Potassium additions on ionic equilibria,selectivity and diffusion of cations in soils

Abstract

In a soil system variation in the concentration of any one ion as induced by external addition might bring changes in the ionic‐equilibria, diffusion rate and strength of adsorption of all the ions involved. In four Indiana soils the changes in ionic equilibria, selectivity coefficient and rate of diffusion coefficient for K, Na, Ca and Mg were investigated at 5 levels of added K. The experiments were carried out under controlled laboratory conditions by incubating soils for 3 weeks at 25C. All soils had a greater fraction of Ca and Mg on the exchange phase than in solution, whereas with K and Na the reverse occurred. Potassium adsorption isotherms for all the soils differed indicating the difference in the nature of soil materials involved. Chalmers soil with high clay content with high exchange capacity had high differential buffer value for K. In all the soils, K was adsorbed preferentially to Na at all the levels of K addition, Calcium was adsorbed preferentially to Mg on the Zanesville and Toronto soils. However, in Chalmers and Raub soils, reverse was observed when the level of K addition was exceeded 1.0 and 0.5 me K/100g soil, respectively. This difference in Mg for Ca is attributed to smaller proportion of Mg saturation on the exchange surface. Divalent cations were preferentially adsorbed over monvalent ions. Increasing levels of K addition increased the diffusion rates of all the ions under consideration. The rate of diffusion for K and Ca were governed by concentrations of these ions on the exchange and solution phase.     

核桃离体培养中外植体褐化的研究

对核桃离体培养中外植体的褐变进行了初步研究，结果表明：4月份取嫩枝茎段进行培养，效果最差，褐变死亡率高，取6月份半木质化茎段进行培养，效果较好，休眠芽次之。液体状态的培养基可以减轻外植体褐变。培养基中附加激素6-BA和IAA、GA时，外植体的褐变程度较低，外植体腋芽萌发与生长分化较好。培养基中加入硫代硫酸钠对防止外植体褐变。提高外植体萌芽率和有效新梢率有促进作用。     

水稻不同基因型中Ca、Na对K的部分替代作用

以ＫｉｍｕｒａＢ为基本营养配方，通过改变钾强度，并按化学计量加Ｎａ或不加Ｎａ，加Ｃａ或不加Ｃａ，研究了籼稻不同基因型苗期的生物量和钾纱利用效率。结果表明，在低钾下，补充Ｃａ或Ｎａ时，所有基因型的钾素利用效率都显著提高，生物量则变化不大。     

过量表达甜菜BvNHX1基因提高拟南芥的耐盐性

Na+/H+逆向转运蛋白调节细胞内的离子平衡,在植物耐盐性起重要的作用。为了研究甜菜液泡膜Na+/H+逆向转运蛋白BvNHX1基因在植物耐盐中的作用,构建了植物表达载体pROKⅡ-BvNHX1转化拟南芥.在含有卡纳霉素的培养基上筛选转化子,并利用Southern和Northern杂交技术检测,进一步证实BvNHX1基因已整合到拟南芥基因组并能正常转录。选取纯合转基因株系进行耐盐性分析实验表明,过量表达BvN-HX1基因的拟南芥在种子萌发和苗期都提高了植株耐盐性,盐处理下转基因植株的鲜重、干重以及地上部分Na+、K+含量均高于野生型对照。结果表明过量表达BvNHX1基因提高了转基因拟南芥的耐盐能力。     

硫酸钠对油菜种子萌发和离体茎尖生长的影响

以2份高芥酸和2份低芥酸油菜(Brassica napus)品种为供体材料,观察了组织培养条件下,不同浓度Na2SO4溶液对油菜种子萌发和离体茎尖生长的影响.结果表明,随着硫酸钠浓度的提高,种子的发芽率和离体茎尖存活率总体呈下降趋势;高芥酸品种对Na2SO4耐受性优于低芥酸品种.     

欧亚旋覆花提取物对朱砂叶螨生物活性及其体内几种酶活性的影响

植食性害螨是危害农业生产的一个重要生物类群,我国每年用于主要作物的杀螨剂费用约90多亿元(师光禄等,1994)。朱砂叶螨(Tetranychus cinnabarinus)是其中一个重要的种类,可危害粮、棉、油、林木、果树等43科146种植物(李连昌等,     

早期断奶仔猪饲粮丙氨酰谷氨酰胺适宜添加量的研究

本文旨在研究丙氨酰谷氨酰胺(Ala-Gln)对早期断奶仔猪生长性能、血液生化指标和小肠黏膜酶活性的影响,探讨Ala-Gln在早期断奶仔猪饲粮中的适宜添加量.选用48头(公母各占1/2)纯种云南撒坝仔猪为试验对象,35日龄断奶,按单因素完全随机化设计分为4组,每组3个重复,每个重复4头猪.各组分别饲喂在基础饲粮上添加0(对照组)、0.15％、0.30％、0.45％ Ala-Gln的试验饲粮,试验期为35 ～ 60日龄.结果表明:1)0.30％组显著提高了全期仔猪平均日增重和平均日采食量(P＜0.05),随着Ala-Gln添加水平的提高,全期仔猪平均日增重和平均日采食量以二次曲线方式提高(P=0.004和P=0.006);2)0.30％组极显著提高了49日龄仔猪血清总蛋白、葡萄糖含量及谷丙转氨酶活性(P＜0.01),显著提高了血清碱性磷酸酶活性(P＜0.05),极显著降低了血清尿素氮含量(P＜0.01),显著降低了乳酸脱氢酶活性(P＜0.05).各组血清白蛋白、肌酐含量及肌酸激酶活性均差异不显著(P＞0.05).3)试验组仔猪空肠黏膜钠泵(Na+ -K+ -ATPase)和总二糖酶活性均显著或极显著高于对照组(P ＜0.05,P＜0.01).结果提示,添加适量的Ala-Gln对早期断奶仔猪具有一定的促生长效应,在本试验条件下,依据二次曲线拟合结果,推荐Ala-Gln适宜添加量为0.27％.     

Application of a fuzzy rule-based method for the determination of clay dispersibility

Some clay soils are highly susceptible to erosion and piping because of dispersion or deflocculation in pore water. These soils, called “dispersive clay soil” in geotechnical engineering, are structurally unstable, easily dispersive and, thus, highly erodible. There are many tests to determine dispersibility both physically and chemically. However, these tests can give different results for the same soil sample. Therefore, more than one test should be used to identify dispersive soils more accurately. In previous research, the discriminant method was used to combine these test results. In this study, a fuzzy logic approximation method was developed to combine the different results of the double hydrometer, pinhole, Na(%)-TDS and ESP-CEC methods into a single value. This new method was applied to the dispersibility test results of 29 samples, and it gave more reliable and objective results for identifying the dispersibility of the clay soil.     

钾、钠离子与液泡膜H~+-ATPase研究进展

介绍了植物液泡膜H+-ATPase分子结构和功能,尤其重点阐述了K+、Na+与植物液泡膜H+-ATPase活性的关系。     

NaCl、单Na~+、Cl~-盐胁迫对番茄叶片光合特性及蔗糖代谢的影响

为了研究Na+和Cl-对番茄产量和品质的影响,以栽培番茄品种辽园多丽为试材,分析了等渗的NaCl(50mmol/L)、Cl-盐和Na+盐胁迫对番茄光合特性及叶片中糖代谢的影响。结果显示,等渗的NaCl、Cl-盐和Na+盐胁迫均导致番茄叶片净光合速率下降,胁迫7d后分别较对照(hoag-land营养液)降低15.18%、6.23%和10.11%;3个胁迫处理均降低了番茄叶片的气孔导度、胞间CO2浓度和蒸腾速率,并降低了番茄叶片中叶绿素a和b的含量,以上光合参数的变化都是Na+盐处理的影响大于Cl-盐处理。在等渗的NaCl、Cl-盐和Na+盐胁迫下,番茄叶片中的果糖和葡萄糖含量较对照显著增加,Na+盐胁迫增加的幅度大于Cl-盐胁迫,而蔗糖和淀粉含量较对照有所降低;等渗的NaCl、Cl-盐和Na+盐胁迫增加了番茄叶片中的蔗糖转化酶活性,其中NaCl处理增加的最多,Na+盐胁迫次之。表明NaCl、Cl-盐和Na+盐胁迫均破坏了番茄叶片的光合机能,降低了光合作用效率,Na+的影响大于Cl-;NaCl、Cl-盐和Na+盐胁迫改变了番茄叶片中的糖代谢方向,显著促进了淀粉和蔗糖的分解,提高了叶片中的果糖和葡萄糖含量,Na+对番茄叶片中糖代谢的影响显著大于Cl-。