Influence of Ca/P ratio on the catalytic performance of hydroxyapatite for decarboxylation of itaconic acid to methacrylic acid

Methacrylic acid,an important organic chemical,is commercially manufactured starting from fossil feedstock.The decarboxylation of itaconic acid derived for biomass is a green route to the synthesis of methacrylic acid.In view of the problems existing in the researches on this route such as use of noble metal catalyst,harsh reaction conditions and low desired-product yield,we prepared a series of hydroxyapatite catalysts with different Ca/P molar ratios and evaluated their catalytic performance.The results showed that the hydroxyapatite catalyst with a Ca/P molar ratio of 1.58 had the best catalytic activity.The highest yield of MAA up to 61.2%was achieved with basically complete conversion of itaconic acid under the suitable reaction conditions of 1 equivalent of NaOH,2 MPa of N_(2),250℃,and 2 h.On this basis,a reaction network for the decarboxylation of itaconic acid to methacrylic acid catalyzed by hydroxyapatite was established.With the aid of catalyst characterization using X-ray powder diffraction,NH3/CO2 temperature-programmed desorption,N_(2)physisorption,inductively coupled plasma optical emission spectrometry,and scanning electron microscopy,we found that the distribution of surface acid sites and basic sites,crystal growth orientation,texture properties and morphology of hydroxyapatite varied with the Ca/P molar ratio.Furthermore,the change of the crystal growth orientation and its influence on the surface acidity and alkalinity were clarified.

Calcium-Magnesium Ca/Mg Ratios and Their Agronomic Implications for the Optimization of Phosphate Fertilization in Rainfed Rice Farming on Acidic Ferralsol in the Forest Zone of Ivory Coast

This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosphorus (P) nutrition of rice on these acidic soils, where this nutrient constitutes a limiting factor for agricultural production. Three (3) pot trials were conducted in Adiopodoumé in the forested south of Côte d’Ivoire. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg Ca ha−1) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha−1) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha−1 of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha−1) and potassium (K) (50 kg KCl ha−1) were added to each of the tests in a split-plot device. The test results revealed a paddy production potential of approximately 3 to 5 t⋅ha−1 for NERICA 5 on an acidic soil, under the effect of the interaction of P, Ca and Mg. The quadratic response of rice yield to the doses of these fertilizers would be more dependent on their balance, itself influenced by Ca nutrition. For the sustainability and maintenance of rice production in agro-ecology studied, it was recommended doses of 38 kg Ca ha−1, 34 kg Mg ha−1 in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha−1, overall in a ratio 1/1/1 (P/Ca/Mg) more favorable to the availability of free iron considered a guiding element of mineral nutrition. Thus, these promising results should be confirmed in a real environment for better management of the fertilization of rice cultivated on acidic plateau soils in Côte d’Ivoire.

Effects of Regulation of C/N Ratio Wheat Straw Application on Nitrogen,Phosphorus and Potassium Uptake in Tobacco

[Objective]The aim was to study the effects of regulation of C/N ratio wheat straw application on tobacco nitrogen,phosphorus and potassium uptake. [Method]Effects of regulation C/N ratio wheat straw application on the flue-cured tobacco yield,output value,nitrogen,phosphorus and potassium content and cumulative uptake of the upper,middle and bottom leaf were studied by using the field plot experiments at Banqiao town,Qujing city,Yunnan Province during the 2008-2009 summer growing seasons. [Result]The results showed that the application of wheat straw alone or after C/N regulation,could significantly increase tobacco production,potassium content,the potassium and nitrogen accumulation amount of leaf,and was more conducive to the potassium uptake of tobacco leaf with wheat straw application after C/N regulation. Compared with non-straw application,the yield of tobacco increased by 6.59%,3.58%,5.98%,8.80% with application of wheat straw alone,wheat straw and vetch,wheat straw and oilseed cake,wheat straw and urea nitrogen,the potassium content in tobacco leaf increased by 3.85%,7.76%,8.82%,11.21%,respectively,the total potassium cumulative amount of leaf increased by 10.71%,11.62%,15.32% ,21.01% and the total nitrogen cumulative amount increased by 9.76%,1.22%,8.14%,14.00%. However,the differences of tobacco leaf nitrogen content among the different treatments were not significant,the phosphorus uptake of tobacco leaf decreased. [Conclusion]application of high C/N ratio wheat straw in flue-cured tobacco production,which should be concerned not only to adjust C/N ratio by adding nitrogen,but also considering additional phosphorus application.

乳腺癌超声图像特征与P53、PIK3CA蛋白表达状态相关性的研究

目的通过观测乳腺癌的超声图像特征,分析其与P53、PIK3CA蛋白表达的相关性。方法回顾性分析2022年1月—2023年10月本院经病理证实为乳腺癌的101例女性患者的临床资料,在获取病理前均行超声检查。二维超声用于观察乳腺癌大小、形态、边界、纵横比、后方回声以及有无微钙化,彩色多普勒超声用于观察病灶内部以及周边的血流情况。采用SP免疫组化法检测P53、PIK3CA蛋白的表达情况,分析其与超声图像特征的相关性。结果101例乳腺癌患者的临床病理资料显示,P53、PIK3CA的蛋白表达情况与乳腺癌病理亚型均具有相关性(χ^(2)=9.259、P=0.026,χ^(2)=7.927,P=0.048)。在超声图像特征中,血流强度、病灶后方回声衰减与P53蛋白表达具有相关性;病灶最长直径、病灶形态与PIK3CA蛋白表达具有相关性。P53蛋白表达阳性患者病灶血流信号丰富组(χ^(2)=8.191,P=0.004)和存在后方回声衰减组(χ^(2)=11.279、P<0.001)均高于阴性者,PIK3CA蛋白表达阳性患者声像图中的最长直径小于阴性者(t=2.132,P=0.036),而PIK3CA蛋白表达阳性患者病灶形态不规则比例(χ^(2)=4.551、P<0.033)高于阴性者。多因素Logistic回归表明,富血供是P53蛋白表达的影响因素,OR值为2.35[95%CI(1.11,5.74)];病灶形态不规则是PIK3CA蛋白表达的影响因素,OR值为4.58[95%CI(1.35,18.48)]。结论乳腺癌超声图像特征与P53、PIK3CA蛋白表达具有相关性,可以为临床诊疗乳腺癌提供重要的价值。

Preliminary determination of calcium,phosphorus,and the calcium/phosphorus ratio in cortical bone of Chinstrap penguin using synchrotron X-ray fluorescence analysis

Synchrotron radiation X-ray fluorescence （SR-XRF） approach was applied to analyzing of Chinstrap penguin （ Pygoscelis Antarctica） cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that ： （ 1 ） there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters （ on a dry-weight basis） are： 30.7% （Ca） and 14.9% （P） for the femoral cortical bone, 21.4% （Ca） and 11.5% （P） for wing cortical bone. （2） The variation for the Ca/P ratio in cortical bone is lower than those for Ca and P separately. This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish norreal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders.

CRISPR/Cas9系统介导的p53基因突变促进树鼩骨骼肌卫星细胞的增殖活性

目的:利用CRISPR/Cas9系统在树鼩骨骼肌卫星细胞中敲除p53基因并检测其增殖活性。方法:通过生物信息学方法对树鼩和15种哺乳动物的p53蛋白氨基酸序列进行同源性分析,根据树鼩基因组信息设计可编辑树鼩p53突变位点sgRNA,构建lenti CRISPR v2-sgp53基因编辑重组质粒,用293T细胞进行慢病毒包装,感染树鼩骨骼肌卫星细胞,嘌呤霉素筛选多克隆细胞并扩增;通过测序确定基因编辑效果。采用CCK8法检测细胞增殖活性,采用western blotting验证p53蛋白表达水平。结果:与人p53和小鼠p53氨基酸序列同源性(96.92%)相比,人p53和树鼩p53的氨基酸序列同源性(98.21%)更高。进化树分析显示,与小鼠相比,人与树鼩的亲缘关系更近。成功构建了3个靶向树鼩p53编辑的重组载体:lenti CRISPR v2-sgp53-g1、lenti CRISPR v2-sgp53-g2、lenti CRISPR v2-sgp53-g3,均成功在树鼩骨骼肌卫星细胞上实现p53基因编辑产生突变,导致p53功能丧失,p53的突变提高了树鼩骨骼肌卫星细胞的增殖能力。经药筛后的树鼩骨骼肌卫星细胞p53基因敲除成功,p53蛋白表达水平显著降低(P<0.01)。结论:本研究利用CRISPR/Cas9系统成功使树鼩骨骼肌卫星细胞p53基因突变、功能丧失,为后续树鼩p53基因敲除模型的建立提供了重要的分子生物学基础。

Comparison of foliar nutrient concentrations between natural and artificial forests of Pinus sylvestris var. mongolica on sandy land, China

In order to examine the causes of degradation of Pinus sylvestris var. mongolica plantations on sandy land, the foliar concentrations of N, P, K and C were analyzed and compared between the field grown P. sylvestris var. mongolica trees from two provenances （natural forests and plantations）. The results indicated that natural tree needles had lower N, P and C concentrations, and higher K concentrations than those of plantation tree needles. For plantation tree needles, ratios of N： P, P. K and N： K increased with tree age before 45 years old; but they were not clear for the natural tree needles. Compared with the conclusions reported on Pinus spp., we found that the foliar N and P concentrations were in the optimal range for both natural and plantation tree needles. This result suggested that N or P might not be the absolute limit factors in plant nutrient for P sylvestris var. mongolica on sandy land. However, foliar K concentrations in both natural and plantation tree needles were much lower than those reported on Pinus spp. （〉4.80 g kg-1）.The N： P ratio of natural needles was in the adequate ranges, but N： P ratio of plantation needles was out of the adequate ranges. These results indicated that there was a better balanced nutrition status in the natural forest than in the plantations. If only considering the foliar nutrient concentrations of P sylvestris var. mongolica from different provenances, it might be concluded that the degradation phenomenon of P. sylvestris var. mongolica plantations was not induced by nutrition deficiency of absolute nutrients of N and P, but might be induced by other mineral nutrients or by the effectiveness of N and P nutrients. The unbalanced nutrition status and relatively quick decomposition of needles in the plantations might also contribute to the degradation.

Combined preoperative platelet-to-lymphocyte ratio and serum carbohydrate antigen 19–9 level as a prognostic factor in patients with resected pancreatic cancer

Background: Carbohydrate antigen 19–9(CA19-9) is the most frequently used tumor marker and serves as a prognostic indicator in patients with pancreatic cancer(PC). The platelet-to-lymphocyte ratio(PLR) is thought to be an inflammation-related serum marker. An elevated PLR represents increased inflammatory status and is associated with poor prognosis in patients with various cancers including PC. Methods: This study involved 103 patients with a histopathological diagnosis of pancreatic ductal adenocarcinoma who underwent pancreatectomy. The patients were assessed to determine the prognostic significance of the combination of the PLR and CA19-9 level. Results: Based on the receiver operating characteristic analysis results, the patients were divided into PLR H igh(PLR ≥ 129.1) andPLRLow(PLR < 129.1) groups and into CA19-9High(CA19-9 ≥ 74.0 U/mL) and CA19-9Low(CA19-9 < 74.0 U/mL) groups. The cumulative 5-year overall survival(OS) and disease-specific survival(DSS) rates significantly differed by both the PLR(PLR H igh group: 19.5% and 22.9%;PLRLow group: 39.1% and 45.9%) and CA19-9(CA19-9 H igh group: 19.1% and 25.6%;CA19-9Low group: 41.0% and 41.0%). We then divided the patients into Groups A(PLR L ow/CA19-9Low), B(PLR Low/CA19-9High or PLRHigh/CA19-9Low), and C(PLR H igh/CA19-9High). The cumulative 5-year OS rates in Groups A, B, and C were 44.0%, 31.9%, and 11.9%, respectively( P = 0.002). The cumulative 5-year DSS rates in Groups A, B, and C were 47.7%, 36.4%, and 16.8%, respectively( P = 0.002). Multivariate analysis revealed that the combination of the PLR and CA19-9 was an independent prognostic factor in patients with resected PC. Conclusions: The combination of the PLR and CA19-9 is useful for predicting the prognosis of patients with resected PC.

Seasonal dynamics of N:P ratio stoichiometry and Ca fraction for four dominant plants in the Alxa Desert

Desert plants take on unique physiologically adaptive mechanisms in response to an adverse environment. In this study, we determined the concentrations of leaf nitrogen(N), phosphorus(P), and calcium(Ca) fraction for dominant species of Artemisia ordosica, A. frigida, Calligonum mongolicum, and Oxytropis aciphylla in the Alxa Desert and discussed seasonal changes of their leaf N:P ratio and Ca fraction. The results showed that, from May to September, the N:P ratios of A. ordosica and C. mongolicum gradually and significantly increased, while those of A. frigida, and O. aciphylla had an increase trend that was not significant; the physiologically active Ca of A. ordosica and A. frigida increased significantly,while that of C. mongolicum and O. aciphylla decreased significantly. The physiologically inert calcium of C. mongolicum increased extremely significantly, while that of others was not significant. There was a significantly positive correlation between the N:P ratio and physiologically active Ca for A. ordosica, and the N:P ratio was significantly and negatively correlated with physiologically active Ca for O. aciphylla. These findings revealed that the physiological regulation mechanism was different for the plants either in earlier stage or later stage of plant-community succession.

Effects of COD to Phosphorus Ratios on the Metabolism of PAOs in Enhanced Biological Phosphorus Removal with Different Carbon Sources

To elucidate the phosphorus removal and metabolism under various COD / P ratio,a sludge highly enriched in PAOs was used to investigate the impacts of COD / P in batch tests under different carbon supply conditions. Acetate,propionate and a mixture of acetate and propionate at a ratio of 3 ∶ 1( COD basis) was used as carbon sources with the COD / P of 20,15,10 and 5. 0 g COD /gP,respectively. The minimum COD / P ratios for complete P removal were found to be 8. 24 g COD /gP for acetate,11. 40 g COD /gP for propionate and9. 10 g COD /gP for the 3 ∶ 1 mixture of acetate and propionate. Converted to a mass basis,all three cases had a very similar ratio of 7. 7 g VFA /gP,which represented a useful guide for operation of EBPR plants to identify possible shortages in VFAs. The trend in PHV accumulation during the anaerobic period along with the decrease of COD / P ratios suggested that,PAOs may use the TCA pathway for anaerobic VFA uptake to maintain the required NADH production with reduced glycogen degradation. During the aerobic phase,the glycogen pool was reduced but remained enough compared to the requirement for anaerobic VFA uptake,and the synthesis and degradation of glycogen was not the inhibition factor of PAOs.

A 1000-year record of Mg/Li and Li/Ca ratios of ostracod shells in Lake Qinghai,NE Tibetan Plateau

1 Introduction Lake Qinghai,famous as the largest inland saline lake in China,located on the high-altitude northeastern Tibetan Plateau,and four junctional zones of the East Asian summer monsoon(EASM),Indian summer monsoon(ISM),East Asian winter monsoon and the westerly jet stream prevail,making it sensitive to global climate change

Knockdown of lncRNAXLOC＿001659 inhibits proliferation and invasion of esophageal squamous cell carcinoma cells

BACKGROUND Studies have shown that long non-coding RNAs(lncRNAs)play a key role in almost all key physiological and pathological processes,including different types of malignant tumors.Our previous lncRNA microarray results have shown that lncRNA XLOC_001659 is upregulated in esophageal cancer(EC)tissues,with a fold change of 20.9 relative to normal esophageal tissues.But its effect and the molecular biological mechanisms on proliferation and invasion of EC cells remain unclear.AIM To investigate the effect of lncRNA XLOC_001659 on esophageal squamous cell carcinoma(ESCC)cells and explore the molecular biological mechanisms involved.METHODS RT-qPCR assay was used to quantify the expression levels of lncRNAXLOC-001659 and miR-490-5p.The proliferative capacity of the cells was determined using CCK8 and colony formation assays,and the effect of lncRNAXLOC-001659 on the invasion of ESCC cells was determined by Transwell assay.Dualluciferase reporter assay was used to detect the target genes of lncRNAXLOC-001659 and miR-490-5p.RESULTS The results of RT-qPCR showed that the expression of lncRNAXLOC_001659 was upregulated in ESCC cells.CCK-8 assay showed that knockdown of lncRNAXLOC_001659 significantly inhibited ESCC cell proliferation.Colony formation and Transwell invasion assays showed that knockdown of lncRNAXLOC_001659 or overexpression of miR-490-5p significantly inhibited ESCC cell growth and invasion.Furthermore,lncRNAXLOC_001659 acts as an endogenous sponge by competitively binding to miR-490-5p to downregulate miR-490-5p.Further results confirmed that miR-490-5p targeted PIK3CA,and the recovery of PIK3CA rescued lncRNAXLOC_001659 knockdown or miR-490-5p overexpression-mediated inhibition of cell proliferation and invasion,which suggested the presence of an lncRNAXLOC_001659/miR-490-5p/PIK3CA regulatory axis.CONCLUSION Knockdown of lncRNA XLOC_001659 inhibits proliferation and invasion of ESCC cells via regulation of miR-490-5p/PIK3CA,suggesting that it may play a role in ESCC tumorigenesis and progression.

Efficient removal of Al(Ⅲ)and P507 from high concentration MgCl_(2)solution based on in-situ reaction strategy

For a highly efficient recycling of a wastewater containing a high concentration of MgCl_(2),Al(Ⅲ)and P507 were scheduled to be removed in advance.In this study,the in-situ removal of Al(Ⅲ)and P507 from a high concentration MgCl_(2)solution at different pH values and Al/P molar ratios was investigated.The results showed that P507 formed organic complexes of Al_(x)(OH)_y^(Z+)-P507 at pH of 2.0-4.0.At pH of 4.0-5.0,Al(Ⅲ)precipitated and transferred into Al(OH)_(3)with a flocculent amorphous morphology.Active sites on the Al(OH)_(3)surface enhanced the removal efficiency of P507.At pH of 6.0-6.5,Al(Ⅲ)and Mg(Ⅱ)formed layered crystalline Al(OH)_(3)and MgAl_(2)(OH)_(8with)small pore channels and fewer active sites,resulting in a reduced removal efficiency of P507.When the Al/P molar ratio exceeded 13 and the pH was between 4.0 and 5.0,the removal rates of both Al(Ⅲ)and P507 were higher than98%,while the concentration loss of Mg(Ⅱ)was only 0.2%-0.9%.

P53、CA125半衰期、HE4在上皮性卵巢癌预后中的研究进展

早期卵巢癌(OC)由于缺乏有效的监测指标,通常在晚期才被诊断出来,而早期OC生存率明显高于晚期,晚期OC总体5年生存率约为47%,而对于占比最高的上皮性卵巢癌(EOC),5年生存率则不到30%。目前EOC的主要治疗方案包括规范的分期手术、减瘤术及术后辅助化疗,但预后不佳,容易出现化疗耐药及术后复发,因此选择更有意义的指标来评估EOC病人的恢复情况,提高病人的生存率尤为重要。近年来研究发现癌组织中P53的表达、血清中癌抗原125(CAl25)含量的变化及人附睾蛋白4(HE4)的含量在EOC患者的预后中有较好的预测效果,本文就P53、CAl25半衰期及HE4在EOC预后中的研究进行综述。

Scaling of Soil Carbon,Nitrogen,Phosphorus and C:N:P Ratio Patterns in Peatlands of China

Inspired by the importance of Redfield-type C:N:P ratios in global soils,we looked for analogous patterns in peatlands and aimed at deciphering the potential affecting factors.By analyzing a suite of peatlands soil data(n = 1031),mean soil organic carbon(SOC),total nitrogen(TN) and total phosphorous(TP) contents were 50.51%,1.45% and 0.13%,respectively,while average C:N,C:P and N:P ratios were 26.72,1186.00 and 46.58,respectively.C:N ratios showed smaller variations across different vegetation coverage and had less spatial heterogeneity than C:P and N:P ratios.No consistent C:N:P ratio,though with a general value of 1245:47:1,was found for entire peatland soils in China.The Northeast China,Tibet,Zoigê Plateau and parts of Xinjiang had high soil SOC,TN,TP,and C:P ratio.Qinghai,parts of the lower reaches of the Yangtze River,and the coast zones have low TP and N:P ratio.Significant differences for SOC,TN,TP,C:N,C:P and N:P ratios were observed across groups categorized by predominant vegetation.Moisture,temperature and precipitation all closely related to SOC,TN,TP and their pairwise ratios.The hydrothermal coefficient(RH),defined as annual average precipitation divided by temperature,positively and significantly related to C:N,C:P and N:P ratios,implying that ongoing climate change may prejudice peatlands as carbon sinks during the past 50 years in China.

基于p38 MAPK信号通路探讨生慧颗粒对AD模型大鼠EC与CA1区影响及作用机制

目的观察生慧颗粒对东莨菪碱致痴呆模型大鼠EC与CA1区影响,基于p38 MAPK信号通路探讨其作用机制。方法40只SD大鼠随机分为空白组、模型组、生慧颗粒组、多奈哌齐组4组,使用东莨菪碱进行造模处理。使用Morris水迷宫及旷场实验对大鼠认知及焦虑行为进行评价。使用HE染色观察EC与CA1区神经损伤。使用c-Fos免疫荧光染色观察EC与CA1区神经元活性。使用Western blot对p38MAPK通路相关蛋白进行检测。结果行为学实验发现生慧颗粒可以改善AD模型大鼠认知障碍及焦虑样行为。HE染色结果表明生慧颗粒对EC与CA1区具有保护作用。c-Fos免疫荧光染色结果表明生慧颗粒可提高EC与CA1区神经元活性。Western blot结果发现生慧颗粒可以下调海马Bax蛋白表达及p38、Tau磷酸化水平,提高Bcl-2蛋白表达。结论生慧颗粒对AD模型大鼠EC与CA1区均具有保护作用,可能通过p38MAPK信号通路起到治疗作用。

Effects of soil nitrogen:phosphorus ratio on growth rate of Artemisia ordosica seedlings

To address how the ratios of nitrogen and phosphorus (N:P ratios) in soil affect plant growth, we performed a two-factor (soil available N:P ratios and plant density) randomized block pot experiment to examine the relationships between soil N:P ratios, and the N:P ratios and growth rate of Artemisia ordosica seedlings. Under moderate water stress and adequate nutrient status, both soil N:P and plant density influenced the N:P ratios and growth rates of A. ordosica. With the increase of soil N:P ratios, the growth rates of A. ordosica seedlings decreased significantly. With the increase of soil N:P ratios, N:P ratios in A. ordosica seedlings increased significantly. While the nitrogen concentrations in the plant increased slightly, the phosphorus concentrations significantly decreased. With the increase of plant density, the shoot N:P ratios and growth rates significantly decreased, which resulted from soil N:P ratios. Thus, soil N:P ratios influenced the N:P ratios in A. ordosica seedlings, and hence, influenced its growth. Our results suggest that, under adequate nutrient environment, soil N:P ratios can be a limiting factor for plant growth.

Effects of N:P ratio of Artemisia ordosica on growth influenced by soil calcium carbonate

Soil calcium carbonate(CaCO_3) has a strong solid phosphorus effect, and high content of CaCO_3 can significantly reduce the effectiveness of soil phosphorus. To reveal the limiting effect of soil CaCO_3 on the growth of plants on sand land and its mechanism of plant physiology, we performed pot experiments with a two-factor randomized block design and a three-factor orthogonal design for different soil CaCO_3 content treatments using Artemisia ordosica seedlings. In the experiments, we surveyed plant height, aboveground biomass, root length and root weight and analyzed N, P concentrations and RNA content of the seedlings, and discussed the relationships between relative growth rate(RGR) of the seedlings and N:P ratio as well as RNA. Results show that, the RGRs of plant height and above-ground biomass of the seedlings decreased significantly with the increase of soil CaCO_3 content, and those for root length and root weight decreased. The RGRs of plant height and above-ground biomass of the seedlings were significantly negatively correlated with leaf N:P ratios, but significantly positively correlated with leaf RNA content and leaf P concentrations. It can be seen that soil CaCO_3 is a stress factor for the growth of A. ordosica seedlings, and the growth response of the seedlings under the influence of soil CaCO_3 is in line with the Growth Rate Hypothesis.

STUDIES ON THE PHOSPHORUS REQUIREMENT AND PROPER CALCIUM/PHOSPHORUS RATIO IN THE DIET OF THE BLACK SEA BREAM(SPARUS MACROCEPHALUS)

An experiment on the phosphorus requirement and the proper Ca/P ratio in the diet of the black sea bream using the phosphorus gradient method (with casein as basic diet, sodium dihydrogen phosphate as source of phosphorus, and calcium lactate as source of calcium) showed that growth was greatly affected by the diet’s phosphorus content and Ca/P ratio. Inadequate phosphorus in the diet resulted in slow growth and poor food conversion ratio (FCR). Analyses of the fish body showed it contained a high level of lipid but a low level of moisture, ash, calcium and phosphorus. The optimal values of phosphorus and Ca/P ratio in the black sea bream diet are 0.68% and 1:2 respectively. Phosphorus in excess of this optimum value resulted in slow growth or even death. The results of this experiment clearly indicated that phosphorus is the principal mineral additive affecting black sea bream growth.

Coral Ba/Ca and Mn/Ca Ratios as Proxies of Precipitation and Terrestrial Input at the Eastern Offshore Area of Hainan Island

Geochemical ratios in coral reef skeletons could be used as proxies to reconstruct past climatological and environmental records in data-poor regions. Using a 103-year data set(1902 to 2005), the annual variations in Ba/Ca and Mn/Ca ratios of Porites lutea skeletons at an eastern offshore area of Hainan Island(19?12'28.4''N, 110?37'38.8''E) were analyzed using inductively coupled plasma-optic emission spectrometry(ICP-OES). The analysis results showed that Ba/Ca ratios varied from a minimum of 3.120 μmol mol^(-1) in 1903 to a maximum of 10.064 μmol mol^(-1) in 1944, with an average of 5.256 μmol mol^(-1). Mn/Ca ratios varied from 0.206 to 5.708 μmol mol^(-1) with an annual average of 1.234 μmol mol^(-1), with peak values in 2001, 1964 and 1932, that correlated with strong rainfall events caused by typhoons. Variation in Ba/Ca and Mn/Ca ratios were compared with available river discharge and precipitation records, providing insight into past climatological events. Human activities and their indirect effects could impact the strength of the relationship between Ba/Ca and Mn/Ca ratios and observed precipitation and terrestrial input in the future.