北亚热带3种典型森林群落对降水中氮、磷、硫的截留及分配特征

森林群落在净化空气、截留沉降污染物、改善地表水质等方面具有重要作用。本研究以北亚热带地区3种典型森林群落（毛竹林、杉木林、青冈阔叶林）为研究对象,通过分析沉降污染物（NH₄⁺-N、NO₃^--N、NO₂^--N、TP和SO₄^2-）在大气降水、林内穿透雨、树干茎流、枯透水和地表径流中的浓度和通量变化特征,探讨不同森林群落对氮、磷、硫的截留净化作用和分配特征。结果表明,该区域大气降水中NH₄⁺-N、NO₃^--N、NO₂^--N、TP和SO₄^2-年均浓度分别为1.06、0.61、0.04、0.07、1.84 mg/L,其年均pH为5.88;各森林群落林冠层能够调升降雨的pH且全年稳定,对TP和NH₄⁺-N均有吸附作用,截留率分别为79.09%-84.68%和30.88%-69.36%;而枯落物层则是林下氮、磷、硫的主要释放源,对NH₄⁺-N、NO₃^--N、TP和SO₄^2-均具有淋溶作用;此外,由地表径流（输出）与大气降水（输入）的对比分析可知,各林地对沉降污染物中氮、磷、硫的截留率均超过98%;3种森林群落对沉降污染物中氮、磷、硫的截留能力依次为：青冈阔叶林 > 毛竹林 > 杉木林,阔叶林对沉降污染物的净化能力要高于毛竹林及针叶的杉木林。     

中国西北典型冰川区大气氮素沉降量的估算——以天山乌鲁木齐河源1号冰川为例

高寒冰川区氮素沉降量的变化会对区域生态系统产生显著影响,定量评估冰川区的氮沉降状况可以为修正相关模型提供重要的原始数据。通过2004年1月至2006年12月在天山乌鲁木齐河源1号冰川连续采样,分析了中国西北典型冰川区大气氮素的沉降特征,并估算了该区域的年均氮素沉降量。研究结果表明,1号冰川湿沉降中的硝态氮 (NO₃^--N)、铵态氮 (NH₄⁺-N) 与总无机氮 (TIN) 存在着明显的季节变化特征:夏季沉降量最大,冬季最少,且与降水量表现出较好的对应关系。1号冰川氮素湿沉降的硝铵比 (NO₃^--N / NH₄⁺-N) 月平均值在0.3-1间波动。1号冰川TIN湿沉降量年平均值为1.51 kg/hm² (其中NH₄⁺-N沉降量占总量的69%,而NO₃^--N沉降量仅占31%),干湿沉降总量年均值为1.56 kg/hm²,总氮 (TN) 的干湿沉降总量年均值为3.85 kg/hm²。得到的冰川区氮素沉降量符合中国西部高寒区的一般水平,代表了该区域的本底值。     

温度和水分变化对冻土区泥炭地土壤氮循环功能基因丰度的影响

以大兴安岭多年冻土区泥炭地为研究对象,通过室内模拟增温实验,研究温度升高对不同深度（0-150 cm）土壤氮循环功能基因丰度的影响。同时针对0-20 cm和20-40 cm土壤设置两个水分处理,分别为土壤原始含水量和淹水状态,研究水分变化对表层土壤氮循环功能基因丰度的影响。结果表明温度升高显著提高了活动层（0-60 cm）、过渡层（60-80 cm）、永冻层（80-100 cm）中nifH、nirK基因丰度,温度升高显著提高了活动层（0-40 cm）和过渡层（60-80 cm）中nirS基因丰度。温度升高显著提高了过渡层（60-80 cm）NH₄⁺-N和较深永冻层（140-150 cm）NO₃^--N的含量,但降低了过渡层（60-80 cm）NO₃^--N和较深永冻层（120-150 cm）NH₄⁺-N的含量,相关性分析表明,NH₄⁺-N含量与nifH和nirS基因丰度呈显著正相关,NO₃^--N含量与nirK基因丰度呈显著正相关,说明温度升高能够通过改变微生物丰度促进过渡层固氮作用和反硝化作用。在增温条件下,淹水处理使表层土壤nirS和nirK基因丰度及NH₄⁺-N含量降低,但提高了NO₃^--N含量,说明淹水造成了过度还原的条件使反硝化底物浓度降低,降低反硝化微生物活性进而抑制了土壤反硝化作用。该结果对于明确未来气候变化影响下冻土区泥炭地土壤氮循环过程具有重要意义。     

氮素形态对杉木幼苗侧根生长和叶片光合特性的影响

以3月龄的杉木实生苗为试验材料,分析了不同氮素形态——硝态氮(NO₃^- N)、铵态氮(NH4⁺ N)和硝酸铵(NH₄NO₃)(氮素浓度均为3 mmol·L^-1)对杉木幼苗侧根生长、叶片光合气体交换参数和叶绿素荧光参数的影响,以揭示杉木幼苗对不同形态氮的偏好性,以及不同形态氮肥下杉木幼苗侧根生长和光合生理的响应特征,为杉木苗期氮肥管理提供理论依据。结果显示：(1)不同氮素形态对杉木幼苗地上部和侧根生物量具有显著影响,其中NH₄⁺ N处理下幼苗地上部和侧根生物量最大,NO₃^- N处理次之,而NH₄NO₃处理最小。(2)NH₄⁺ N和NO₃^- N处理下杉木幼苗总根长、根系总表面积和根系总体积均显著高于NH₄NO₃处理(P＜0.05),且NH₄⁺ N处理又显著高于NO₃^- N处理,但不同氮形态处理间侧根数量差异不显著。(3)NH₄⁺ N处理下杉木幼苗叶片净光合速率、气孔导度和蒸腾速率明显高于NO₃^- N和NH₄NO₃处理,但NO₃^- N和NH₄NO₃处理之间无明显差异。(4)NH₄⁺ N处理下杉木叶片初始荧光强度低于NO₃^- N处理,而最大荧光强度、可变荧光强度和PSⅡ潜在活性却高于全硝氮和硝铵氮处理。上述结果表明,NH₄⁺ N处理不仅有利于杉木幼苗侧根生长发育,且其叶片具有较强的光合能力,较高的PSⅡ中心稳定性、光化学活性以及电子传递效率,从而更有利于植株生长。因此,从根系生长和光合特性来看,杉木幼苗对铵态氮具有偏好性。     

一株耐碱变形假单胞菌ZY-3的鉴定及其脱氮特性

【背景】目前缺少具有高效脱氮能力、较高生物安全性、能处理高碱含氮污水的好氧反硝化菌株,难以使用生物方法处理高碱性的工业、养殖废水。【目的】对前期于佛山市一水产养殖池塘底泥中分离得到的耐碱高效好氧反硝化细菌ZY-3进行研究,期望获得一株能用于不同酸碱环境脱氮的高效、安全的好氧反硝化细菌。【方法】通过形态学、生理生化试验及16S rRNA基因序列分析方法对菌株种属进行鉴定,采用抗生素试验及斑马鱼攻毒试验进行菌株的环境生物安全性评估,利用3种含不同氮素的含氮模拟废水进行脱氮能力的测定。【结果】确定ZY-3为假单胞菌属变形假单胞菌（Pseudomonas plecoglossicida）,其对多种临床常用抗生素敏感,对水生生物的毒性低,该菌株在高浓度含氮模拟废水中以28℃、180 r/min振荡培养时,其对数期出现在4—12 h,在12 h时NH₄⁺-N、NO₃^--N和NO₂^--N的去除率分别达到94.87%、81.44%和98.02%,其pH耐受范围为6.0—10.0。【结论】得到一株安全、高效、具有广泛pH适应范围的耐碱好氧反硝化细菌P. plecoglossicida ZY-3,其在有氧条件下对3种氮素（NH₄⁺-N、NO₃^–-N、NO₂^–-N）具有快速去除能力。     

柠条锦鸡儿生物量分配规律与异速生长对氮、磷添加的响应

氮（N）和磷（P）元素在生态系统的结构和功能、稳定性、服务价值和可持续发展中起着关键作用。但自工业革命以来，全球气候变化受人类活动影响愈加剧烈。气候变化不同程度的影响干旱和半干旱区的氮磷循环过程，进而改变植物个体生物量积累以及植被生产力。因此，探究荒漠植物的生物量积累与分配规律对氮、磷添加的响应机制，有助于深入理解干旱区植物应对大气氮磷沉降等气候变化的适应策略。以荒漠植物柠条锦鸡儿（Caragana korshinskii Kom.，以下简称柠条）为研究对象，通过养分添加控制实验研究柠条地上/地下生物量的积累和分配，揭示其异速生长规律。实验包括3种形态的氮素添加（NH₄⁺、NH₄NO₃、NO₃^-）和1种磷素添加（H₂PO₄^-），分别对应4个浓度梯度（4 g/m²、8 g/m²、16 g/m²和32 g/m²）。结果表明，NO₃^-添加对柠条生物量有显著影响，但不同浓度对柠条生物量的影响无显著差异；单独的NH₄⁺添加对柠条地上/地下部分生长都具有显著抑制作用，且抑制作用与添加浓度呈显著的正相关关系；NH₄NO₃添加初期对柠条地上/地下生物量均具有促进作用，但这种促进作用会随着柠条生长和后期NH₄NO₃添加浓度的增加而消失；高浓度NH₄NO₃添加量（32 g/m²）会抑制柠条的生长。低浓度（4 g/m²、8 g/m²）外源氮添加会使柠条的生物量主要优先配给地下部分；磷添加则会使柠条的生物量分配策略向地上部分倾斜。综上所述，研究结果表明柠条改变地上和地下的生物量分配策略以响应氮或/和磷沉降。这一结论不仅增强了我们对植物生长策略的认识，而且有助于我们揭示全球气候变化条件下干旱地区土壤与植物之间的氮、磷循环和转化。     

蚂蚁筑巢对西双版纳热带森林土壤有机氮矿化的影响

蚂蚁作为生态系统工程师能够调节土壤微生物及理化环境,进而对热带森林土壤有机氮矿化速率及其时间动态产生显著影响。以西双版纳白背桐热带森林群落为研究对象,采用室内需氧培养法测定土壤有机氮矿化速率,比较蚁巢和非蚁巢土壤有机氮矿化速率的时间动态,揭示蚂蚁筑巢活动引起土壤无机氮库、微生物生物量碳及化学性质改变对有机氮矿化速率时间动态的影响。结果表明：（1）蚂蚁筑巢显著影响土壤有机氮矿化速率（P<0.01）,相较于非蚁巢,蚁巢土壤有机氮矿化速率提高了261%;（2）土壤有机氮矿化速率随月份推移呈明显的单峰型变化趋势,即6月最大（蚁巢1.22 mg kg^-1 d^-1、非蚁巢0.41 mg kg^-1 d^-1）,12月最小（蚁巢0.82 mg kg^-1 d^-1、非蚁巢0.18 mg kg^-1 d^-1）;（3）两因素方差分析表明,不同月份及不同处理对土壤有机氮矿化速率、NH₄-N及NO₃-N产生显著影响（P<0.05）,但对NO₃-N的交互作用不显著;（4）蚂蚁筑巢显著提高了无机氮库（NH₄-N与NO₃-N）、微生物生物量碳、有机质、水解氮、全氮及易氧化有机碳等土壤养分含量,而降低了土壤pH值;（5）回归分析表明,铵态氮和硝态氮对土壤有机氮矿化速率产生显著影响,分别解释87.89%、61.84%的有机氮矿化速率变化;（6）主成份分析表明NH₄-N、微生物生物量碳及有机质是影响有机氮矿化速率时间动态的主要因素,而全氮、NO₃-N、易氧化有机碳、水解氮及pH对土壤有机氮矿化速率的影响次之,且pH与土壤有机氮矿化速率呈显著负相关。总之,蚂蚁筑巢活动主要通过影响土壤NH₄-N、微生物生物量碳及有机质的状况,进而调控西双版纳热带森林土壤有机氮矿化速率的时间动态。研究结果将有助于进一步提高对土壤氮矿化生物调控机制的认识。     

亚热带次级森林演替过程中模拟氮磷沉降对土壤微生物生物量及土壤养分的影响

氮（N）沉降深刻影响着森林生态系统的生物多样性、生产力和稳定性。亚热带地区森林土壤磷（P）的有效性较低,N沉降将更突显P的限制作用。N、P输入对亚热带次级森林土壤的影响是否依赖于森林演替阶段知之甚少。选取两种不同演替年龄阶段（年轻林：<40 a;老年林：>85 a）的亚热带常绿阔叶林,设置模拟N和/或P沉降（10 g m^-2 a^-1）4个处理（Ctrl、N、P、NP）,连续处理4.5年后采集表层、次表层和下底层（0-15、15-30、30-60 cm）土壤样品,综合分析了土壤微生物生物量碳（MBC）氮（MBN）和多种土壤养分含量。结果表明,MBC、MBN及土壤养分含量均随土壤深度增加而降低。N添加对两种演替阶段森林土壤中MBC和MBN均无显著影响。施P相关处理（P和NP）对年轻林表层土壤MBC和MBN无显著影响,但显著增加了老年林表层土壤MBC和MBN（P<0.05）,表明老年林可能比年轻林更易受P限制。N添加显著增加了两种演替森林表层土壤可溶性有机氮（DON）、氨态氮（NH₄⁺-N）和硝态氮（NO₃^--N）的含量（P<0.05）;P相关处理（P和NP）显著增加两种演替阶段表层和次表层土壤速效磷（AP）以及表层土壤全磷（TP）的含量（P<0.05）。土壤MBC和MBN与土壤中各养分指标（可溶性有机碳DOC、DON、NH₄⁺-N、NO₃^--N、AP、全碳TC、全氮TN和TP）呈显著正相关关系,土壤TC、TN和DOC是影响土壤微生物生物量的主要因子。研究可为评估和揭示未来全球环境变化背景下不同演替林龄亚热带森林的土肥潜力及土壤质量的演变提供一定的科学理论依据。     

硝态和铵态氮配比对水培油麦菜苗期生长及生理特性的影响

采用水培技术,以油麦菜幼苗为材料,研究不同硝铵态氮配比（NO₃^-∶NH₄⁺）对油麦菜苗期地上部和根系生长及生理特性的影响。结果表明：（1）油麦菜地上部和根系硝酸盐含量皆与营养液中NO₃^--N比例呈正相关关系,且各处理均达到无公害蔬菜的标准。（2）随着营养液中NH₄⁺-N比例的增加,油麦菜地上部有机酸含量先降低后升高,且在硝铵态氮配比为5∶5时最低,可溶性糖含量呈上升趋势,而可溶性蛋白质含量先升高后降低,在硝铵态氮配比为5∶5时最高;油麦菜根系有机酸和可溶性糖含量先升高后降低,两者分别在硝铵态氮配比为5∶5和7.5∶2.5时最高,而可溶性蛋白质含量呈下降趋势,在全NO₃^--N时最高。（3）随着营养液中NH₄⁺-N比例的增加,油麦菜地上部和根系中SOD活性先升后降,并分别在硝铵态氮配比为5∶5和7.5∶2.5时最高,而地上部和根系中MDA、脯氨酸含量和POD、CAT活性的变化趋势则与其相反。（4）随着营养液中NH₄⁺-N比例的增加,油麦菜地上部和根系干重皆先升后降,根冠比则逐渐减小;在硝铵态氮配比为7.5∶2.5时干重最大,根冠比适宜且稳定。研究表明,水培油麦菜苗期地上部和根系生长及生理特性受到氮素形态配比的显著影响,且根系的生理响应更敏感;营养液中硝铵态氮配比为7.5∶2.5时,油麦菜受胁迫程度最低,地上部和根系生长较协调,油麦菜生长和生理状况最佳。     

丛枝菌根真菌和施加不同形态氮肥对杉木幼苗养分吸收的影响

为了解丛枝菌根真菌(AMF)和不同形态氮对杉木(Cunninghamia lanceolata)生长和养分吸收的影响,以1 a生杉木幼苗接种摩西球囊霉(Glomus mosseae)和添加不同形态氮(NH₄⁺-N和NO₃^–-N),对其养分元素和生长状况的变化进行研究。结果表明,AMF显著提高了杉木的苗高和生物量,促进了杉木对N、P、K、Ca、Mg、Fe和Na的吸收,AMF对微量元素Fe、Na的促进作用总体上要强于大量元素K、Ca。与NO₃^–-N相比,AMF显著提高了NH₄⁺-N处理杉木的生物量、总C和N、Ca、Mg、Mn含量,而且这种显著性在叶中普遍高于根和茎。接种AMF可以促进杉木幼苗的生长和对养分元素的吸收,且添加NH₄⁺-N处理的促进作用要强于NO₃^–-N。     

脱氮除硫菌株的分离鉴定和功能确认

从长期稳定运行的脱氮除硫反应器污泥中,分离获得两株具有脱氮除硫功能的芽孢杆菌。经形态观察、生理试验和16SrDNA序列比对,将两菌株归入芽孢杆菌属,菌株CB归类于Bacillus pseudofirmus,菌株CS则与Bacillus hemicellulosilytus和Bacillus halodurans最为接近。以Biolog板检测,菌株CB的基质多样性不明显,菌株CS则可利用Biolog板中多种碳源。菌株CB和菌株CS都能以硝酸盐氧化硫化物,其中菌株CB对硝酸盐、硫化物的转化能力大于CS,菌株CB对硝酸盐的亲和力也大于菌株CS。     

光学量,光子量和单位在激光生物学中的应用

激光生物学是光子学和生物学相结合的交叉边缘学科,根据《光及有关电磁辐射的量和单位》国际标准（ＩＳＯ／ＤＩＳ３１－６,１９９０）和我国国家标准（ＧＢ３１０２．６,１９９３）,本文讨论了在激光生物学中常用的光学量、光子量和单位。     

Effects of acute and chronic administration of secretin and caerulein on rat duodenal and gastric growth

We studied the effects of acute and chronic administration of secretin and caerulein, alone and in combination, on RNA and protein synthesis in the duodenum and oxyntic gland area as well as content of DNA, RNA and protein in rats. Secretin, 100 micrograms . kg-1, three times a day for 5 days, was associated with duodenal hypertrophy after the first 24 h of treatment and hyperplasia at the end of days 2 and 4; hypertrophy of the oxyntic gland area was observed only at 4 h after the first injection. Caerulein, 1 microgram . kg-1, also promoted duodenal hyperplasia after 2 and 4 days of treatment. The oxyntic gland area showed hypertrophy only at 4 h after the second injection of caerulein. These data indicate that both hormones can induce duodenal hyperplasia, probably by an amplification of the normal renewal cycle of the epithelial cells. They also demonstrated that growth of the oxyntic gland area is not promoted by these two peptides at the doses studied.     

Response and correlation of above- and below-ground functional traits of Leymus chinensis to nitrogen and phosphorus additions

AimsLeymus chinensis is a constructive and dominant species in typical steppe of northern China. The structure and functions of L. chinensis grassland ecosystem has been degenerated seriously due to long-term overgrazing in recent decades. As an effective measure to restore the degraded grasslands, the effects of nutrient addition on plant growth and ecosystem structure and functioning have been paid more attention in manipulation experimental research. The effects of nutrient addition, especially P addition on the above- and below-ground functional traits of L. chinensis have rarely been studied; particularly the underpinning mechanisms remain unclear. Our objective is to examine the responses and adaptive mechanisms of L. chinensis to different levels of N and P additions. MethodsWe conducted a culture experiment in the greenhouse, with three levels of N (50, 100 and 250 mg N·kg^-1) and P (5, 10 and 25 mg P·kg^-1) addition treatments. The above- and below-ground biomass, leaf traits (e.g., specific leaf area, leaf N and P contents) and root traits (e.g., specific root length, root N and P contents) of L. chinensis were determined in this study.Important findings Our results showed that: 1) the aboveground biomass and total biomass of L. chinensis were mostly affected by N addition, while the belowground biomass was mainly affected by P addition. N addition greatly enhanced the aboveground biomass of L. chinensis, while P addition reduced the belowground biomass at the moderate and high N levels. The root-shoot ratio of L. chinensis was influenced by both N and P additions, and root-shoot ratio decreased with increasing N and P levels. N and P additions promoted more biomass and N and P allocations to aboveground and leaf biomass. 2) Leymus chinensis showed different responses and adaptive mechanisms to P addition at low and high N levels. At low N level, L. chinensis exhibited high photosynthetic rate and specific root length (SRL) to improve photosynthetic capacity and root N acquisition, which promoted aboveground biomass. High root P content was favorable for belowground biomass. At high N level, P addition did not significantly affect plant growth of L. chinensis, even reduced its belowground biomass. Leymus chinensis showed high specific leaf area (SLA) and SRL to improve light interception and N acquisition in order to maintain stable aboveground biomass. 3) P addition greatly impacted below-ground than above-ground functional traits. SLA exhibited a weakly positive correlation with SRL, indicating L. chinensis exhibited relatively independence of resource acquirement and utilization between leaf and root functional traits.     

桃果实细胞内糖酸分布对果实甜酸风味的影响

以成熟‘白凤’桃果实为实验材料,采用区室化分析方法计算细胞内液泡、细胞质和细胞间隙中各糖酸组分的含量,并用调查问卷的方式对成熟桃果实甜酸风味进行评价打分,研究果肉细胞内各糖酸组分含量及其分布对果实甜酸风味的影响。结果表明:(1)成熟桃果实中可溶性糖(蔗糖、葡萄糖、果糖和山梨醇)在液泡、细胞质和细胞间隙的含量分别为27.3、11.6和9.0mg·g-1,有机酸(苹果酸、柠檬酸、奎宁酸和莽草酸)含量分别为2.09、0.94和0.35mg·g-1;蔗糖和苹果酸含量分别占果实可溶性糖和有机酸含量的80.6%和77.0%,是成熟桃果实中糖和酸的主要储存形式。(2)果实细胞内各糖酸组分通过细胞膜的渗透速率明显高于液泡膜。(3)块状处理桃果实液泡、细胞质与细胞间隙中的糖含量比、酸含量比及糖酸比分别为3.0∶1.3∶1.0、6.0∶2.7∶1.0、13.9∶12.4∶23.1,而匀浆处理果实的细胞结构被破坏,其不同细胞器中的比例分别为1.0∶1.0∶1.0、1.0∶1.0∶1.0、14.0∶14.0∶14.0;块状果实风味评价得分(2.99)明显高于匀浆处理果实(1.98)。研究认为,桃果实细胞中液泡、细胞质和细胞间隙之间糖酸含量以及糖酸比的差异可能是导致果实甜度风味变化的重要原因。     

Different effects of dark treatment on pigment composition and photosystem I and II activities in intact cotyledons and primary leaves of Cucurbita pepo (zucchini)

Darkness mediates different senescence-related responses depending on the targeting of dark treatment (whole plants or individual leaves) and the organs that perceive the signal (leaves or cotyledons). In this study, we presented data on the differential effects of 2-day dark treatment on progression of senescence in cotyledons and primary leaves of 14-day-old plants of Cucurbita pepo L. (zucchini). The lack of changes in chlorophyll a, chlorophyll b and carotenoid contents as well as in the PSI activity measured by the far-red induced alterations in the P₇₀₀ oxidation levels and the quantum yield of electron transport from Q _A ⁻ to PSI end acceptors () indicated higher resistance of cotyledons to the applied dark stress compared to the primary leaves. In contrast to cotyledons, PSI activity in the primary leaves was significantly inhibited. Concerning the activity of PSII analyzed by the changes in the JIP-test parameters (the maximal efficiency of PSII photochemistry, ; the performance index, PI_ABS; the efficiency of Q _A ⁻ reoxidation, ψ ₀ and the effective dissipation per reaction center, DI₀/RC), no differences were observed between cotyledons and primary leaves, thus suggesting that PSI activity in the true leaves was more susceptible to the applied dark stress. The transfer of the darkened plants to normal light regime resulted in delayed senescence in cotyledons which was in contrast to results on Arabidopsis, thus implying the existence of specific mechanisms of cotyledon senescence in different monocarpic plants.     

Free and ester-bound triterpene alcohols and sterols in cellular subfractions of Calendula officinalis flowers

In the chromoplast fraction and in the chromoplast-free fraction, obtained from Calendula officinalis ligulate flowers, the contents of individual free and ester-bound triterpene alcohols and sterols as well as the fatty acid components of the ester form were determined. It was shown that all sterols and triterpene monols in both forms occur in the two subtractions investigated, whereas all diols are localized only in the chromoplast fraction. The compositions of the fatty acids esterifying monols and sterols were similar to those esterifying diols in the chromoplasts. However, the fatty acids esterifying extra-chromoplast monols and sterols were different. This result indicates that triterpene monol esters are substrates for the biosynthesis of 3-monoesters of diols.     

关于苏北地区某三甲医院进口与国产医疗设备和耗材使用情况及反馈的研究．

目的：初步了解了进口与国产医疗设备与耗材的发展状况和使用反馈情况,并对国内医疗设备与耗材行业的发展提供合理化建议。方法：通过对苏北地区某三级甲等医院设备科工作人员、医生、护士长、患者及患者家属进行调研或访谈,并以调研和访谈的统计结果为依据得出结论并提出建议。结果：技术成熟的中小型医疗设备或耗材,从质量、价格等因素综合考虑,国内产品优于进口产品,一定程度上得到了医务人员和消费者的认可。在高端大中型医疗设备与耗材方面,进口产品具有较大的技术优势。结论：国内医疗设备生产企业应当积极开展研发工作,提高产品的技术含量与质量,巩固自身在中小型医疗设备与耗材方面的优势,并努力在高端大中型医疗设备与耗材方面取得突破。     

Mobility, solubility and lability of fluid and granular forms of P fertiliser in calcareous and non-calcareous soils under laboratory conditions

Despite a long history of application of phosphorus fertilisers, P deficiency is still a major limitation to crop production on calcareous soils. Recent field research conducted in highly calcareous soils in southern Australia has demonstrated that both grain yield and P uptake of wheat (Triticum aestivum L.) is greater when fluid forms of P are used compared to granular forms. To improve our understanding of the mechanisms underlying this response to P in the field, we compared the lability, solubility and mobility of P applied as either a fluid (3 products) or granular (3 products) form to two calcareous and one alkaline non-calcareous soils in the laboratory. Over a five-week period, between 9.5 and 18 % of the P initially present in the fertiliser granules did not diffuse into the surrounding soil. The degree of granule dissolution was independent of the soil type. In contrast, P solubility, lability and diffusion were significantly greater when fluid products were applied to the calcareous soils, but not to the alkaline non-calcareous soil. These findings are discussed in relation to field trials results where fluid products outperformed granular fertilisers.