－１；最大吸收波长为 ６６４ ｎｍ；线性范围为 ０～０．８ ｍｇ／Ｌ。实验了采用全差示光 度法直接测定水中硫化物的条件，用于某江水中２１．６ μｇ／Ｌ的硫化物测定时，相对标准偏差 为３．２％（ｎ＝６）；试样的标准加入回收率为９５％～１１０％。

Characterization of the main light-harvesting chlorophyll a/b-protein complex of green alga, Bryopsis corticulans

The main light-harvesting chlorophyll a/b -protein complex (LHC II) has been isolated directly from thylakoid membranes of shiphonous green alga, Bryopsis corticulans Setch. by using two consecutive runs of anion exchange and gel-filtration chromatography. Monomeric and trimeric subcomplexes of LHC 11 were obtained by using sucrose gradient ultracentrifugation. Pigment analysis by reversed-phase high performance liquid chromatography showed that chlorophyll a (Chl a), chlorophyll b (Chl b), neoxanthin, violaxanthin and siphonaxanthin were involved in LHC 11 from B. corticulans. The properties of electronic transition of monomeric LHC II showed similarities to those of trimeric LHC II. Circular dichroism spectroscopy showed that strong intramolecular interaction of excitonic dipoles between Chl a and between Chl b exist in one LHC II apoprotein, while the intermolecular interaction of these dipoles can be intensified in the trimeric structure. The monomer has high efficient energy transfer from Chl b and siphonaxanthin to Chl a similarly to that of the trimer. Our results suggest that in B. corticulans, LHC II monomer has high ordered pigment organization that play effective physiological function as the trimer, and thus it might be also a functional organization existing in thylakoid membrane of B. corticulans.

Evidences of the intertidal red alga Grateloupia turuturu in turning Vibrio parahaemolyticus into non-culturable state in the presence of light

Grateloupia turuturu, previously known as Grateloupia doryphora, has been widely reported to be an invasive algal species. There are no studies to relate the impact of its existence on its surrounding environment. In this paper, we present our results to show that about 70% of individuals collected from the field could turn Vibrio parahaemolyticus into non-culturable state on both selective (TCBS) and non-selective (2216E) culture medium in 24 h in the presence of light in live algal culture. Total bacteria counts on TCBS and 2216E plates dropped from the initial 565 (174) and 1192 (60) cfu ml(-1) respectively to zero in 24 h. This effect disappeared when the alga was grown in darkness. The same effect was not found in two other intertidal macroalgae Laminaria japonica and Palmaria palmata. Further tests showed that the settlement ability of bacteria in seawater was impaired significantly in the presence of this alga in comparison with three other algal species. (c) 2006 Elsevier B.V. All rights reserved.