不同氮、磷、钾、钙水平对香水百合切花品质效应的研究

以盆栽香水百合为试验材料,用氮、磷、钾、钙四因素四水平L16(44)正交试验设计方法,测定了百合切花形态、瓶插寿命、花瓣中的超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、可溶性糖、可溶性蛋白质含量等指标,以期探讨配比施肥对香水百合切花品质的影响。结果表明,以施用氮肥300 mg/kg、磷肥100 mg/kg、钾肥150 mg/kg、钙肥120 mg/kg配比处理最佳,提高了百合的株高、花径叶面积,延长了切花瓶插寿命,维持了花瓣中SOD活性在较高水平,还减缓了瓶插期间花瓣中可溶性糖、可溶性蛋白质的下降。在瓶插3个时期内切花SOD活性、可溶性糖、可溶性蛋白质含量均与氮、磷、钙营养呈正相关,而与钾营养呈负相关。     

Kinetics of Hg adsorption onto noncrystalline Al hydroxide as influenced by low-molecular-weight organic ligands

This study was conducted to investigate the kinetics of Hg adsorption by noncrystalline Al hydroxide as influenced by various pH conditions and cysteine (cys), glycine (gly), and citric acid (cit), which have different structures and functionalities, as low-molecular-weight organic ligands using the GEOCHEM-PC software. The influence of these organic ligands on the kinetics of Hg adsorption varied according to their concentration, structure, and functionality and pH. The adsorption of Hg followed multiple first order kinetics with initial rapid adsorption, followed by slow adsorption. Cysteine suppressed or enhanced Hg adsorption, depending on pH and its concentration. Glycine and citric acid exerted suppressing and enhancing effects, respectively, with the exception of at pH 4.5 and at lower concentrations, at which no influence was observed as compared to the control. Two mechanisms were thought to mediate the adsorption of Hg(II); specific surface complexation in the control, cysteine and glycine systems, and ligand exchange in the citric acid system. The Hg adsorption at all levels of organic ligands decreased with increasing pH, with the exception of at the higher concentration of cysteine, at which the reverse trend was observed. The influence of organic ligands on the dynamics of Hg in the freshwater environment merits further study.     

Relationship between corn yield and chemical composition of the ear leaf measured with different regression models

Abstract

Corn yields and leaf samples were obtained from experimental plots receiving varying rates of N, P and K. Yields were regressed on leaf levels of N, P, K, Ca, Mg, B, Cu, Fe, Mn and Zn as independent variables. Various polynomial regressions were fitted to the yields and “goodness of fit”; of particular mathematical models was used as a basis for evaluating particular biological and statistical concepts.

It was found that no regression, where chemical elements were used as ratios, fit the observations as well as a quadratic polynomial or its square root transformation. This suggests that within the set of data used, emphasis on particular cation or anion ratios does not necessarily result in the “best”; explanation of variation in yield.

“Classical”; growth equations were fitted to corn yields, but were not as precise in predicting yields as the polynomials. A modified stagewise regression procedure was used for fitting one mathematical model, but results were less satisfactory than those obtained with usual least squares procedures.     

Calcium requirements for peanuts

Abstract

Surface soils from ten soil series representing five great groups were collected from Alaska. These soils were selected from the important agricultural areas covering a wide geographic distribution. These soils can be divided into two distinct groups based on their parent material: loess and volcanic ash. Phosphorus sorption maxima were calculated based on the Langmuir isotherms. The volcanic ash soils (Cryandept and Cryorthods) showed an average P‐sorption maxima of 10,122 mg/kg and loess soils averaged 3,934 mg/kg. Both groups have similar portions of phosphorus in the organic form (19%) and occluded form (8 to 9%). The nonoccluded‐P in the volcanic ash soils and the loess soils was 68% and 43% respectively, and the Calcium‐P was 4% and 29% respectively.

Regression analysis indicated that aluminum and iron are primarily responsible for P‐sorption. The dithionite extractable Al is responsible for P‐sorption in volcanic ash soils, while oxalate extractable Al is responsible for P‐sorption in loess soils. Dithionite and oxalate extractable Fe probably play a secondary role in P‐sorption. The sorption isotherm, regression analysis and the P‐fractionation data provide the agronomist with useful information to estimate P requirement of newly cleared soils.     

Effect of dimethylarsenic acid (DMAA) on growth,tissue arsenic,and photosynthesis of rice plants

The effect of dimethylarsenic acid (DMAA) applied to the root on arsenic (As) uptake and concentration, net photosynthesis (Pn), and growth parameters of rice (Oryza sativa L. cv. ‘Mercury') plants was studied. The experiment consisted of four treatments (0, 0.2, 0.8, and 1.6 mg As/L) with four replications in a completely randomized design. The DMAA was applied in nutrient solution as its sodium salt. The solution culture was changed every four days to avoid changes in the As chemical form. Arsenic uptake and concentration in shoot and root increased upon increased DMAA concentration in solution. Upon uptake, DMAA was readily translocated to the shoot. At the two higher rates of DMAA application (0.8 and 1.6 mg As/L), Pn and photosynthetic capacity were significantly decreased in response to tissue As concentration. Leaf area and dry matter production were also significantly reduced at the two higher rates of DMAA. At the lower rate (0.2 mg As/L) of DMAA application, there was no significant reduction in Pn or growth. Dimethylarsenic acid application did not affect nutrient allocation within the rice plant at concentration levels used in this study.     

Al2O3含量对烧结初始液流动行为的影响

在铁矿粉烧结过程中,初始液相流动行为是烧结矿固结效果的重要影响因素。采用微型烧结法,探讨了Al2O3含量对初始液相流动行为的影响,并通过对初始液相微观结构的解析,揭示了Al2O3含量对初始液相气孔分布和结构的影响规律。实验结果表明,初始液相的流动性指数随着Al2O3含量提高而降低。水淬试样的XRD实验结果结果证实,Al2O3含量的增加提高了复合铁酸钙的稳定性,降低了初始液相的流动能力。此外,初始液相流动性亦会对气孔性质产生影响。高Al2O3初始液相中气孔结构不规则程度提高,且小于50 μm气孔数目也随之增多。     

Effect of the Silicic Acid Polymerization Degree on the Coagulating Property of Polyalumium Silicate Chloride

Polyaluminum silicate is a new type of inorganic macromolecular flocculants, which is developed as a complex product in recent years on the base of polyalumium flocculant and polysilicic acid flocculant. Sodium silicate is diluted to the concentration of 3.0% SiO 2 with distilled water. The solution was adjusted to pH 4.5 with sulphate acid and kept at quiescency for different time to get polysilicic acid with different polymerization degrees. Using polysilicic acid prepared and aluminium chloride as materials, a series of polyaluminium silicate chlorides(PASC) with different basicities(B), Al/Si molar ratios and polymerization degree of silicic acid are prepared by copolymerization technique. The Al-Ferron timed complex colorimetric method is applied to characterize species distribution of PASC and to study its influence factors. The interaction between hydrolyzed aluminum species and polysilicic acid with different polymerization degrees in PASC is discussed.The flocculant prepared is applied to the treatment of commercial concrete wastewater. The turbidity removal of commercial concrete wastewater is up to 97% when a PASC, prepared with polysilicic acid of 145 min polymerization degree.     

黎榆A繁殖母本有效穗和结实率与产量的关系

繁殖田母本有效穗和结实率是影响产量的主要因素。通过对10个不同父母本栽插行比的分析结果表明：黎榆A繁殖产量以父母本栽插行比为2：18最高，达292．09kg/667m^2。增加有效穗对于增产的效应要比增加结实率大；有效穗与产量，结实率与产量的偏相关系数均呈正相关，且有效穗与产量的相关达显著水平，多元回归方程为：y-155.6283 4.8660x 0.2342x2.     

钙肥对金秋梨果实生理特性的影响

与健康果相比，金秋梨病果全钙、水提取态和1mol/L NaCl提取态钙含量减少，病果的N／Ca比、果胶甲脂酶（PEA）活性、超氧化物歧化酶（SOD）活性、过氧化物酶（POD）活性及丙二醛（MDA）含量较高。幼果期喷钙能显著增加平均单果重，降低发病率，改善果实品质，并可增加果实全钙，水提取态和1mol/L NaCl提取态钙组分，能降低果实N／Ca比、PEA、SOD、POD活性及MDA含量。     

赤霉素与Ca2+对水分胁迫下棉花种子发芽的影响

本试验分析了赤霉素和Ca2 对适当水分胁迫下棉花种子发芽的影响,通过对幼苗长度、发芽率、发芽势、发芽指数、活力指数等五个指标的测定,结果表明:赤霉素和Ca2 混合液对水分胁迫下棉花种子的发芽指标均有显著影响,其中以lmg/L赤霉素与8mmol/LCa2 混合效果最佳.