Statistical optimization of adsorption processes for removal of 2,4-dichlorophenol by activated carbon derived from oil palm empty fruit bunches

The adsorption capacity of activated carbon produced from oil palm empty fruit bunches through removal of 2,4-dichlorophenol from aqueous solution was carried out in the laboratory. The activated carbon was produced by thermal activation of activation time with 30 min at 800℃. The adsorption process conditions were determined with the statistical optimization followed by central composite design. A developed polynomial model for operating conditions of adsorption process indicated that the optimum conditions for maximum adsorption of phenolic compound were： agitation rate of 100 r/min, contact time of 8 h, initial adsorbate concentration of 250 mg/L and pH 4. Adsorption isotherms were conducted to evaluate biosorption process. Langmuir isotherm was more favorable （R^2=0.93） for removal of 2,4-dichlorophenol by the activated carbon rather than Freundlich isotherm （R^2=0.88）.     

稀土对沙田柚叶片营养和果实品质与产量的效应

试验结果表明,适量施用稀土可提高沙田柚树体对营养元素的吸收,促进养分平衡,从而可提高沙田柚座果率和产量,而且对柚果还有增糖降酸的效果。因此,适时适量施用稀土对提高沙田柚产量和品质均有积极的意义。     

果树缺铁失绿症矫治方法简述

本文简单评述了果树缺铁失绿症的多种矫治方法及其效果,以供各地在矫治果树失绿症时参考。     

沙田柚系列专用肥对柚果产量和品质的影响

报道了沙田柚产区土壤养分状况、沙田柚营养需求特性和叶片与果实对营养元素吸收的季节性变化模式、沙田柚果实品质指标与各时期树体营养元素含量的相关性,以及磷肥活化剂的使用。分析了沙田柚产量和品质提高的因素。研制出了沙田柚系列专用肥,并探讨了其使用的效果和经济效益。     

Polyclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for screening of paclobutrazol in fruits

Abstract

Paclobutrazol (PBZ) is a plant growth regulator (PGR) widely used in fruit and vegetable cultivation. However, due to the severe toxicity of PBZ, a sub-ppm level maximum residue limit (MRL) was established worldwide. Therefore, it is significant to propose a rapid, sensitive and high throughput screening method for monitoring the PBZ residues in foods. In this study, a simple and sensitive indirect competitive Enzyme-linked immunosorbent assay (icELISA) was established for PBZ detection in fruits basing polyclonal antibody. For both economy and pollution prevention, a microwave-solvent-free method was used to synthesize the PBZ hapten with high efficiency. The detection conditions, such as coating antigen concentration, antibody concentration, organic reagent concentration, ionic strength and pH, were optimized. Under the optimized conditions, this method showed high sensitivity and specificity. The detection range is 1.27-138.23?ng/mL, half-maximum inhibition concentration (IC₅₀) is 13.26?ng/mL, and the IC₂₀ was lower than the reported ELISAs for PBZ. Additionally, this method had high accuracy and precision. The recoveries were ranged from 88.78% to 96.80% in PBZ spiked apple samples with RSD below 4%. All the results showed that the polyclonal antibody based icELISA could be useful for PBZ screening in fruit samples.     

中国羊胡子草、水蜈蚣二属果皮微形态特征的比较

利用扫描电镜对国产莎草科羊胡子草、水蜈蚣二属果皮微形态特征进行了比较观察和描述．根据果皮纹饰的差异,可将二属划分为两个类型：类型Ⅰ,具网状纹饰;类型Ⅱ,具网瘤状复合纹饰．在类型Ⅱ中,根据每一网眼中的瘤状突起数目及是否具小疣状附属物又可分为两个亚型．即网、单瘤亚型和网、复瘤亚型．研究结果表明：羊胡子草、水蜈蚣二属果皮微形态特征具有多样性、复杂性和稳定性等特点,可作为上述二属种间区别的依据．该研究对于探讨莎草科属间亲缘关系和系统发育也有一定意义     

Sorption of chlorophenols onto fruit cuticles and potato periderm

To better understand the interaction mechanisms of plant surfaces with polar organic compounds, sorption of 4-chlorophenol, 2,4- dichlorophenol, and 2,4,6-trichlorophenol by fruit cuticles (i.e., tomato, apple, and pepper), and potato tuber periderm were investigated. The roles of cuticular components (waxes, cutin, cutan and sugar) on sorption of chlorophenols are quantitatively compared. Cutin and waxes govern the sorption capacity of bulk apple cuticle by hydrophobic interactions. Potato periderm with highest sugar content exhibits the lowest sorption capability for the chlorophenols. With the increase of hydrophobicity (i.e., K_ow ) of sorbate, the relative contribution of lipophilic components (wax, cutin and cutan) on total sorption increases, however, the ratios of K_oc to K_ow decreases due to increasing ionization degree of sorbates.     

珠江三角洲冲积平原种植热带果树的土壤条件探讨

以广州市番禺区万顷沙十五涌的土壤为例，探讨珠江三角洲冲积平原种植热带果树的土壤条件。该地土壤位于珠江三角洲冲积平原，是由工人围海造田而成的，有关部门计划在此大面积种植木瓜、杨桃、番石榴等热带果树。通过在种植果树前进行土壤本底调查，摸清土壤养分含量状况，找出土壤存在问题，并结合果树生长的需要，提出土壤利用改良意见。降低地下水位，合理施肥，建立合理的间套作制度，是提高和稳定土壤肥力的基本措施。     

滨海沙滩造林种果后土壤理化性质的变化

在滨海沙滩营造木麻黄防护林，林带老化后进行更新，部分林地改种潮州柑或芒果而成为果园，并于其间套种农作物或牧卓；结果表明，人为耕作活动对土壤的热化起到了明显的促进作用．在造林种果的同时，大量肥料的施入及优质客土改良了土壤，使＞１．０ｍｍ的砂粒比例明显减少，＜０．０１ｍｍ的粉粘粒及土壤养分含量明显增加，其中沙草地、防护林及果园，０—４０ｃｍ土壤粉粘粒含量分别为５６．４ｇ／ｋｇ、５９．６ｇ／ｋｇ和１０８．９ｇ／ｋｇ，土壤有机质为０．７１ｇ／ｋｇ、２．０２ｇ／ｋｇ和４．１１ｇ／ｋｇ；土壤氮素含量随有机质提高而提高，柑园速效磷和钾含量是沙草地的３７倍和３．５倍，然而防护林的种植对土壤速效磷和钾的影响却不明显；由于雨水淋洗，土壤盐分减少；又由于酸性化学肥料的大量施入，土壤ｐＨ值由８．３下降为５．３．果园的营建，明显改善了土壤的肥力状况及其保水保肥性能，提高了沙滩地的利用价值及生态经济效益．     

Napropamide Residues in Runoff and Infiltration Water from Pepper Production

Abstract

A field study was conducted on a Lowell silty loam soil of 2.7% organic matter at the Kentucky State University Research Farm, Franklin County, Kentucky. Eighteen universal soil loss equation (USLE) standard plots (22 × 3.7 m each) were established on a 10% slope. Three soil management practices were used: (i) class-A biosolids (sewage sludge), (ii) yard waste compost, each mixed with native soil at a rate of 50 ton acre^?1 on a dry-weight basis, and (iii) a no-mulch (NM) treatment (rototilled bare soil), used for comparison purposes. Devrinol 50-DF “napropamide” [N,N-diethyl-2-(1-naphthyloxy) propionamide]was applied as a preemergent herbicide, incorporated into the soil surface, and the plots were planted with 60-day-old sweet bell pepper seedlings. Napropamide residues one hour following spraying averaged 0.8, 0.4, and 0.3 μ g g^{? 1} dry soil in sewage sludge, yard waste compost, and no-mulch treatments, respectively. Surface runoff water, runoff sediment, and napropamide residues in runoff were significantly reduced by the compost and biosolid treatments. Yard waste compost treatments increased water infiltration and napropamide residues in the vadose zone compared to sewage sludge and NM treatments. Total pepper yields from yard waste compost amended soils (9187 lbs acre^?1) was significantly higher (P < 0.05) than yield from either the soil amended with class-A biosolids (6984 lbs acre^?1) or the no-mulch soil (7162 lbs acre ^?1).