Dc GA20ox2 and DcGA2ox1 alter endogenous gibberellin contents and adjust lignin accumulation in carrot

Gibberellins(GAs)are a class of plant hormones that can affect plant growth and development.GA-oxidases are rate-limiting enzymes,which play a direct role in GA accumulation in plants.However,the roles of GA-oxidase on carrot(Daucus carota L.)taproot development are still unclear.In this study,two GA-oxidase genes,DcGA20ox2 and DcGA2ox1,were identified in carrot.Transgenic carrot plants were obtained by using Agrobacterium-mediated genetic transformation method.The results showed that overexpression of DcGA20ox2 significantly promoted the accumulation of active GAs in carrot,increased plant height,generated more branches,and enhanced xylem development.Overexpression of DcGA2ox1 significantly reduced the total contents of active GAs compared with the control group,resulting in a dwarf phenotype and markedly increased lignin content of the transgenic carrot.The expression profiling showed that the genes of GA metabolic pathway responded to the negative feedback regulation mechanism.At the same time,the expression of most genes in lignin biosynthesis and polymerization process was up-regulated,corresponding to the massive accumulation of lignin.These findings indicated that DcGA20ox2 and DcGA2ox1affected carrot growth and development by regulating the levels of endogenous GAs.The results from current work might shed light on further studies aimed to regulate lignification in carrot and other crops.

Overexpression of PbrGA2ox1 enhances pear drought tolerance through the regulation of GA_(3)-inhibited reactive oxygen species detoxification and abscisic acid signaling

Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberellins(GAs)play crucial roles in plant growth,development,and responses to drought stress.Previous studies have shown significant reductions of GA levels in plants under drought stress;however,our understanding of the intrinsic regulation mechanisms of GA-mediated drought stress in pear remains very limited.Here,we show that drought stress can impair the accumulation of bioactive GAs(BGAs),and subsequently identified PbrGA2ox1 as a chloroplast-localized GA deactivation gene.This gene was significantly induced by drought stress and abscisic acid(ABA)treatment,but was suppressed by GA_(3)treatment.PbrGA2ox1-overexpressing transgenic tobacco plants(Nicotiana benthamiana)exhibited enhanced tolerance to dehydration and drought stresses,whereas knock-down of PbrGA2ox1 in pear(Pyrus betulaefolia)by virus-induced gene silencing led to elevated drought sensitivity.Transgenic plants were hypersensitive to ABA,and had a lower BGAs content,enhanced reactive oxygen species(ROS)scavenging ability,and augmented ABA accumulation and signaling under drought stress compared to wild-type plants.However,the opposite effects were observed with PbrGA2ox1 silencing in pear.Moreover,exogenous GA_(3)treatment aggravated the ROS toxic effect and restrained ABA synthesis and signaling,resulting in the compromised drought tolerance of pear.In summary,our results shed light on the mechanism by which BGAs are eliminated in pear leaves under drought stress,providing further insights into the mechanism regulating the effects of GA on the drought tolerance of plants.

Exogenous Application of Abscisic Acid or Gibberellin Acid Has Different Effects on Starch Granule Size Distribution in Grains of Wheat

Granule size distribution of wheat starch is an important characteristic that can affect its chemical composition and the functionality of wheat products. Two high-yield winter wheat cultivars were used to evaluate the effects of the application of exogenous ABA or GA during the reproductive phase of the initial grain filling on starch granule size distribution and starch components in grains at maturity. The results indicated that a bimodal curve was found in the volume and surface area distribution of grain starch granules, and a unimodal curve was observed for the number distribution under all treatments. The exogenous ABA resulted in a significant increase in the proportions （both by volume and by surface area） of B-type （〈9.9 Ixm in diameter） starch granules, with a reduction in those of A-type （〉9.9 ~tm） starch granules, while, the exogenous GA3 led to converse effects on size distribution of those starch granules. The exogenous ABA also increased starch, amylose and amylopectin contents at maturity but significantly reduced the ratio of amylose to amylopectin. Application of GA3 significantly reduced starch content, amylopectin content but increased the ratio of amylose to amylopectin. The ratio of amylose to amylopectin showed a significant and negative relationship with the volume proportion of granules 〈9.9 μm, but was positively related to the volume proportion of granules 22.8-42.8 μm.

The heading-date gene Ghd7 inhibits seed germination by modulating the balance between abscisic acid and gibberellins

Seed dormancy of cultivated rice was largely weakened during the progress of domestication.Correct timing and uniformity of seed germination are important for rapid seedling establishment and highyield production.In the present study,we found that the heading-date gene Ghd7 acted as a negative regulator of germination.A mutant of ghd7 showed low sensitivity to exogenous ABA treatment during seed germination.Further investigation revealed reduced accumulation of ABA in mature ghd7 seeds as a consequence of dampened expression of OsNCED genes.Moreover,elevated GA_(3) level was detected in seeds of ghd7 mutant during imbibition course,which was attributed to the induction of genes responsible for the synthesis pathways of bioactive GAs.Thus,Ghd7 inhibits seed germination by increasing the ABA/GA_(3) ratio.Besides revealing pleiotropic effects of Ghd7,our results indicate its role in linking seed germination to growth-phase transition in rice,which would enrich the theoretical basis for future breeding practices.

Study on the removal of NO_x from simulated flue gas using acidic NaClO_2 solution

The study on the removal of NOx from simulated flue gas has been carded out in a lab-scale bubbling reactor using acidic solutions of sodium chlorite. Experiments were performed at various pH values and inlet NO concentrations in the absence or presence of SO2 gas at 45℃. The effect of SO2 on NO oxidation and NO2 absorption was critically examined. The oxidative ability of sodium chlorite was investigated at different pH values and it was found to be a better oxidant at a pH less than 4. In acidic medium, sodium chlorite decomposed into C102 gas, which is believed to participate in NO oxidation as well as in NO2 absorption. A plausible NOx removal mechanism using acidic sodium chlorite solution has been postulated. A maximum NOx removal efficiency of about 81% has been achieved.

A ca. 2.2Ga Acidic Magmatic Event at the Northern Margin of the Yangtze Craton: Evidence from U-Pb Dating and Hf Isotope Analysis of Zircons from the Kongling Complex

Objective The Yangtze craton collisional orogeny at ca. extensional events at ca. 1 experienced Paleoproterozoic 1.95-2.0 Ga and post-orogenic 85 Ga related to amalgamation of the Columbia （Nuna） supercontinent （Zhao and Cawood, 2012）. A ca. 2.15 Ga suprasubduction zone ophiolitic melange was recongized in the Archean- Paleoproterozoic Kongling Complex of the northern Yangtze craton （Han et al., 2017）. However, the tectonic evolution in early Paleoproterozoic from 2.4 Ga to 2.2 Ga remains unclear. We report here the presence of a suite of Paleoproterozoic （2.2 Ga） granites in the Huangling dome, northern Yangtze craton, which may provide important insights into crustal growth processes in the craton prior to the assembly of Columbia.

Analyzing solubility of acid gas and light alkanes in triethylene glycol

Physical solvents such as ethylene glycol （EG）, diethylene glycol （DEG）, and triethylene glycol （TEG） are commonly used in wet gas dehydration processes with TEG being the most popular due to ease of regeneration and low solvent losses. Unfortunately, TEG absorbs significantly more hydrocarbons and acid gases than EG or DEG. Quantifying this amount of absorption is therefore critical in order to minimize hydrocarbon losses or to optimize hydrocarbon recovery depending on the objective of the process. In this article, a new correlation that fully covers the operating ranges of TEG dehydration units is developed in order to determine the solubility of light alkanes and acid gases in TEG solvent. The influence of several parameters on hydrocarbon and acid gas solubility including temperature, pressure, and solvent content is also examined.

Gas Chromatography Analysis of Resin and Fatty Acids from Laboratory Generated Bleach Plant Effluents

Laboratory generated spent bleached liquor from the chlorination, caustic extraction stage of mixed wood kraft pulp processing has been analyzed both qualitatively and quantitatively for various resin & fatty acids by using GC. A number of resin acids, saturated and unsaturated fatty acids, chloro fatty and resin acid have been detected and their concentrations are estimated. The results are compared with results on different agriculture residue/hardwood pulps, which were reported earlier. The concentrations of various compounds detected have also been compared with their reported LC50 values.

Seed Germination in Tomato: A Focus on Interaction between Phytochromes and Gibberellins or Abscisic Acid

Separately, it is well-documented that phytochromes (phys), gibberellin (GA) and abscisic acid (ABA) strongly control the seed germination in tomato. However, we hipothesized that phys interact with GA or ABA during this response. Thus, we make an analysis of seed germination of ABA deficient (sit), GA constitutive response (pro), phytochrome deficient (au) mutants as well as, specially, au sit and au pro double mutants of tomato?incubated in the dark or light conditions during 120 h [12 h intervals (i)]. Compared to au, which severely?reduced percentage germination (Gi%) and pro, which did not alter Gi%, au pro showed in the light enhanced Gi% and germination speed index (GSI) besides the reduced average germination time (AGT). Moreover, in the dark, germination of au pro was similar to pro. These results indicate that the mechanisms by which GA modulate germination in tomato are light dependent through the phy signaling, whereas intermediary values of Gi%, GSI and AGT in dark and light of au sit compared to au and sit single mutants indicate an additive effect of the au and sit mutations, suggesting that ABA and phy may act through the parallel signaling pathway.

Adsorption of Naphthenic Acids from Dewaxed Vacuum Gas Oil by Activated Clay: Kinetics, Equilibrium and Thermodynamic Studies

This work was mainly concentrated on the removal of naphthenic acids(NAs) from dewaxed vacuum gas oil(VGO) by adsorption using a commercial grade activated clay(AC) adsorption during lube base oil refining. The NAs in dewaxed VGO cut-4 were identified by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS). The AC sample from a refinery was characterized by XRD, BET, TG/DTA, and SEM. A series of experiments were carried out to investigate the performance of NAs adsorption by AC using a batch adsorption technique, in which some key experimental parameters such as temperature, contact time, initial concentration of NA in oil sample as well as the dosage of adsorbent were investigated. Equilibrium isotherms were analyzed using the Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich(D-R) adsorption models. The pseudo-first order, the pseudo-second order, and intraparticle diffusion models were employed to describe the kinetics data. The results revealed that the D-R isotherm provided a better fit to the experimental data than other isotherms, and the adsorption kinetics followed the pseudo-first order kinetic equation. The thermodynamic data indicated that the adsorption process was feasible and spontaneous as an endothermic process. The results could provide a clear understanding of the NAs adsorption by AC during lube base oil processing at refineries.

基于GA-BP神经网络的鲅鱼鲜味肽美拉德反应增鲜研究

【目的】建立遗传算法(GA)与多层前馈神经网络算法(BP神经网络)预测模型,优化鲅鱼副产物鲜味肽美拉德反应过程中的关键参数,为研制鲅鱼调味品及促进鲅鱼资源的绿色加工利用提供参考依据。【方法】以鲅鱼副产物为原料,加入适量D-木糖进行美拉德反应增鲜,采用单因素试验分别考察D-木糖质量浓度、初始pH、反应时间和反应温度对反应产物褐变值(A420 nm)、最终pH和感官评分的影响;在此基础上,建立以D-木糖质量浓度、初始pH、反应温度和反应时间为输入层,以产物的感官评分为输出层的BP神经网络,并利用GA进行寻优;通过氨基酸分析,对比美拉德反应前后氨基酸变化,分析鲜味的变化情况。【结果】单因素试验结果显示,当D-木糖质量浓度为40 g/L、初始pH为6.0、反应时间为90 min、反应温度为120℃时,鲅鱼副产物鲜味肽A420 nm、最终pH和感官评分达最佳。使用69组样本对GA-BP神经网络模型进行7次迭代后,均方误差(MSE)达最小值0.005287,样本相关系数(R)最大值为0.98317,得到准确度最优的拟合模型;使用18组样本对模型进行验证分析后发现,18组样本的R=0.98787,表明建立的GA-BP神经网络模型可很好地预测不同工艺参数下美拉德反应结果;使用该模型得到最佳工艺条件:D-木糖质量浓度36 g/L、初始pH 5.4、反应时间70 min、反应温度119℃,在此条件下,鲜味肽的感官评分为9.58分,与预测值(9.62分)接近。鲅鱼副产物鲜味肽的水解氨基酸经美拉德反应后,鲜味氨基酸含量增加,特别是谷氨酸含量从56.21 mg/g增至70.39 mg/g,提高25.23%;甜味氨基酸含量从103.98 mg/g增至155.64 mg/g,提高49.68%;而游离氨基酸在美拉德反应后大部分降低,损失率为27.76%。【结论】基于GA-BP神经网络模型优化的美拉德反应增鲜工艺,可明显提升鲅鱼副产物鲜味肽的鲜味特征。

Sweet Cherry (<i>Prunus avium</i>L.) Fruit Drop Reduction by Plant Growth Regulators (Naphthalene Acetic Acid NAA and Gibberellic Acid GA₃)

This study was conducted during 2019/2020 on sweet cherry trees (Prunus Avium L.) (Bing and Hardy Giant) cultivar planted at Sergaya-Al_Zabadani area of Rural Damascus, to reduce fruit drop of sweet cherry. The experiment included 4 foliar applications: T1: control, T2: GA3 (100 ppm), T3: NAA (20 ppm), T4: (100 ppm GA3 + 20 ppm NAA). Fruit set and fruit drop percentage, fruiting factor, and yield were recorded. The results showed that treatment with (100 ppm GA3 + 20 ppm NAA) recorded higher fruit set percentage (73.81% and 75.62%), and fruiting factor (48.38% and 50.04%) respectively; In addition to fruit yield (40.19 and 41.21 kg/tree) for both cultivars, compared to the control (9.13, 6.60 kg/tree). Therefore, it can be concluded that GA3 + NAA treatment reduced Sweet cherry fruit drop better than other treatments, where fruit drop percentage didn’t exceed (63.11% and 62.01%) in both cultivars (Bing and Hardy Giant) respectively, compared to the control (80.92% and 80.64%).

A comparison of methods used to determine the oleic/linoleic acid ratio in cultivated peanut (Arachis hypogaea L.)

There is an increasing demand in the peanut industry for high oleic peanuts and also for the incorporation of the high oleate trait into newly released varieties. Early generation screening of breeding lines for high oleic acid content greatly increases the efficiency of developing new peanut varieties. The objective of this study was to compare the accuracy of methods used to classify individual peanut seed as high oleic or not high oleic. Results from capillary electrophoresis (CE), two variations of near-infrared reflectance spectroscopy (NIRS), and real-time polymerase chain reaction (RT-PCR) genotyping, were compared with the traditionally accepted reference standard results from gas chromatography (GC). Three hundred and seventy-four (374) seeds, spanning twenty-three (23) genotypes and all four peanut market-types (runner, Spanish, Valencia and Virginia), were individually tested by each method. Percent accuracy levels for rating individual seed as high oleic (H) ranged from 97.4% (NIRS) to 99.5% (CE). All of the methods examined in this study carry only a minor risk for miss-classification (loss of material) and are suitable for use by peanut breeding programs in early generation breeding line screening.

外源GA3和ABA对烤烟内源激素调控效应和常规化学成分的影响

本文从激素和基因水平探究外源激素赤霉素(GA3)和脱落酸(ABA)的作用机理,研究其对烤烟生长发育及产量和质量的影响,为田间施用外源激素提供理论依据。采用大田试验,材料为中烟100(ZY100)和NC71,喷施不同浓度配比的GA3和ABA,测定不同时期烟株的农艺性状、基因表达量、生理特性、内源激素含量及烤后烟叶化学成分。结果表明,与未喷施GA3处理相比,喷施GA3后ZY100株高升高20%,NC71株高升高31%;喷施ABA后ZY100株高降低17%,NC71株高降低10%。喷施GA3后ZY100和NC71内源赤霉素含量分别升高20%和30%;喷施外源GA3后ZY100和NC71烟株内CPS、GA20ox和PSY的基因表达量均上调,GA2ox基因表达量下调。喷施GA3提高了ZY100和NC71烟株体内叶绿素以及可溶性蛋白的含量,降低了丙二醛含量,提高了烤后烟叶总糖含量、钾含量、钾氯比,降低了烟碱含量和氯含量,显著提高了烤烟的经济性状。

Impact of Oil and Gas Activities on Acidity of Rain and Surface Water of Niger Delta, Nigeria: An Environmental and Public Health Review

Acidic aerosols resulting from gas flaring and refinery operations in the Niger Delta are a serious environmental and public health concern. Several thousand tons of flue gas components (dust particles, SOx, CO and NOx) are released into the atmosphere by flaring billions of cubic meters of natural gas, refining and volatilizing the spilt oil. Heat wave is generated by flaring travels several meters away from flare points, destroying crops, farm lands, exotic species that are hunters delight while causing extinction of fragile soil flora and fuana. The occurrence of acid rain in the region implies that the natural receptors of the area are the final recipient of land and atmospheric pollutants. In effect, the water needs and public health of the populace are greatly impeded. Nitric and sulphuric acids are regarded as the sole contributors of nitrate and sulphate in precipitation influenced by combusted hydrocarbons: fine nitrate aerosols that dissolve in rain water are conversion products of NO2 that arise from flaring, power plants and motor vehicles. Scientific evidence has shown that rain water and surface water quality in the Niger Delta can accentuate the poor health burden, and may be perpetuated through generations unborn. Diagnostic health risk assessment has revealed that drinking nitrate contaminated water may be associated with spontaneous miscarriage, ectopic pregnancy, adult malignant lymphomas, soft tissues sarcomas, cancers and lesions with added health burden associated with heavy metals and other ions. All these pose public health emergency and may significantly entrench health risk for generations to come. Therefore, this manuscript is intended to close certain gaps that were not covered by toxicological information and available data on environmental and food contamination and human internal exposure: it will serve as a continuous reminder and a useful guide to public health policy makers, workers and community based physicians.

Assessment of Trans Fatty Acid Content in Widely Consumed Snacks by Gas Chromatography in a Developing Country

Trans fatty acids have adverse effects on health, so knowledge of their contents in foods would enable people to make informed food choices. TFA levels when not available in food composition tables make it difficult to estimate dietary intake. With the aim to analyze and identify the actual amount of trans fatty acid present in selected Indian fast food items, triplicate samples of six commonly consumed snacks as well as the oil used for preparing the same were collected from three different places. The separation of fatty acid was done using gas chromatography. Trans fatty acid isomers of oleic acid, linoleic acid and linolenic acid were identified in all food items. The predominant trans fatty acid present in all the food items was elaidic acid (18:1t9). The total trans fatty acids in different food items ranged from almost negligible to as high as 14.58 g/100g food. Different amount of TFA was found in same food category sourced from different outlets which is a challenge in making regulations aimed at TFA reduction so as to decrease health risk.

Determination of Perillic Acid in Bioconversion Supernatants by Gas Chromatography

Perillic acid can be obtained from microbial oxidation of the exocyclic methyl group of limonene. Due to the pharmacological potential of such a metabolite, the biotransformation processes leading to its synthesis have been approached in recent studies. A robust analytical method is needed to assess the performance of such studies. An analytical method was developed and validated to determine perillic acid in the supernatants of a yeast-induced bioconversion of limonene, involving gas chromatography (GC) and an acid-induced precipitation during the sample preparation. GC analysis was performed using a column with polyethylene glycol as stationary phase (HP-Innowax) which resulted in higher loads and better peak shape. The sample preparation involved the supernatant initial filtration and precipitation with 0.6 M HCl followed by centrifugation and dissolution in ethyl acetate. GC analysis conditions were oven from 50°C to 250°C at 20°C·min-1, and then held 5 min (total runtime 15 min). Injector was set at 280°C, and detector at 300°C. Helium was the carrier gas at 1 ml·min-1. Injections of 1.0 μl were at the split ratio 25:1. The method was validated: Linearity with R2 of 0.9992, Accuracy of 98.3% in the range 190 - 950 μg·ml-1;Limit of detection of 10.4 μg·ml-1;Repeatability of 2.1% RSD. Thus, a complete methodology to determine perillic acid in a bioconversion supernatant was developed and validated. This overall approach may be useful for bioconversions of monoterpenes by other microorganisms that metabolize limonene.

SA和GA_(3)浸种对盐胁迫下青蒿种子萌发及幼苗生长的影响

以青蒿种子和幼苗为试材,对盐胁迫下青蒿种子分别进行不同浓度水杨酸(salicylic acid,SA)和赤霉素(gibberellin,GA_(3))浸种处理,研究浸种后青蒿种子的萌发指标、幼苗的生长和生理生化指标的变化,以期为提高青蒿耐盐性,缓解盐胁迫对青蒿的伤害提供参考依据。结果表明:150 mmol·L^(-1)盐胁迫显著抑制了青蒿种子萌发和幼苗生长。盐胁迫条件下,随着SA和GA_(3)浸种浓度的增加,青蒿种子的萌发指标、幼苗的生长指标和生理生化指标总体呈先升后降的趋势,以SA浓度为0.3 mmol·L^(-1)和GA_(3)浓度为400μmol·L^(-1)的浸种缓解盐胁迫效果最佳。综上,在高盐胁迫条件下,适宜浓度的外源SA和GA_(3)浸种处理能显著提高青蒿种子萌发率,提高种子的耐盐性,减轻盐对幼苗生长的抑制作用。

ABA与GA对水稻籽粒灌浆的调控

灌浆初期籽粒中ABA(脱落酸)含量(ng g^(-1)FW)和ABA与GA(赤霉素)的比值,强势粒高于弱势粒,籽粒充实度好的组合高于籽粒充实度差的组合.开花后2天,喷施外源ABA,籽粒中ABA含量和ABA/GA增大,喷施外源GA后籽粒中GA含量增加,ABA/GA减小.低浓度(15mg/L)ABA处理后,灌浆初期籽粒中ADPG焦磷酸酶和淀粉合成酶活性及淀粉含量增加,可溶性糖含量减少;弱势粒灌浆速率增大,至达最大灌浆速率的时间提前,物质运转率、结实率和粒重提高;高浓度(30mg/L)性糖含量减少;弱势粒灌浆速率增大,到达最大灌浆速率的时间提前,物质运转率、结实率和粒重提高;高浓度(30 m吕/L)ABA和高、低浓度(20和 40 mg/L儿A处理后结果则相反.表明在灌浆初期适当提高籽粒中 ABA含量和ABA与GA比值,有促进水稻籽粒灌浆的作用.

抗冷与不抗冷水稻在低温期间叶片ABA与GA_1水平变化的差异

采用抗冷性强的东乡野生稻（东野）和对低温敏感的６２２５两个籼稻品种。发现稻苗的抗冷性与低温期间内源脱落酸（ＡＢＡ）含量上升及赤霉素（ＧＡ１）含量下降均有密切关系。东野的抗冷性比６２２５强，可能是因为其内源ＡＢＡ、ＧＡ１水平对低温的响应比６２２５迅速，东野的ＡＢＡ／ＧＡ１比值在低温２４ｈ时就已达到最大值。