Comparison of Seven Kinetic Equations for K Release and Application of Kinetic Parameters

Corn field experiments with two treatments, NP and NPK, where N in the form of urea, P in the form of calcium phosphate, and K in the form of KC1 were applied at rates of 187.5, 33.3, and 125 kg ha-1, respectively, on soils derived from Quaternary red clay were conducted in the hilly red soil region of Zhejiang Province, China. Plant grains and stalks were collected for determination of K content. Seven equations were used to describe the kinetics of K release from surface soil samples taken before the corn experiments under electric field strengths of 44.4 and 88.8 V cm-1 by means of electro-ultrafiltration (EUF) and to determine if their parameters had a practical application. The second-order and Elovich equations excellently described K release; the first-order, power function, and parabolic diffusion equations also described K release well; but the zero-order and exponential equations were not so good at reflecting K release. Five reference standards from the field experiments, including relative grain yield (yield of the NP treatment/yield of the NPK treatment), relative dry matter yield (dry matter of the NP treatment/dry matter of the NPK treatment), quantity of K uptake in the NP treatment (no K application), soil exchangeable K, and soil HNO3-soluble K, were used to test the effectiveness of equation parameters obtained from the slope or intercept of these equations. Correlations of the ymax (the maximum desorbable quantity of K) in the second-order equation and the constant b in the first-order and Elovich equations to all five reference standards were highly significant (P < 0.01). The constant a in the power function equation was highly significant (P < 0.01) for four of the five reference standards with the fifth being significant (P < 0.05). The constant b in the parabolic equation was also significantly correlated (P < 0.05) to the relative grain yield and soil HNO3-soluble K. These suggested that all of these parameters could be used to estimate the soil K supplying capacity and the crop response to K fertilizer.

Predictive and Comparative Study of Chromatographic Retention Index for 75 Chloronaphthalene Congeners

Chloronaphthalenes （PCNs, polychlorinated naphthalenes） are a group of persistent environmental pollutants. In the present study, geometrical optimization and electrostatic potential calculations have been performed for all 75 PCNs at the HF/6-31G^＊ level of theory. A number of statistic based parameters have been extracted. Linear relationships between gas-chromatographic retention index （RI） of 62 PCNs in a non-polar column （DB-5） and the structural descriptors have been established by stepwise multiple regression technique. The result shows that two quantities derived from electrostatic potential on molecular surface, ∑Vs- and σ＋^2, together with the number of chlorine （ NCl ） and the energy of the highest occupied molecular orbital （EHOMO） can be well used to express the quantitative structure-retention relationship （QSRR） of PCNs. Predictive capability of the model has been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient （Rcv^2） of 0.997, and further compared with the results from similar researches published recently. Furthermore, when splitting the 62 PCNs into training and validation sets in the ratio of 2：1, a similar treatment yields an equation of almost equal statistical quality and very similar regression coefficients, validating the robustness and prediction capability of our model. The QSRR model established may provide a new powerful method for predicting chromatographic properties of polychlorinated naphthalenes.

Responses of Seed Yield and Economic Benefit of Winter Oilseed Rape(Brassica napus L.) to Different NPK Ratio and Dose

Field experiments were conducted during 2008-2010 to investigate the effects of NPK fertilization on seed yield and economic benefit of a new hybrid cultivar of winter oilseed rape(Brassica napus L.)- Xiangzayou763,and to determine the optimum NPK ratio and dose in Hunan,China.The results showed that NPK ratio(1:0.50:0.50) with 180 kg/hm2 N,90 kg/hm^2 P_2O_5 and 90 kg/hm^2 K_2O was the optimum combination for the highest seed yield(2 231.13 kg/hm2) and economic benefit(9 816.97 Yuan/hm^2),of which 1 641.23 Yuan/hm^2 being set for fertilizer investment(VCR=4.11).Besides,the effects of N,P and K fertilizers on seed yield and oil production of winter oilseed rape were not identical.N had the greatest effect on plant growth of winter oilseed rape,followed by P and K.Total leaf number,green leaf number,leaf length and width,rhizome diameter,branch number,dry weight per plant and other agronomic characters in high N treatments were higher than those in low N treatments.By correlation and path analysis of yield components,the contribution rate to seed yield was found:effective silique number per plant>seed number per silique>1 000-seed weight.

Cardiac energy metabolism disorder mediated by energy substrate imbalance and mitochondrial damage upon tebuconazole exposure

Tebuconazole exposure has been described as an increasing hazard to human health.An increasing number of recent studies have shown a positive association between tebuconazole exposure and cardiovascular disease risk,which is characterized by the reduction of adenosine triphosphate(ATP)synthesis.However,researches on the damage of tebuconazole exposure to energy metabolism and the related molecular mechanisms are limited.In the present study,male C57BL/6 mice were treated with tebuconazole at different low concentrations for 4 weeks.The results indicated that tebuconazole could accumulate in the heart and further induce the decrease of ATP content in the mouse heart.Importantly,tebuconazole induced an obvious shift in substrate utilization of fatty acid and glucose by disrupting their corresponding transporters(GLUT1,GLUT4,CD36,FABP3 and FATP1)expression,and significantly repressed the expression of mitochondrial biogenesis(Gabpa and Tfam)and oxidative phosphorylation(CS,Ndufa4,Sdhb,Cox5a and Atp5b)related genes in a dosedependent manner.Further investigation revealed that these alterations were related to the IRS1/AKT and PPARγ/RXRαpathways.These findings contribute to a better understanding of triazole fungicide-induced cardiovascular disease by revealing the key indicators associated with this phenomenon.

控释肥料对早熟油菜产量、养分吸收和肥料利用率的影响（英文）

目的:氮(N)、磷(P)和钾(K)是作物生长发育所必需的营养元素。然而,过度地投入会导致田间低效的利用率,造成大量养分损失,影响土壤、水和大气的质量,以及人类健康和生物多样性。因此,本实验研究控释肥料(CRF)是否可以替代可溶性肥料(SF),有效地增加作物产量,提高肥料利用率,减少田间养分损失。创新点:连续2年(2011~2013年)在中国南方红黄壤地区开展田间试验,研究控释肥料对早熟油菜(湘杂油1613)的产量、生长、养分吸收和肥料利用率的影响。可更好地解决稻-稻-油生产过程中的季节矛盾,简化油菜生产模式,增加农民收入,并确保国家粮油安全。方法:设置SF和等量CRF五个施用量处理,即SF1/CRF1(3750 kg/hm^2)、SF2/CRF2(3000 kg/hm^2)、SF3/CRF3(2250 kg/hm^2)、SF4/CRF4(1500 kg/hm^2)和SF5/CRF5(750 kg/hm^2),以及不施肥处理(CK)。结论:CRF处理油菜产量较SF处理两年平均提高14.51%,其中CRF4和SF3处理获得最大产量(2066.97和1844.50 kg/hm^2),其次是CRF3处理(1929.97 kg/hm^2)和SF4处理(1839.40 kg/hm^2)。此外,CRF4处理利润最高(人民币7126.4元每公顷),与SF4处理相比,其油菜产量增加12.37%和单位肥料施用量下降11.01%。较SF处理,CRF处理显著增加油菜分支数、角果数和干物质重量(P<0.05)。单株角果数是油菜产量构成的主要因素。随着肥料施用量的增加,N、P和K吸收量先增加后下降,而N、P和K利用率均降低。同时,CRF处理的N、P、K吸收量和N、P、K利用率显著高于SF处理的结果(P<0.05)。CRF处理N素累积量和N素利用率较SF处理平均提高13.66%和9.74个百分点。总之,CRF一次性基施显著促进油菜的生长发育,通过提供后期生长阶段足够的养分,最终减少了土壤中的养分残余和增加了植株的养分积累,提高了肥料利用率。