Effect of water quality indices on phytoplankton of a sluggish tidal creek in Lagos, Nigeria

The phytoplankton of a tidal creek in Lagos was investigated for six months (September 1998-February 1999). The physico-chemical environment was essentially neutral (pH 7.00-7.30), relatively more transparent (> 0.23 m), expressed higher conductivity (> 0.10 mS cm(-1)), higher chloride values (> 23.48 mg L(-1)), lower nitrate content (< 0.70 mg L(-1)), lower sulphate values (< 0.45 mg L(-1)) and phosphate values (< 0.12 mg L(-1)) in the dry months. In the wet months, September to November 1998, conductivity (< 0.16 mS cm(-1)), transparency (< 0.80 m), salinity (< 0.04%), dissolved oxygen (< 24.00 mg L(-1)), chloride (< 24.21 mg L(-1)) and phosphate (< 0.21 mg L(-1)) were recorded. The phytoplankton was dominated by diatoms (48 pennate forms and 23 centric forms). The other algal groups comprised six blue- green algae and six green algae. Species richness (d) was high in stations nearer the Lagos lagoon for the six sampling periods. Shannon-Weaver index (H1) was lowest in November 1998 and highest in October 1998 and February 1999 while evenness of species J was low (< 0.71) throughout the period. Higher phytoplankton biomass was recorded in the dry months than wet months.     

甘蔗花粉离体萌发研究

为筛选适宜栽培种甘蔗花粉离体萌发的培养基配方,建立有效的离体萌发体系,以糖用甘蔗主栽品种ROC22花粉为材料,通过单因素试验探索满足甘蔗花粉离体萌发的基本条件,然后利用L₁₆(4 ⁵)正交试验,寻求甘蔗花粉离体萌发的最适宜培养基配方,在此基础上进一步探讨不同温度对甘蔗花粉萌发的影响。在单因素试验中,培养基以刚好凝固时为最佳。蔗糖、硼酸和硝酸钙在一定范围内对甘蔗花粉萌发起促进作用,超过一定浓度则起抑制作用。硫酸镁作用不稳定,硝酸钾影响较小。正交试验中,蔗糖对甘蔗花粉离体萌发率和花粉管生长速率影响最大,呈显著水平,硼酸次之,硫酸镁影响最小。花粉萌发的适宜温度为30 ℃,萌发率和花粉管长度分别为89.83%和143.03 μm。200 g/L蔗糖+400 mg/L硼酸+100 mg/L硝酸钙+400 mg/L硫酸镁+1 g/L琼脂,在30 ℃下培养花粉萌发率最高,花粉管生长状态良好,这种方法可快速有效鉴定不同甘蔗花粉活力差异。     

The effects of rates of application and sources of nitrogen on nitrate concentration in oat forage

A field experiment was conducted during the winter seasons of 1972–73 and 1973–74 to study the effects of rates of application (0, 100, 200 kg ha^?1) and sources of nitrogen (ammonium sulphate, calcium ammonium nitrate, urea, sulphur-coated urea and sulpha-thiazole-treated urea) on nitrate-N concentration in oat (Avena sativa L.) forage. N application increased the nitrate-N concentration, the effects being more marked when the rate was increased from 100 to 200 kg ha^?1 than when it was raised from 0 to 100 kg ha^?1. The highest nitrate-N concentration in the dry matter (> 0·16%) was obtained when calcium ammonium nitrate was applied at 200 kg ha^?1 N. Sulphur-coated urea gave the lowest nitrate-N concentration. In one year treatment of urea with sulphathiazole reduced nitrate-N concentration in oats forage.     

Nutritional and toxic factors in selected wild edible plants

Nutritional (ascorbic acid, dehydroascorbic acid and carotenes); antinutritional and toxic components (oxalic acid, nitrate and erucic acid) were determined in sixteen popular species of wild edible plants which are collected for human consumption in southeast Spain. Ascorbic+dehydroascorbic acids contents were very high in several species, especially in Chenopodium album L. (155 mg/100 g). Carotenoid content ranged from 4.2 mg/100 g (Stellaria media Villars) to 15.4 mg/100 g (Amaranthus viridis L.). A range of values was found for oxalic acid from absence to 1100 mg/100 g of plant material. Nitrate contents ranged from 47 mg/100 g ( Salicornia europaea L.) to 597 mg/100 g (Amaranthus viridis L.). Low amounts of erucic acid were found in the Cruciferae family (Sisymbrium irio L. 1.73%; Cardaria draba L. 1.23%) and Plantago major L. 3.45%.     

6-BA和AgNO3对芥菜型油菜下胚轴芽再生的影响

以芥菜型油菜品种Brown mustard的下胚轴为外植体,接种于不同配比6-苄基腺嘌呤（6-BA）和硝酸银（AgNO3）组合的分化培养基中,研究6-BA和AgNO3对芥菜型油菜下胚轴芽再生的影响。结果表明分化培养基中含3 mg/L 6-BA＋5 mg/L AgNO3时出芽率最高,出芽率达到58.33%,芽丛数平均为1.73。     

Potential nephrotoxicity in African mud catfish (Clarias gariepinus) following exposure to compost derived humic acid

Influence of compost-derived Humic Acid (HA) on nephrotoxicity in juvenile African mud catfish (Clarias gariepinus) was evaluated in static water culture. Fish samples were exposed to different HA concentrations (0, 100, 250, 500 and 1000 mg L(-1)) for 45 days at 5 samples per aquarium. Renal function was assessed spectrophotometrically via levels of serum albumin, measured using bromocresol green, creatinine by Jaffe method and urea by Nesslerization method. Results revealed that the mean value of albumin or urea in the exposed group (1), at each HA concentration, was lower than the value found in the control group (II). Creatinine was relatively higher in I relative to II. Significant (p < 0.05) variations for I and II were obtained at 250 to 1000 mgHA L(-1) for the three biomarkers. Relative to increasing HA concentration, decreasing albumin (0.84 to 0.43 g dL(-1): r = -0.114; p > 0.10), urea (5.21 to 1.95 mg dL(-1); r = -0.586; p > 0.10) and increasing creatinine (0.20 to 1.53 mg dL(-1): r = +0.704; p > 0.10) were recorded; r is correlation coefficient. Changes in urea were not predictive of nephrotic syndrome but alterations in albumin and creatinine revealed induced nephrotoxicity, especially at elevated HA concentrations (above 100 mg L(-1)). Overall, the effect of humic acid was dose-dependent. Further studies at various humic acid concentrations, especially below 100 mg L(-1), are required to establish the actual nephrotoxic dose.     

稀土铈诱导玉米根尖细胞hsp70 mRNA表达研究

采用逆转录聚合酶链式反应(RT-PCR),以总RNA作为模板两步法扩增hsp70。设置阳性(热应激)和阴性(蒸馏水培养)对照组,以actin为内参,研究硝酸铈[Ce(NO3)3]胁迫(浓度为1、4、16、64、256mg/L)下玉米根尖细胞hsp70 mRNA表达量的变化。结果表明,Ce(NO3)3各处理组的hsp70 mRNA的表达量高于阴性对照组,1～64mg/L处理组hsp70 mRNA的表达量低于阳性对照组,256mg/L处理组hsp70 mRNA的表达量高于阳性对照组,说明Ce(NO3)3可诱导玉米根尖细胞中hsp70 mRNA的表达。     

水莲石斛的组织培养与快速繁殖

以水莲石斛（Dendrobium Hibiki）幼嫩假鳞茎为外植体进行组织培养和快速繁殖研究。结果表明:利用75%乙醇结合0.1% HgCl₂,以及适宜程序进行外植体消毒,成功率达92.50%;诱导腋芽的最适培养基为改良MS添加3.0 mg/L 6-BA和0.5 mg/L NAA,腋芽诱导率为91.90%;丛生芽增殖最适培养基为MS培养基添加5.0 mg/L 6-BA和0.5 mg/L NAA,平均增殖系数为2.77;生根壮苗最适培养基为1/2 MS+0.5 mg/L IBA+1.5 g/L活性炭+30 g/L蔗糖+100 g/L土豆泥,生根率100%,生根效果最好;体积比1∶1的植金石与椰壳混合基质适合于移栽,移栽成活率为95.56%。     

播娘蒿高频率再生植株因素的研究

以播娘蒿子叶、子叶柄和下胚轴为外植体，研究不同外植体、激素组合以及硝酸银对播娘蒿再生频率的影响。结果表明：外植体、激素以及硝酸银的影响都非常显著；最佳外植体为下胚轴；最佳激素组合为6－BA（2．0mg/L) NAA(0.5mg/L);附加AgNO3(1.7mg/L)可使下胚轴再生频率提高63．42％。诱导生根的最佳培养基为1／2MS＋NAA（0．5mg/L) IBA(0.5mg/L)。     

吸附茶多酚树脂的筛选

通过对４种离子交换树脂和１６种吸附树脂对茶多酚的交换或吸附及解吸性能的研究表明，９２─２和９２─３吸附树脂对茶多酚有较强的吸附能力和较好解吸性能，优于ＡｍｂｅｒｌｉｔｅＸＡＤ─７和日本ＨＰ─２１。经这两种树脂静态吸附后，其提取物的茶多酚含量均可达６０％左右（对照仅为２６．６％，用日本《茶分析法》修改法测定结果）。表明这两种树脂适于从茶叶中制取高纯度茶多酚制品的工艺要求。     

离子色谱法测定茶叶中的硝酸盐和亚硝酸盐

建立了离子色谱法测定茶叶中硝酸盐和亚硝酸盐的分析方法。样品经超声提取后,用PVPP吸附和固相萃取柱净化的方法进行前处理,经高容量阴离子交换柱分离,抑制型电导检测器检测。结果表明,样品中硝酸盐和亚硝酸盐的回收率范围分别为88.6%~107.5%和89.3%~101.2%。相对标准偏差（RSD）为1.67%和1.13%。离子色谱法测定硝酸根和亚硝酸根具有操作简便、测定快捷、准确性高的优点。     

The influence of different hormone concentration and combination on callus induction and regeneration of Rauwolfia serpentina L. Benth

The influence of media composition on callus induction and subsequent regeneration of Rauwolfia serpentina L. Benth has been studied. High frequency (96.43%) callus induction was obtained when nodal segments from in vitro raised shoots were cultured on MS medium supplemented with 0.5 mg L(-1) BA and 2.0 mg L(-1) NAA. The callus differentiated into adventitious shoots when it was subcultured on MS medium supplemented with 2.0 mg L(-1) BA with 0.2 mg L(-1) NAA. Regenerated shoots were best rooted on half-strength MS medium with 1.0 mg L(-1) each of IBA and IAA.     

不同种植制度对农村饮用水硝酸盐污染的监测研究

为了解辽宁省农村饮用水硝酸盐污染现状,2005～2008年连续四年七次采集粮食、蔬菜主产区农户井水样品1 307个,利用TU-1810 DASPC紫外可见光光度计测定了硝酸盐含量。结果表明,粮食、蔬菜主产区农村饮用水硝酸盐含量平均值为18.96 mg/L,大于20 mg/L的样品占32.08%。保护地蔬菜产区农户饮用水硝酸盐含量平均值为21.26 mg/L,个别的蔬菜种植户地下水硝酸盐含量达到396.67 mg/L。水稻产区农村饮用水硝酸盐含量平均值为20.62 mg/L,玉米产区农户饮用水硝酸盐含量为17.8 mg/L。     

大规模悬浮培养茶叶细胞合成茶氨酸培养基组成优化研究

婺源绿茶嫩叶用MS培养基（加IBA 2βmg/L,6-BA 4βmg/L,盐酸乙胺25βmmol/L）进行茶叶愈伤组织悬浮培养,采用正交试验设计研究了培养基不同组成条件对茶叶细胞大规模悬浮培养过程中细胞生长与茶氨酸合成的影响。结果显示,整个培养周期中,细胞收获量和茶氨酸积累量峰值出现时间为培养的第19~22βd;在NH₄⁺/NO₃^- 1.0/60.0βmmol/L、K⁺ 100.0βmmol/L、Mg²⁺ 3.0βmmol/L、H₂PO₄^- 3.0βmmol/L、蔗糖30.0βg/L、水解酪蛋白2.0βg/L条件下,茶叶细胞生长量和茶氨酸积累量分别可达到16.33βg/100βml培养液和3.357βg/100βml培养液;提高培养基中水解酪蛋白浓度可使细胞对数生长期和稳定期得到延长,并有利于茶氨酸积累;H₂PO₄^-浓度主要影响细胞生长速率和茶氨酸积累速率的同步性,低H₂PO₄^-浓度环境中茶氨酸积累速率峰值滞后于细胞增长速率峰值,高H₂PO₄^-浓度环境中早于细胞生长速率峰值出现时间;K⁺ 和蔗糖对细胞生长的影响均不明显;Mg²⁺对细胞生长产生明显的影响;NH₄⁺/NO₃^-对茶氨酸合成具有非常显著的影响。从生产效率考虑,培养周期以19~22βd为宜。     

茶树农杆菌转化系统和基因枪转化系统的优化

在用农杆菌浸染前,将茶树外植体预培养在含有PVP(polyvinylpyrrolidone,16g/L)的预培养基上2-3d可提高转化频率。优化后的茶树基因枪转化体系,即制弹程序:60 mg/1ml钨粉悬浮液10 l中加入1.6 l质粒DNA(1 g/l),再分别加入0.1 mol/L的亚精胺4 l,2.5 mol/L 的CaCl2 15 l,最后定容至48 l;每次轰击上样量为8-10 l。基因枪转化后抗性筛选2个月,抗性愈伤组织存活率为5.0%~12.1%。     

不同类型茶园土壤N2O排放速率及其影响因素

对不同生产力(高、中、低产)和种植年限(10、45、100 a)的茶园及与其相邻林地土壤N2O的排放速率进行了田间原位测定,并探究其与土壤pH、有机碳、总氮、水溶性有机碳氮、微生物生物量碳氮(MBN)、铵态氮和硝态氮等土壤理化性质的关系.结果表明,不同类型茶园间的土壤理化性质有显著差异,且各土壤理化性质之间有一定相关性...     

番木瓜优质组培苗生产体系的建立

用含有100mg/LVc＋1mg/LAgNO;+20mg/LPVP液体处理成龄番木瓜（CricappayaL）侧芽,再用70%酒精浸泡50s、0.15%升汞消毒5min,经消毒的外植体接种于MS+KT0.5mg/L+NAA0.2mg/L+GA31.0mg/L＋30g/L蔗糖+7g/L琼脂（pH=5.7）,26~28℃,每日光照培养12h,光照强度为15001x,连续培养20d;外植体经初始培养后,继代接种于MS＋BA0.5mg/L+NAA0.1 mg/L+GA,1.0mg/L+蔗糖30gL＋琼脂7g/L（pH=5.7）,26~28℃,每日光照培养16h,光照强度为2000Ix,连续培养40d,繁殖系数达3~5倍;继代芽接种MS+BA0.2mg/L+KT0.3mg/L+NAA0.Img/L+NAA0.1 mg/L+GA;1.0 mg/L+ADS40mg/L＋蔗糖30g/L＋琼脂7g/L（pH=5.7）,26~28℃,每日光照培养16h,光照强度为20001x,连续培养20d进行壮苗培养,经壮苗培养芽接种于MS+KT0.1~0.2mg/L+ NAA0.05~0.1mg/L+ IBA0.2-0.3mg/L+蔗糖20~30gL+琼脂6.5g/L（pH=5.6）,26~28℃,每日光照培养12h,光照强度为1500kx,连续培养 15~20d 进行催根培养,生根率达85%以上。生根苗经2~3d的自然光炼苗后,移栽于沙土∶椰糠∶菜园土质量比为1∶1∶1 混和的基质中,移苗后1周内,每天喷施浓度为200～400mg/L的IBA,移栽成活率达80%以上。笔者就目前番木瓜组培快繁中的问题作了系统的研究,建立了一套适合番木瓜优质种苗生产的技术体系。     

Decolorization of aqueous caprolactam solution by anion-exchange resins

Caprolactam is the most important raw material for making Nylon 6 fibers and its quality directly determines the quality of Nylon. So it is necessary to study the techniques and methods to remove the colorful impurities from caprolactam. In this paper, the decolorization of caprolactam aqueous solution by anion exchange resins was studied and the decoloring abilities of five commercial resins were investigated. The regeneration of the resins was also studied, too. This study shows that the resin AMTX202 have excellent decoloring ability in the column experiment and that the decoloring efficiency is correlated with the volume of resins packed and is slightly affected by the flow rate and regenerating times. The fact that the resins can be regenerated and reused without affecting the efficiency of decolorization will decrease the cost of the treatment and operation in the industry. The adsorption of colored compounds with anion exchange resins in the packed columns seems to be technically feasible.     

施氮对杂交狼尾草产量及硝酸盐的影响

采用田间小区试验.研究不同供氮水平对杂交狼尾草产量、硝酸盐含量及烘干率的影响.结果表明,随着施氮水平的提高.杂交狼尾草(Pennisetum americanum×P purpureum)的产量也明显提高,但相同的施氮水平对不同品种的影响差异不显著,单茬最高产量出现在8月份.在N,(300 kg/hm2)水平时,闽牧6号杂交狼尾草(S16)的总产量(15.34 kg/m2)虽然比推广品种杂交狼尾草(S1)总产量(14.84 kg/m2)高,但差异不显著;硝酸盐含量.也随着氮素水平的提高而提高.试验期内,8月份的硝酸盐含量最低,闽牧6号的硝酸盐含量在相同的施氮水平下均较高,说明硝酸盐更易于在闽牧6号体内积累,但在0～300 kg/hm2氮肥水平下,硝酸盐含量均处在牲畜的安全食用标准内;烘干率不受施氮水平的影响,只与生长量有关,生长量大,则烘干率高.     

贵港报春苣苔的叶片组培与植株再生

以贵港报春苣苔的叶片为外植体,研究不同培养基对其不定芽诱导和增殖、愈伤组织诱导与分化以及生根的影响。结果表明,外植体叶片以纵切为宜,不定芽诱导最适培养基为MS+6-BA 4.0 mg/L+IAA 1.5 mg/L,愈伤组织诱导最适培养基为MS+6-BA3.0～5.0 mg/L+2,4-D0.5～1.0 mg/L,不定芽诱导率以及愈伤组织诱导率均为100.00%;愈伤在MS+KT 1.0 mg/L+NAA 0.2 mg/L+potato 30 g/L+banana 30 g/L+apple 20 g/L+coconut juice 100 mL/L培养基上分化系数达12.64;不定芽在MS+ZT 1.0 mg/L+NAA 0.10 mg/L+potato 30 g/L+banana 30 g/L+apple 20 g/L+coconut juice 100 mL/L培养基的增殖系数为8.55;不定芽在3/4 MS+NAA 0.01～0.05 mg/L+活性炭1.0～3.0 g/L培养基上的生根率为100.00%。综上所述,叶片纵切后能通过不定芽途径以及愈伤组织途径建立贵港报春苣苔的组织培养技术体系,在该体系下不定芽增殖系数高、愈伤分化高,组培苗生根好。