Contribution of flavonoids to the antioxidant properties of common and tartary buckwheat

The objective of this study was to characterize the flavonoid compounds found in the different grain parts of common and tartary buckwheat, and to determine the contribution of these flavonoids to the antioxidant properties of buckwheat. Eight flavonoid compounds were quantified and their antioxidant activity determined by FRAP, DPPH, and ABTS assays. Of the flavonoid compounds identified rutin was the most abundant, particularly in tartary buckwheat, in which it comprised approximately 90% of total flavonoid content. Flavan-3-ols were detected in common but not tartary buckwheat, and quercetin was detected only in tartary buckwheat. Flavonoid content—in particular, levels of rutin, orientin, and/or epicatechin gallate—was found to influence the total antioxidant activity of buckwheat. Results from this study indicate that antioxidant activity is not only closely associated with flavonoid content, but that different flavonoids contribute differently to the total antioxidant activity of common and tartary buckwheat.     

施用碱稳定污泥污水土壤经γ-辐照后土壤溶液中Cu和Zn

Soil samples collected from several acid soils in Guangdong, Fujian, Zhejiang and Anhui provinces of the southern China were employed to characterize the chemical species of aluminumions in the soils. The proportion of monomeric inorganic Al to total Al in soil solution was in the range of 19% to 70%, that of monomeric organic Al (Al-OM) to total Al ranged from 7.7% to 69%, and that of the acid-soluble Al to total Al was generally smaller and was lower than 20% in most of the acid soils studied. The Al-OM concentration in soil solution was positively correlated with the content of dissolved organic carbon (DOC) and also affected by the concentration of Al³⁺. The complexes of aluminum with fluoride (Al-F) were the predominant forms of inorganic Al, and the proportion of Al-F complexes to total inorganic Al increased with pH. Under strongly acid condition, Al³⁺ was also a major form of inorganic Al, and the proportion of Al³⁺ to total inorganic Al decreased with increasing pH. The proportions of Al-OH and Al-SO₄ complexes to total inorganic Al were small and were not larger than 10% in the most acid soils. The concentration of inorganic Al in solution depended largely on pH and the concentration of total F in soil solution. The concentrat ions of Al-OM, Al³⁺, Al-F and Al-OH complexes in topsoil were higher than those in subsoil and decreased with the increase in soil depth. The chemical species of aluminumions were influenced by pH. The concentrations of Al-OM, Al³⁺, Al-F complexes and Al-OH complexes decreased with the increase in pH.     

氟铝互作对茶树叶片叶绿素荧光特性的影响

为明确氟和铝对茶树[Camellia sinensis (L.) O. Kuntze]叶片叶绿素荧光特性的影响,采用盆栽沙培的方法,设置不同浓度氟和铝互作处理,采用调制叶绿素荧光仪对其荧光各参数进行分析,结果发现,茶树幼苗在未添加铝的情况下,随着氟浓度的增加,PSⅡ的实际光化学量子效率Y(Ⅱ)、最大荧光（F_m）、最大光化学效率（F_v/F_m）、光化学淬灭系数（qP和qL）降低。最小荧光F_o、非光化学淬灭系数（NPQ和qN）、PSⅡ调节性能量耗散的量子产额Y(NPQ)增加;在低铝水平下,随着氟浓度的增加,F_m、F_v/F_m、Y(Ⅱ)、NPQ和qN等值降低,而qP和qL升高,F_o、Y(NO)和Y(NPQ)值未达显著差异水平;在高铝处理下,随着氟处理浓度的增加,F_o逐渐增加,Y(Ⅱ)、F_v/F_m、qP值下降,Y(NPQ)和NPQ值在低氟时（100βmg·L^-1）显著升高。可见,当受到氟胁迫时,茶树叶片光合效率会降低;添加铝可以减轻对植株造成的伤害,在低铝水平下,对提高叶片光合效率的作用更加明显。     

土壤保水剂对旱地果园土壤保水作用研究

对土壤保水剂（本中心实验室合成）在果园土壤的保水保墒作用及其持续作用的研究结果表明,施用土壤保水剂后,土壤水分含量第一年可提高９％以上,第二年可提高６％以上,第三年可提高４％以上;在约４５ｃｍ土层附近存在一个防止土壤水分下渗的防水层,该处土壤水分含量最高。土壤保水剂的保水作用是通过最大限度利用自然降雨和防止水分下渗及减少土壤水分蒸发来实现的。     

坛紫菜中铝的形态分析及风险性评价

应用化学连续萃取法结合电感耦合等离子体质谱(ICP-MS)法对紫菜中铝的存在形态进行了初步研究,并对紫菜中铝食用安全性进行了评价。所测30份紫菜样品中铝的总含量范围为74.3~1 479 mg/kg,紫菜中铝的形态存在难溶态>有机态>无机态>水溶性游离态的分布规律。约75%的铝以难溶态存在。可溶态的铝主要以有机铝的形态存在,有机铝占总可溶态铝的72%左右。无机铝主要以Al(OH)₃的形态存在,水溶性游离态铝占无机铝的18.5%。通过模拟胃肠消化环境测定紫菜中铝的溶出率,结果表明,模拟胃液可溶出的铝占总铝的1.38%～6.80%,说明大部分铝在人体消化过程中不易溶出,对人体的潜在危害并不大。     

吸附到白浆土中铝的解吸行为研究

为探讨发生铝污染的白浆土中金属铝的解吸特性,采用平衡振荡法,研究铝在白浆土中的解吸行为及不同因素的影响。结果表明:在720min后,白浆土中的铝解吸基本达到平衡;25℃下,土壤有机质含量为42.2g/kg,铝在白浆土中的解吸量仅为吸附量的1.5%;用Langmuir方程可很好地拟合白浆土中铝解吸等温曲线(r=0.985 9**),说明表面均匀单层解吸占主导;热力学参数ΔG0,ΔH0,ΔS0,表明铝的解吸是自发、吸热和熵增加的过程。土壤有机质由42.2g/kg降至27.8g/kg时,白浆土中铝的最大解吸量由25.87mg/kg升至66.11mg/kg,且导致解吸滞后现象的加剧。pH降至3时,铝的解吸量升至226.4mg/kg,是pH在5~7时的8倍以上。随着解吸液中NaCl和Na_2SO_4浓度的增加,铝的解吸量增加。总之,吸附到白浆土中的铝解吸能力较弱,但pH和有机质含量降低,无机盐含量升高,铝的解吸量大幅增加,污染风险急剧上升。     

奶牛场高浓度污水的絮凝预处理效果研究

为了解决奶牛场高浓度污水深度处理难度大的问题,开展了化学絮凝预处理效果研究的试验。选用聚合氯化铝（PAC）和3种离子型的聚丙烯酰胺（PAM）作为絮凝剂,通过对絮凝处理后上清液体积、化学需氧量（COD）和浊度的检测和分析,比较了PAM单独使用以及PAC与PAM复合使用的絮凝效果。结果表明：单独投加PAM比PAC与PAM复合使用的处理效果好,且PAM的离子型对高浓度奶牛场污水处理中COD和浊度的去除率有显著影响。当非离子型聚丙烯酰胺的浓度为1 g/L、投加量为2.5 mL时处理效果最好,出水的COD、氨氮质量浓度和总磷质量浓度分别为（12 892±2 354）mg/L、（462±53）mg/L和（31±3）mg/L,相应的去除率分别可达69.48%±4.10%、13.11%±8.59%和85.05%±1.27%,此时的经济成本为0.05元/m3。采用非离子型聚丙烯酰胺对高浓度奶牛场污水进行预处理是可行的,能够有效降低奶牛场污水中的有机物和悬浮物,减轻后续处理工艺的负荷,研究结果可为奶牛场高浓度污水化学絮凝预处理方法的应用提供科学依据。     

铝胁迫下根系分泌物对栝楼光合特性及耐铝性的影响

以耐铝性较强的安国栝楼和耐铝性较弱的浦江栝楼为对比试验材料,在土培条件下探究300μmol/L和800μmol/L铝胁迫下不同浓度(30,20,10ml/株)根系分泌物对2种栝楼的生长特性、光合特性和抗氧化酶活性的影响。结果表明,经过2个浓度的铝处理后,安国栝楼和浦江栝楼生长均受到一定抑制,生物量、叶绿素a/b含量、叶绿素荧光、CAT、POD、SOD酶活性均呈下降趋势,而MDA、初始荧光(F_0)呈相反的变化趋势,2种栝楼的各指标变化程度和敏感性表现出一定的差异性,表明2种栝楼的耐铝性存在差异。加入适宜浓度的根系分泌物能够促进2种栝楼的生长,提高叶绿素a、b含量以及各个荧光参数值和CAT、POD、SOD等抗氧化酶活性,从而缓解了铝胁迫。较低浓度的根系分泌物可以缓解铝胁迫对栝楼的伤害;浓度过高时,2种栝楼的生长均会受到抑制,20ml/株的根系分泌物对栝楼铝胁迫的缓解作用最佳。因此,今后在红壤地区栝楼的生产种植中,可以进一步开展根系分泌物对栝楼影响机制的研究工作,为栝楼品种的推广与应用奠定基础。     

盐渍海蜇中铝的脱除与质构变化

研究针对海蜇制品中铝残留严重超标的问题,用5种不同试剂对盐渍海蜇进行铝脱除工艺研究,并分析了铝脱除工艺对海蜇质构的影响。试验结果表明:采用剪切法(A/CKB探头)分析海蜇质构,可以更准确更稳定地测得海蜇产品的质构差异;供试的5种试剂中以复合脱铝剂的脱铝效果最佳,在脱除盐渍海蜇中铝的同时,基本保持了海蜇的质构等感官品质,可以较好保持铝脱除后海蜇的品质。     

Aluminum toxicity of synthetic aluminum–humus complexes derived from non-allophanic and allophanic Andosols and its amelioration with allophanic materials

Natural non-allophanic Andosols often show aluminum (Al) toxicity to Al-sensitive plant roots. The significance of Al–humus complexes to Al toxicity has been emphasized. Allophanic Andosols also possess Al–humus complexes, but they rarely show any toxicity. In the present study, using model substances, we tested the toxicity of Al–humus complexes and its amelioration with allophanic materials. We extracted humic substances from the A horizons of a non-allophanic Andosol and an allophanic Andosol using a NaOH solution, and reacted the humic substances and partially neutralized AlCl₃ solution at pH 4. Allophanic material was purified from commercial Kanuma pumice. Plant growth tests were conducted using a medium containing the Al–humus complexes (50 g kg⁻¹), the allophanic material (0, 90, 180 and 360 g kg⁻¹) and perlite. The root growth of barley ( Hordeum vulgare L.) and burdock ( Arctium lappa ) was reduced in the media containing the Al–humus complexes derived from both the non-allophanic and allophanic Andosols when the allophanic material was not added. With the addition of the allophanic materials, particularly in the 360 g kg⁻¹ treatment, the growth of the barley roots was improved markedly. Although the root growth of the burdock tended to improve with allophanic materials, the effect was weaker than that for barley. Monomeric Al in a solution of the medium was not detected (< 0.05 mg L⁻¹) following the addition of 360 g kg⁻¹ of allophanic materials, whereas 0.8–1.7 mg L⁻¹ Al was recorded without the allophanic material.