氮、硫供应水平对芜菁硫代葡萄糖苷含量的影响

硫代葡萄糖苷（GS）含量的多少是芜菁品质好坏的重要指标。本文采用沙培试验、 高效液相色谱法（HPLC）研究不同氮（80 kg/hm2、 160 kg/hm2和240 kg/hm2）和硫（10 kg/hm2和60 kg/hm2）供应水平对白玉芜菁叶和根中硫代葡萄糖苷组成和含量的影响。结果表明, 白玉芜菁叶片中有7种硫代葡萄糖苷,根中有9种硫代葡萄糖苷。叶片中总硫代葡萄糖苷含量是根部总硫代葡萄糖苷含量的1.16倍。增加硫供应水平,显著增加了根和叶中各种硫苷含量;随着氮供应水平的增加,吲哚族硫苷含量占总硫苷含量的比例显著增加。白玉芜菁中硫代葡萄糖苷的含量决定于氮和硫的平衡供应,在氮N 160 kg/hm2、 硫S 60 kg/hm2供应水平下硫代葡萄糖苷含量最高。     

基于FLUENT的高含硫天然气管道泄漏扩散模拟

利用CFD软件FLUENT首次对高含硫天然气管道破裂泄漏扩散规律进行了数值模拟,得到了甲烷、硫化氢在一定风速、地形条件影响下的扩散规律,以及甲烷和硫化氢的浓度分布规律,为有效预测高含硫天然气泄漏扩散的影响范围提供了依据。研究结果对于认识高含硫天然气泄漏扩散规律以及相关安全事故的预警和救援具有指导意义。     

SO2毒害水稻叶片吸收光谱植被指数研究

为寻找对SO_2伤害敏感的叶片吸收光谱植被指数,通过田间熏气试验对水稻叶片吸收光谱与叶绿素总量、熏气浓度的相关性进行了研究.结果表明,由吸收光谱曲线及其一阶导数光谱曲线的特征位置确定的分别位于蓝光区、黄光区和红光区的12个特征波段的叶片吸收光谱值均与叶绿素总量显著相关,由这些特征波段构建的植被指数BEACI/YEACI/REACI与叶绿素总量的相关性都达到极显著水平,并且相关系数比特征单波段吸收光谱值与叶绿素总量的相关性显著提高.进一步分析这些植被指数与SO_2熏气浓度之间的相关性表明,最新完全展开叶在663.239、693.460 nm的单波段吸收光谱以及植被指数BEACI、REACI、YEA CI613.385、YEACI_(630.036)和YEACI_(663.239)与SO_2熏气浓度呈正显著相关.BEACI、REACI,、YEACI_(613.385)、YEACI_(630.036)和YEACI_(663.229)为叶片吸收光谱SO_2伤害敏感植被指数,具有估测水稻SO_2伤害的应用潜力.     

Sulfur mineralization in two soils amended with organic manures,crop residues,and green manures

The mineralization of sulfur (S) was investigated in a Vertisol and an Inceptisol amended with organic manures, green manures, and crop residues. Field‐moist soils amended with 10 g kg^—1 of organic materials were mixed with glass beads, placed in pyrex leaching tubes, leached with 0.01 M CaCl₂ to remove the mineral S and incubated at 30 °C. The leachates were collected every fortnight for 16 weeks and analyzed for SO₄‐S. The amount of S mineralized in control and in manure‐amended soils was highest in the first week and decreased steadily thereafter. The total S mineralized in amended soils varied considerably depending on the type of organic materials incorporated and soil used. The cumulative amounts of S mineralized in amended soils ranged from 6.98 mg S (kg soil)^—1 in Inceptisol amended with wheat straw to 34.38 mg S (kg soil)^—1 in Vertisol amended with farmyard manure (FYM). Expressed as a percentage of the S added to soils, the S mineralized was higher in FYM treated soils (63.5 to 67.3 %) as compared to poultry manure amended soils (60.5 to 62.3 %). Similarly the percentage of S mineralization from subabul (Leucaena leucocephala) loppings was higher (53.6 to 55.5 %) than that from gliricidia (Gliricidia sepium) loppings (50.3 to 51.1 %). Regression analysis clearly indicated the dependence of S mineralization on the C : S ratio of the organic materials added to soil. The addition of organic amendments resulted in net immobilization of S when the C : S ratio was above 290:1 in Vertisol and 349:1 in Inceptisol. The mineralizable S pool (S_o) and first‐order rate constant (k) varied considerably among the different types of organic materials added and soil. The S_o values of FYM treated soils were higher than in subabul, gliricidia, and poultry manure treated soils.     

4种金色叶树木对SO2胁迫的生理响应

近年来 SO₂污染比较严重,它对植物有着多方面的影响。因此,越来越多的学者开始关注这方面的问题。彩叶植物在丰富园林景观及降低环境污染方面占用重要的地位,它们也被认为是净化城市空气最有效的途径之一。 旨在阐明4种彩叶树种耐SO₂污染机制,对丰富植物耐SO₂研究的理论、科学评价植物抗SO₂污染能力以及指导园林绿化科学选择树种等具有重要理论和现实意义。研究采用人工模拟熏气的方法对金叶女贞、金叶莸、金叶风箱果和金叶红瑞木4种金色叶树种的2年生苗木进行不同浓度的 SO₂ 胁迫,研究了参试树种的外观受害症状及膜脂过氧化、渗透调节物质、保护酶活性等生理指标对 SO₂ 的反应,并采用模糊数学隶属函数法和灰色关联度法对其抗SO₂能力进行了综合评价。结果表明: 4种金色叶植物对 SO₂ 均具有一定的净化能力,表现为随着 SO₂ 浓度的增加膜透性增大,丙二醛、脯氨酸、可溶性糖和硫含量增加,超氧化物歧化酶、过氧化物酶以及过氧化氢酶活性上升,叶绿素含量先增后降,叶液 pH 值下降。但4种金色叶树木对 SO₂ 的净化能力有差别,其中金叶红瑞木的净化能力强最大,金叶女贞和金叶风箱果的净化能力为中等,而金叶莸的净化能力最差。这与其含硫量的顺序一致,却与其对SO₂的抗性大小即金叶女贞> 金叶莸> 金叶红瑞木>金叶风箱果完全不同,说明这四种植物对 SO₂ 的吸收能力与其对该气体的抗性不完全一致。但这不能表明抗性差的树种在兰州地区不能应用,因为,兰州市空气中的SO₂实际污染程度与研究所设置的最低浓度相比仍属安全浓度。在所选的10个指标中,丙二醛含量、细胞膜透性、超氧化物歧化酶活性、过氧化氢酶活性、脯氨酸、过氧化物酶活性、叶绿素和可溶性糖等指标均可作为金色叶植物对 SO₂ 抗性的重要鉴定指标,而S含量和叶液 pH 值在评价植物对SO₂抗性能力时并不具有重要性。4种植物的受害程度与其SO₂抗性相反,说明受害症状可以作为判断其对SO₂抗性大小依据。     

SO_2排放对葫芦岛地区土壤的影响

在葫芦岛地区 ,由于锌厂常年 (尤其是近期 )排放SO2 已使该区土壤性质受到了严重的影响 .测定结果 :土壤表层 ( 0～ 2 0cm)有效S提高 1～ 5倍 ,全S含量提高 2 1 .38%～ 87.86% ,在严重影响区 pH值已下降至 5 .0 5～ 5 .0 3.锌厂排放的SO2 所形成的酸雨危害不可忽视     

Use of contrast-enhanced ultrasound for characterization of focal splenic lesions.

Contrast-enhanced ultrasound was used to study focal and multifocal lesions of the spleen in 26 dogs and two cats affected by 11 benign and 18 malignant splenic diseases. A second-generation microbubble contrast medium (Sonovue) was injected into the cephalic vein and enhancement patterns were subjectively described and time intensity curves calculated. Final diagnosis was obtained by histopathologic examination after splenectomy (n=19) or by needle aspiration and sonographic follow-up after 4 and 8 weeks (n=9). Contrast-enhanced ultrasound parameters, improving the characterization between benign and malignant lesions, were established. The most useful criterion was the hypoechogenicity of the lesion in the wash-out phase combined with the presence of tortuous feeding vessels, which was observed in association with malignancy. All malignant lesions were hypoechoic to the surrounding spleen 30s after starting the contrast medium injection. Lymphosarcoma and hemangiosarcoma had characteristic perfusion patterns. Lymphosarcoma had rapid time to peak and early wash-out phase with a honeycomb pattern during the wash-out. Hemangiosarcomas were large nonperfused masses in all phases surrounded by hypervascular splenic parenchyma. Benign lesions except one hematoma and a benign histiocytoma had the same perfusion pattern as the surrounding spleen. Ultrasonographic and contrast-enhanced ultrasound findings of an accessory spleen are reported. Contrast-enhanced ultrasound can improve the characterization of focal or multifocal lesions of the spleen.     

不同小麦品种氮、硫积累特性与子粒品质的关系

依据小麦子粒含硫量和N/S比值的差异,用聚类分析的方法,将供试的12个小麦品种分为3 组:高N/S比组、中N/S比组和低N/S比组。研究不同类型小麦氮硫积累特性及其与子粒品质的关系,结果表明,小麦植株的氮素积累量与硫素积累量呈极显著正相关,氮素收获指数与硫素收获指数之间无显著线性相关关系。高N/S比组品种具有较高的氮素积累量或氮素收获指数,但硫素收获指数或硫素积累量相应较低;中N/S比组品种氮素收获指数高,硫素收获指数亦高;低N/S比组品种硫素积累量和硫素收获指数均较高,但氮素收获指数较低,植株体积累的氮素和硫素在子粒中分配比例的不同是品种间子粒N/S比值差异的重要原因。不同N/S比组品种比较,子粒谷蛋白含量、谷蛋白含量与醇溶蛋白含量比值、面团形成时间和稳定时间存在显著差异,且与子粒N/S比值呈极显著二次曲线关系,适宜的N/S比有利于子粒谷蛋白的积累及子粒品质的形成。     

Effect of Sulfur on the Yield and Essential and Nonessential Element Composition of Alfalfa Determined by Polarized Energy Dispersive X‐ray Fluorescence

Alfalfa crops were grown in the field at the University of Ankara (473939 E, 4385149 N), over two seasons between 2001 and 2003 with sulfur (S) supplied at two different rates. The experimental design was a randomized complete block with five replicates and three cutting dates in each season. Sulfur was applied at rates of 0 (control), 160 (S₁), and 240 (S₂) kg ha^?1 as gypsum. Alfalfa hay was harvested three times each year, and the concentrations of elements in the hay were measured by polarized energy dispersive x‐ray fluorescence (PEDXRF). Sulfur fertilization increased S concentrations and improved alfalfa hay yield for both years. Applied S slightly reduced phosphorus (P) and magnesium (Mg) concentrations in the first year and had no significant effect on the potassium (K) and calcium (Ca) concentrations of alfalfa hay for either year. The highest S (240 kg ha^?1 S) level increased sodium (Na) concentrations in the first year but decreased them in the second year. Sulfur application also decreased chloride (Cl) concentration in the first year. Molybdenum (Mo) concentration of the alfalfa was significantly reduced by S₁ treatment in year 1. Iron (Fe) concentration was increased by S₂ treatment in the second year, and zinc (Zn) concentration was increased by S₁ treatment in the first year. However, applied S had no effect on manganese (Mn), copper (Cu), titanium (Ti), vanadium (V), cobalt (Co), nickel (Ni), barium (Ba), uranium (U), and lead (Pb) concentrations for either year. Applied S decreased aluminum (Al) and silicon (Si) and increased bromine (Br) and rubidium (Rb) concentrations of alfalfa in the first year. In addition, strontium (Sr) concentration was increased by S₂ treatment in the first year but was decreased in the second year. The stage of cutting greatly affected mineral concentrations. Compared with the first cutting, S concentrations were higher in the second and third harvest for both years. In general, the concentrations of P, Mg, Na, Cl, Mo, Ti, V, Br, Co, Ba, Sr, Rb, U, and Pb were increased, whereas the concentrations of Fe, Zn, Mn, Cu, and Ni were decreased with later cutting. The concentrations of K and Ca did not vary between cuts.