盐胁迫下芦荟叶同化组织细胞中ATP酶活性超微结构定位及Si的作用

 利用电镜―细胞化学技术研究了盐胁迫下芦荟（Aloe vera L.）叶同化组织细胞中ATP酶（ATPase）分布特性及外源硅（Si）的作用。结果表明,正常生长情况下,芦荟叶同化组织细胞中液泡膜ATPase活性明显强于质膜ATPase,在细胞壁初生纹孔场观察到很强的ATPase活性。NaCl 100 mmol·L^-1处理30 d,浇灌的营养液中不加可溶性Si,芦荟叶同化组织细胞中液泡膜、质膜和初生纹孔场ATPase活性显著减弱,浇灌的营养液中加Si 2.0 mmol·L^-1处理,芦荟叶同化组织细胞中ATPase活性则显著增强,尤其是在液泡膜和初生纹孔场。叶同化组织细胞中ATPase活性的差异性反映着芦荟叶生理状态和功能的差异性,可溶性Si调节或增强盐胁迫下芦荟ATPase活性是Si缓解芦荟盐胁迫伤害效应的重要细胞生理机制。     

人工调节籼型杂交水稻不育系花时的研究

【目的】探索解决籼型杂交水稻不育系花时滞后、分散,制约其制种产量的方法。【方法】在大田条件下,以Ⅱ-32A、粤泰A和V20A等3个不同花时特性的籼型不育系为材料,对喷施“920”、茉莉酸甲酯（MeJA）及赶露水、喷施Na2SiO3等人工调节花时技术的效果进行比较。【结果】MeJA对所有供试材料均表现出提早花时和导致集中开花的显著效果,不同剂量的MeJA可使Ⅱ-32A、V20A的当日午前（12﹕15）累计开花数比对照提高2～5倍,累计开花率比对照提高20%～60%。并且其对花时不集中的不育系比对花时比较集中的不育系的调花效果更好。单独赶露水和叶面喷施Na2SiO3对调节不育系花时均表现出一定效果,而其与喷施MeJA对调花的协同效应更为明显。在合适剂量范围内,MeJA在调花的同时可显著促进柱头双边外露率和总柱头外露率的提高,但对开颖角度未表现明显作用。一般籼型杂交水稻不育系施用MeJA调花的合适剂量为30 mgm-2。【结论】以喷施MeJA为主的人工调节籼型杂交水稻不育系花时技术对提高其制种产量可能具有一定的潜力。     

等离子体制备纳米晶相氮化硅粉体的研究

为了提高氮化硅材料的弹性模量和烧结后的强度和韧度,通过感应耦合等离子体技术产生尘埃等离子体,采用SiH4和N2为反应气体,气相沉积Si3N4纳米粉体材料。利用朗缪尔探针技术测得沉积室中离子密度分布,获得气压为53Pa时,不同射频功率和不同位置处离子密度分布规律。通过TEM、IR和XRD技术对Si3N4纳米粉体材料微结构进行了分析。结果表明:尘埃等离子体技术制备的纳米Si3N4粉体材料为球形,均匀分布在20nm,并且具有β-Si3N4晶相。     

Network Structure and Its Strengthening for Fe-C-Si-Mn Alloys

Fe - C - Si - Mn alloys are used as blades in hydroelectric generators contained network structures after some heat treatments. It is found by metalograph and TEM analysis that annealed network structure is pearlite with very fine slice while the normalized is martensite or bainite. Experimental results together with theoretical analysis prove that the network structures are resulted from segregations of carbon and manganese atoms in the interdendritic areas, higher heat treatment temperature or longer soaking time can enlarge the grid size and finally eliminate the network structure. The network structure has some effects on the strength, and the smaller the grid size, the higher the strength.     

2007年6月荷兰姜荷花盆花最流行品种‘Siam Scarlet’

姜荷花Siam系列是2006年推出的品种，市场反映很好，很受消费者喜爱。Siam系列中品种花色各异，从深粉色到纯白色7个品种，苞片中深红色棱的犹如叶脉显得十分特别。而比起传统的姜荷花，Siam系列盆花体型小也成为一大优势，便于培育和运输。     

Ni-Co-P/Si3N4 electroless composite plating and its hardness

Ni-Co-P/Si3N4 composite coating on Al alloy is prepared by electroless composite plating in order to improve the minohardness of Al alloy. The influence of electroless plating process parameters on the micro-hardness of Ni-Co-P/Si3N4 coating on a hyper-eutectic Al-Si casting alloy is studied by an orthogonal experiment. The effects of process parameters, such as pH and mole ratio of Co 2+/（Co 2+ +Ni2+）,Si3N4 concentration in electroless plating bath and plating temperature,on the micro-hardness of composite layer are obtained. It is indicated that the hardness of coatings can be increased by increasing pH, plating temperature,Si3N4 concentration and keeping mole ratio of Co2+/（Co 2+ +Ni2+）moderate. Moreover, the influence of heat treatment on the micro-hardness of coatings is also investigated. It is found that the hardness of films increases with the heat treatment temperature rising below 400 ℃ but decreases when temperature is over 400 ℃.     

基于 Anycasting 的铝硅合金离心铸造数值分析

针对采用离心铸造方法制备自生初晶颗粒增强的铝基梯度复合材料过程中产生的宏观缺陷,以Anycasting为模拟软件,以Al-18Si-6Mg合金为研究对象,采用数值模拟和试验相结合的方式对卧式离心铸造的充型过程、温度场分布、卷气过程、氧化夹渣形成位置以及缩孔的形成进行了详细的分析.结果显示,针对该类铝合金,离心转速控制在1 000r/min左右时,铸件可以获得较好的外观形貌;同时,成型过程中的卷气是导致铸件形成气孔的主要原因.气孔与氧化夹渣的分布位置与充型过程、温度场分布以及铸型结构有关.而铸件轴向和壁厚方向上的双向凝固是造成缩孔的关键,如何解决成形过程中的双向凝固,是采用离心铸造制备自生增强铝基梯度复合材料有待解决的关键难题.     

中国云南省滇池盆地东南区由于土地利用方式的变化（从水田变为旱地或温室土壤）导致土壤理化性质的变化研究

Paddy fields in the southeastern basin of Dianchi Lake have rapidly changed to greenhouses since 1999. A total of 61 surface soil samples, including 43 greenhouse soils, 12 upland soils, and 6 paddy soils, were collected from a flat lowland area mainly used for agricultural production fields in the southeastern basin of Dianchi Lake. Analyses of the soil samples indicated that the greenhouse soils were characterized by a lower organic matter content, lower pH, and higher soluble nutrients than the paddy soils in the area. The lower organic matter content of the greenhouse soils was ascribed to environmental or management factors rather than the clay content of the soil. Accumulation of soluble nutrients, especially inorganic N, was due to over-application of fertilizers, which also caused soil acidification. The average amount of readily available N, P, and K accumulated in the greenhouse soils was estimated to be equal to or higher than the annual input of these nutrients as a fertilizer, indicating that a reduction in fertilizer application was possible and recommended. In contrast, a very low available Si content was observed in the paddy soils, suggesting the need for Si application for rice production.     

低分子量有机酸培养下几种层状硅酸盐矿物的变化

以两种低分子量有机酸(草酸、柠檬酸),三种层状硅酸盐矿物(高岭石、蒙脱石、伊利石)为材料,研究加入不同浓度有机酸(0 ～ 0.500 mol/L)恒温振荡培养3、7、15天后,各矿物的释硅(Si)量以及矿物结构的变化.研究表明:随着培养时间的增加,各浓度有机酸培养下高岭石和伊利石的释Si量在15天达到最大;在矿物相同的情况下,草酸培养体系大部分较相同浓度柠檬酸体系释放出的Si量高,Si的释放量在0.48 ～ 244.30 μg/ml(以SiO2计)之间;随着有机酸浓度的升高,各矿物Si的释放量均先升高后降低,在有机酸种类和浓度相同的情况下,蒙脱石释放出的Si量最高;随着有机酸浓度的升高,蒙脱石X射线衍射(XRD)图谱中特征峰的强度依次减弱,且草酸较柠檬酸作用效果显著,高岭石和伊利石的则无明显变化.