Dormancy of Amaranthus retroflexus L. Seeds and Physiological Response Seedlings to Acifluorfen Sodium

Amaranthus retroflexus L. is a serious and widespread malignant weed in soybean fields in Heilongjiang Province. Exploring the dormancy characteristics of A. retroflexus L. seeds and the physiological response of its seedlings to acifluorfen sodium can provide a basis for further researches on its resistance mechanism. Using newly harvested and stored A. retroflexus L. seeds for one year as experimental materials, the effects of different concentrations of HCl, NaOH, water temperature, gibberellic acid(GA) and polyethylene glycol(PEG) on the dormancy and germination of A. retroflexus L. seeds were studied. The sensitivity of A. retroflexus L.to acifluorfen sodium was determined using bioassay. The effects on leaf chlorophyll content and target enzyme activity were studied at a normal dosage of 360 g a.i. hm^(-2) and a doubling dosage of 720 g a.i. hm^(-2) of acifluorfen sodium. Newly harvested seeds exhibiting dormancy were soaked in water of various temperatures and in different concentrations of NaOH and HCl, which were ineffective in breaking the seed dormancy. GA could break seed dormancy, and the highest seed germination rate reached 93.33% when they were soaked at 3 000 mg·L^(-1) for 72 h and 4 000 mg·L^(-1) for 48 h. The drought stress was simulated with a 15%-25% polyethylene glycol solution, which had no significant effect on the seed germination rate. The GR_(50) value of acifluorfen sodium for A. retroflexus L. was 705.7 g a.i. hm^(-2), which was 1.96 times the recommended dose in the field. After the application of different doses of acifluorfen sodium, the chlorophyll content of A. retroflexus L. reached its minimum value 3 days after treatment(DAT), and then gradually increased. The activity of the target enzyme protoporphyrinogen oxidase(PPO) reached the highest value at 7 DAT under different dosages, and gradually returned to normal levels thereafter. Soaking with gibberellin was an effective method to break seed dormancy. A. retroflexus L. seeds had certain drought resistance during the germination process. A. retroflexus L. was not sensitive to acifluorfen sodium and acifluorfen sodium ether, and could not effectively inhibit the PPO activity, indicating that A. retroflexus L. had target resistance to acifluorfen sodium.

Herbicidal activity and biochemical characteristics of the botanical drupacine against Amaranthus retroflexus L.

Botanical herbicide has been a hot topic in the research and development of novel pesticides. The herbicidal activity and biochemical characteristics of the botanical compound drupacine were studied by evaluating its effects on seed germination, seedling growth, morphological and physiological characteristics of Amaranthus retroflexus. Drupacine inhibited seed germination and seedling growth, and had a median inhibition concentration(IC50) value of 38.99 mg L-1against A. retroflexus root. The α-amylase activity and soluble sugar content in treated plants were significantly lower than that of the control. The expression of α-amylase gene was dosage-dependently inhibited compared to the untreated control. This suggested that inhibition of α-amylase activity was a mode of action on seed germination. The root hairs were significantly decreased and part of the root cap fell off after treatment with drupacine. The ultrastructure observation showed that cell damage of root tips increased with the treatment time. Drupacine also increased the relative conductivity and malondialdehyde(MDA) content. Peroxidase(POD), catalase(CAT), and superoxide dismutase(SOD) activities were significantly enhanced in the treatment compared to the control. These findings indicated that the physiological and biochemical reaction changes leading to morphological and membrane injuries were the main effects of drupacine on the inhibition of seedling growth. Drupacine can be developed as a botanical herbicide.

EDTA和柠檬酸对反枝苋(Amaranthus retroflexus L.)Cu迁移富集影响研究

为明确反枝苋(Amaranthus retroflexus L.)对Cu的富集能力及EDTA与柠檬酸(CA)对Cu迁移的影响,采用盆栽试验,在0、100、200、400、800 mg·kg-1 Cu处理质量分数及2.5 mmol·kg-1 EDTA和柠檬酸施加条件下,测定了根际土、非根际土Cu不同形态含量及反枝苋组织Cu富集特征。结果表明:Cu处理质量分数小于400 mg·kg-1时,重金属Cu组织富集特征为根>叶>茎,Cu处理质量分数在400 mg·kg-1时,富集特征为根>茎>叶,Cu各处理组BCF与TF均小于1,不具备Cu超富集植物特征;EDTA、柠檬酸均可促进反枝苋对土壤中Cu的富集,并强化Cu由根系向地上部分的转移。EDTA的促进作用远高于柠檬酸,在Cu 800 mg·kg-1,施EDTA处理组反枝苋地上部分Cu可达3 513 mg·kg-1。施加EDTA可增加根际土全Cu含量,显著减少根际土中Fe-Mn态Cu含量,增加Exch态,促使Fe-Mn态向Exch态的转化;柠檬酸处理的根际土中则以Fe-Mn态向Carb态转化为主。由此可见,在EDTA强化修复下,反枝苋富集Cu的能力明显增加,而根际土中Cu全量的增加,是Cu-EDTA迁移活性极大增加与反枝苋防御性Cu阻隔共同作用的结果。

An ABAGE-Like Metabolite of Botrytis cinerea Isolate BC4 Inhibited the Growth of Hypocotyls and Roots of Amaranthus retroflexus Seedlings

A metabolite, which had an inhibitory effect on plant growth, was isolated from cultural filtrate of Botrytis cinerea isolate BC4 by column chromatography on silica gel and preparative HPLC. Its structure was determined from HPLC-ESI MS, GC, IR, ^1H NMR and ^13C NMR spectral data, as well as chemical hydrolysis. The results showed that this metabolite was quite similar to abscisic acid-β-D-glucopyranosyl ester（ABAGE） in structure. The inhibitory effect of the ABAGE-like metabolite on plant growth was investigated using a weed Amaranthus retroflexus L. as a bioassay material. The results showed that it inhibited hypocotyls and roots growth of A. retroflexus （Amaranthus retroflexus L.） seedlings when its concentration was over 0.5 μM. The concentrations for 50% inhibition of hypocotyls and roots growth of A. retroflexus seedlings were 2.8 and 1.4 μM, respectively.

苋菜LAC基因家族成员全基因组鉴定与表达分析

漆酶作为生物体内一类重要的铜蓝蛋白,起着调控植物生长、抵抗逆境的作用。基于苋菜基因组及转录组数据,对苋菜漆酶基因家族成员(AtrLAC)进行鉴定,利用在线软件进行生物信息学分析,并根据转录组TPM值进行家族成员相对表达分析。结果表明,在苋菜基因组中共筛选获得19个LAC基因;AtrLAC家族蛋白长度范围在118~1191 aa之间,分子量为13.05~135.10 kD;理论等电点范围为6.49~9.85,多数为亲水呈碱性稳定的蛋白;亚细胞定位预测显示多数在细胞膜外或质膜上。系统进化树分析将苋菜19个LAC成员和拟南芥的17个LAC成员聚为6个类群。TPM值分析显示,AtrLACs在不同处理下的表达量存在差异,其中AtrLAC7基因可能在甜菜色素合成、响应激素调控及光条件下发挥重要作用。

不同积累型苋菜(Amaranthus mangostanus L.)镉吸收转运特征差异性研究

【目的】比较高积累型苋菜品种Tianxingmi与低积累型苋菜品种Zibeixian在Cd胁迫下Cd吸收转运特征差异性,揭示苋菜品种Tianxingmi高积累镉的机理。【方法】采用水培试验,添加代谢抑制剂来研究两品种苋菜根系吸收Cd的主要途径。分别在30μmol/L Cd Cl2处理4 h、8 h、16 h、1 d和2 d采样测定,采用非损伤微测技术(Non-invasive micro-test technique,NMT),进行植物活体动态测试,调查、测量两品种苋菜根系Cd^(2+)离子流特征,比较了两品种对代谢抑制剂的反应。【结果】在30μmol/L Cd Cl2处理1 d后,Tianxingmi生物量达到最大值5.90 g/plant,是Zibeixian生物量的二倍;Tianxingmi根、茎和叶中Cd浓度分别为609、254和62.3mg/kg,分别是Zibeixian的1.4倍、1.9倍和1.6倍,地上部和全株的Cd累积量分别高达602.0、1308μg/plant;Tianxingmi富集系数(BCF)与转运系数(TF)分别为Zibeixian的2.1倍和1.5倍,这些结果两品种均表现出显著性差异(P<0.05)。NMT技术测定两品种根系Cd^(2+)离子流,通过扫描位点测定发现,距根尖0~300μm范围内两品种苋菜根系Cd^(2+)内流最强且差别最大,并在此做定点位点测定,发现Tianxingmi根系Cd^(2+)内流是Zibeixian根系Cd^(2+)内流的3.75倍,说明了两品种的富集特征与NMT结果一致。添加代谢抑制剂处理显著降低了高积累型Tianxingmi各器官中的Cd浓度,富集系数(BCF)与转运系数(TF),以及根系Cd^(2+)内流(P<0.05),主动吸收特征明显,而对低积累型Zibeixian的相关生理指标影响不大。【结论】两苋菜品种Cd吸收转运特征均表现出显著性差异。Tianxingmi具有更强的Cd吸收和向地上部转运与累积能力,并且根系对Cd的吸收与转运是主动需能的过程,共质体途径在Cd进入Tianxingmi根系并向地上部运输的过程中起着主要作用。

Extraction and Purification Process Optimization and Antioxidant Activity in vitro of Flavonoids in Amaranthus caudatus L.

[Objectives]To explore the optimal extraction and purification process of the flavonoids in Amaranthus caudatus L.and to study the antioxidant activity in vitro of the flavonoids in A.caudatus.[Methods]Taking A.caudatus as the raw material,flavonoids were extracted by alcohol extraction method,and AB-8 macroporous adsorption resin was selected for purification.The hydroxyl radical scavenging ability,DPPH radical scavenging ability,and O^2-radical scavenging ability were used as evaluation indicators,to explore the antioxidant activity in vitro of the flavonoids in A.caudatus.[Results]The optimal extraction process conditions of flavonoids in A.caudatus are:liquid-to-material ratio 40:1,extraction temperature 60℃,ethanol concentration 60%,ultrasonic power 320 W,extraction time 50 min.Under these conditions,the extraction yield of flavonoids in A.caudatus is(1.35±0.01)%.The optimal purification process conditions of flavonoids in A.caudatus are 2.5 g AB-8 macroporous adsorption resin,sample volume 5 mL,mass concentration of adsorption solution 1.60 mg/mL,pH value of adsorption solution 3.0,sample flow rate 3 BV/h,ethanol concentration in desorption process is 70%and the desorption flow rate is 3 BV/h.Under these conditions,the recovery rate reaches 88.35%±0.68%.[Conclusions]A.caudatus has a high content of flavonoids and has excellent free radical scavenging ability in vitro.This study is intended to provide important technical support for the research of flavonoid activity of A.caudatus and the development of functional products.

反枝苋对氟磺胺草醚的抗性机制代谢组学研究

二苯醚类除草剂氟磺胺草醚是防除大豆田杂草反枝苋Amaranthus retroflexus L.的主要除草剂,但黑龙江省大豆田反枝苋对氟磺胺草醚的抗性越来越强,严重影响大豆产量。目前尚无关于反枝苋对氟磺胺草醚抗性机制的代谢组学研究。本研究基于未处理(CK)以及氟磺胺草醚处理后反枝苋敏感种群(SY)、抗性种群(RY)的叶组织的代谢谱,进行主成分分析(PCA)和正交偏最小二乘法判别分析(OPLS-DA),发现RY组代谢分子表型更贴近于CK组。京都基因与基因组百科全书(KEGG)富集分析和拓扑分析结果发现,氟磺胺草醚的主要作用通路有3条,分别是biosynthesis of amino acids (氨基酸的生物合成)、arginine biosynthesis (精氨酸生物合成)和2-oxocarboxylic acid metabolism (2-氧代羧酸代谢)。CK vs RY和SY vs RY有1条共有的差异通路——degradation of flavonoids (类黄酮的降解),因此,类黄酮的降解可能是RY组抗性的特异性通路。通过支持向量机(SVM)分析进一步发现,4-hydroxy-2-oxoglutaric acid (4-羟基2-氧化戊二酸)、citrulline (瓜氨酸)和L-ornithine (L-鸟氨酸)是氟磺胺草醚处理后反枝苋产生抗药性的关键代谢物。

反枝苋对氟磺胺草醚的抗性水平及分子机制

[目的]本研究旨在明确黑龙江省大豆田反枝苋(Amaranthus retroflexus L.)种群对氟磺胺草醚的抗药性水平,并研究其产生抗性及多抗性的分子机制。[方法]利用琼脂法快速测定采自黑龙江省嫩江县的3个反枝苋种群对氟磺胺草醚的抗性水平。通过盆栽法筛选出抗氟磺胺草醚/噻吩磺隆的反枝苋植株,并进行原卟啉原氧化酶(protoporphyrinogen Ⅸ oxidase, PPO)和乙酰乳酸合酶(acetolactate synthase, ALS)的靶标基因测序。[结果]相比于敏感种群,黑龙江省3个种群对氟磺胺草醚的相对抗性倍数(resistance index, RI)分别为83.6、83.8和93.4;位于反枝苋PPO2高度保守区域编码128位氨基酸的核苷酸由AGG突变为GGG,导致精氨酸被替换为甘氨酸(Arg-128-Gly)。3个抗氟磺胺草醚的反枝苋种群均对ALS抑制剂类除草剂产生多抗性。对als基因测序后发现,与敏感种群相比,各抗性种群10个单株的ALS保守区域均发生多个不同位点(Ala-205-Val、Asp-376-Glu、Trp-574-Leu和Ser-653-Thr)及组合的氨基酸取代方式,各种群突变位点和杂合度多样。[结论]PPO2的Arg-128-Gly氨基酸取代可能是黑龙江3个反枝苋种群对氟磺胺草醚产生抗性的主要原因,3个种群同时对ALS抑制剂类除草剂存在靶标位点突变导致的多抗性。

大豆田反枝苋对除草剂多抗性及靶标抗性机理研究

黑龙江省大豆田反枝苋Amaranthus retroflexus对ALS、PPO抑制剂类除草剂产生了严重抗性,为明确化学防除失败的反枝苋对咪唑乙烟酸、氟磺胺草醚的抗性机理,采用整株生物测定法测定了反枝苋抗性及敏感种群对除草剂的敏感性,克隆了抗性和敏感种群的ALS、PPO基因(质体型PPX1及线粒体型PPX2),查找突变位点,将突变基因转入拟南芥Arabidopsis thaliana验证其功能,明确抗性机理。结果显示:反枝苋抗性种群对咪唑乙烟酸、氟磺胺草醚抗性倍数分别为55.29倍和17.51倍,抗性植株ALS存在Ala205Val或Ser653Asn突变,PPX2存在Arg128Gly突变。将抗性种群的PPX2转入拟南芥,可导致拟南芥对氟磺胺草醚产生高水平抗性(10.3倍)。综上,东北大豆田反枝苋对咪唑乙烟酸、氟磺胺草醚产生了高水平多抗性,ALS、PPO基因突变是导致此类抗性的主要原因之一。

An ABAGS-Like Metabolite of Botrytis cinerea Isolate BC4 and Its Inhibitory Activity to Seed Germination of Weeds

Aimed at finding out natural compounds to kill weeds, a plant pathogenic fungus, Botrytis cinerea isolate BC4, was chosen as a source. A significantly polar metabolite, which was different in chromatographic behavior from ABAGE-like metabolite, was isolated from cultural filtrate of the fungus by column chromatography on silica gel, preparative LC, TLC and HPLC. The structure of the metabolite was determined by HPLC-ESI MS, g.l.c, IR, ^1H NMR and hydrolysis. The results showed that this metabolite was quite similar with ABAGS. The bioassay showed the metabolite had inhibition to seed germination of both broadleaf weeds [Amaranthus retroflerus L. and Chenopodium album L.] and gramineae weeds [Digitaria sanguinalis L. Scop and Echinochloa crusgalii L. Beauv]. It also had inhibitory activity to the seedling growth of broadleaf weeds. The bioassay, using Amaranthus retroflexus L. as an indicator, showed that the lowest concentration of the metabolite to inhibit root＋sprout growth of A. retroflexus was 0.6 μM, and the concentration for 50% inhibition was 1.3μM.

基于DNA条形码鉴别青葙子及其混伪品绿穗苋种子

目的:基于DNA条形码对青葙子、绿穗苋种子进行鉴定。方法:基于ITS2、psbA-trnH、matK、rbcL常用DNA条形码的通用引物对样品进行扩增、测序,并从NCBI数据库下载ITS2、psbA-trnH、matK、rbcL碱基序列。利用MEGA 11.0软件构建NJ系统发育树、计算遗传距离及比较种间差异,并基于ITS2序列构建二级结构。结果:基于上述序列构建的NJ树均独立聚为一支,其中ITS2的种间遗传距离最大,基于ITS2构建的二级结构具有明显差异。结论:基于DNA条形码ITS2碱基序列及其二级结构可准确鉴别出青葙子及其混伪品绿穗苋种子,psbA-trnH碱基序列可以作为辅助鉴别序列。

反枝苋花粉泛过敏原profilin基因的克隆表达、纯化及免疫学鉴定

目的克隆表达反枝苋花粉中泛变应原肌动蛋白抑制蛋白(profilin),并鉴定其免疫学活性。方法利用RT-PCR结合RACE技术克隆反枝苋花粉泛变应原profilin的全长基因,并进行序列分析。设计带有酶切位点的特异性引物,采用RT-PCR获得整个反枝苋花粉profilin的开放阅读框,将其与p ET28a载体连接并转化大肠杆菌BL21(DE3)进行诱导表达,Ni2+亲和层析柱纯化重组蛋白,采用Western-blot检测其Ig E结合活性。结果 c DNA核苷酸测序表明反枝苋花粉profilin的全长基因由675个碱基组成,开放阅读框为399 bp,编码131个氨基酸。重组反枝苋花粉profilin在大肠杆菌中可溶性表达,进一步经Western-blot检测具有良好的Ig E结合活性。结论成功地克隆和表达了反枝苋花粉profilin,并具有良好的Ig E应答免疫活性。

基于集合模型预测外来植物反枝苋的入侵趋势

反枝苋(Amaranthus retroflexus L.)是一种入侵较早、分布范围广、危害程度严重的全国性分布恶性杂草。为了及时防控反枝苋,阻止或减缓进一步扩散蔓延,亟需明确其在中国的适宜生境及入侵趋势。基于296个分布点和32个环境变量,利用集合物种分布模型分析反枝苋在当前(1970-2000年)的潜在适生区,并预测未来(2021-2040年和2041-2060年)3种气候情景下(SSPs1-2.6、SSPs2-4.5和SSPs5-8.5)的分布格局,综合分析影响反枝苋地理分布的主要环境变量及入侵趋势。结果表明,1)通过3种模型精度评价指标(AUC、KAPPA和TSS),集合模型(EM)模拟和预测的结果最为准确,当前气候条件下反枝苋主要的潜在适生区分布在华北地区、华中地区、华东地区、华南地区、西南地区的东部、西北地区的南部和北部些许地区,分布面积为4.39×10^(6) km^(2)。反枝苋的潜在分布重心位于陕西省延安市宜川县,地理坐标为110.32°E,36.13°N。2)影响反枝苋潜在分布的主要环境变量为年平均温度(Bio1)、土地利用覆盖(LUCC)、海拔(Altitude)和年降水量(Bio12)。3)在2030年和2050年的3种不同气候情景下,随着年份和排放情景的增加,反枝苋的总适生区面积均会增加,并且扩张区的面积远大于收缩区的面积,扩张面积的比率在11.2%-21.4%。反枝苋在未来均有向高纬度地区扩散的趋势,华北地区的东部和东北地区的南部扩散面积最为显著,西北地区的南部和西南地区的东部也在逐渐扩散。该研究结果将有助于对该物种入侵动态的早期预警,为及时采取防控措施阻止其传播扩散提供理论支持。

硒和丛枝菌根真菌处理对苋菜生长及硒积累的影响

【目的】探明丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)在苋菜富硒栽培中的生物效应,综合评价AMF对不同硒形态处理下苋菜生长和硒积累的影响。【方法】采用盆栽试验,分析了土施外源硒和接种AMF对苋菜光合作用、生长状况、苋菜红素以及硒积累的影响。【结果】硒酸钠、亚硒酸钠和L-硒代半胱氨酸处理均降低了苋菜红素含量,但对菌根侵染率和菌根依赖性均无显著影响,同时显著提高了苋菜叶片叶绿素a、b含量、蒸腾速率(T_(r))、气孔导度(G_(s))、净光合速率(P_n)和胞间CO_(2)浓度(C_(i)),其中L-硒代半胱氨酸处理效果最佳,说明外源硒处理对苋菜的生长有一定的正效应。另外,接种AMF对不同硒处理下苋菜的生长也有促进作用,且提高了叶片苋菜红素含量,同时增强了光合能力和根茎叶硒含量的积累。【结论】接种AMF和外源硒处理均能提高苋菜的光合能力和硒积累能力,从而促进苋菜生长和提高苋菜营养品质,两者交互处理可作为提高蔬菜富硒栽培的有效措施。

不同除草配方对大豆田抗性反枝苋防除效果的研究

为探索黑龙江省北部大豆主产区抗性反枝苋最佳防治方法,文章优选4种苗前封闭除草剂及4种苗后茎叶除草剂进行田间防效试验,分析不同药剂组合对反枝苋的防除效果。结果表明,苗前封闭处理,90%乙草胺EC 1800 g a.i./hm^(2)和30%丙炔氟草胺SC 51 g a.i./hm^(2)对反枝苋防效较高,施药45 d后,反枝苋防效为87.79%;苗后茎叶处理,250 g/L氟磺胺草醚AS(科坦见露灵)750 g a.i./hm^(2)+助剂(伴豆一生)2000 m L/hm^(2)对反枝苋的防效较高,且持效期长;苗前封闭结合苗后茎叶处理,90%乙草胺EC 1800 g a.i./hm^(2)+30%丙炔氟草胺SC 51 g a.i./hm^(2)+250 g/L氟磺胺草醚AS 500 g a.i./hm^(2)+480 g/L灭草松AS 1680 g a.i./hm^(2)+助剂(迪增)225 m L/hm^(2)对反枝苋的防效达93%,且持效期长。大豆田抗性反枝苋防控方法中,苗前封闭处理防效显著高于苗后茎叶处理。生产中建议以苗前封闭除草为主,结合苗后化学除草、轮作等措施综合防治反枝苋。

Influence of Adjuvants on the Control of Glyphosate-Resistant Canada Fleabane and Waterhemp in Corn with Tolpyralate

Tolpyralate is a new benzoylpyrazole herbicide for weed management in corn. It is recommended to be co-applied with atrazine along with the adjuvants methylated seed oil concentrate (MSO) plus an ammonium nitrogen fertilizer, such as urea ammonium nitrate (UAN). Two studies were conducted on glyphosate-resistant (GR) Canada fleabane and GR waterhemp to determine if an additional adjuvant is still required when tolpyralate plus atrazine are tankmixed with a commercial glyphosate formulation (Roundup WeatherMAX&reg;) in corn. Trials were conducted over a two-year period (2018-19) on farms in south western Ontario with confirmed GR populations. When co-applied with Roundup WeatherMAX&reg;, the addition of MSO to tolpyralate + atrazine increased control of GR waterhemp 9%;however, there was no increase in GR Canada fleabane control from the addition of additional adjuvants. At 8 WAA, all treatments provided > 91% and > 84% control of GR waterhemp and GR Canada fleabane, respectively. This study concludes that the addition of Roundup WeatherMAX&reg;to tolpyralate plus atrazine improves the control of GR waterhemp and GR Canada fleabane in corn.

Canopy Hyperspectral Reflectance of Redroot Pigweed versus Okra and Super Okra Leaf Cotton

Redroot pigweed (Amaranthus retroflexus L.) is a nuisance weed that affects cotton (Gossypium hirsutum L.) growth and yield worldwide. Being able to distinguish redroot pigweed from cotton would help producers and crop consultants better implement strategies used to suppress and control it. Hyperspectral reflectance properties of weed and crop canopies have been used to differentiate between them. Currently, no information is available on the application of hyperspectral data to distinguish redroot pigweed from cotton with different leaf shapes. Positive results will further support the exploration of remote sensing technology for distinguishing redroot pigweed from cotton. The objectives were to compare canopy hyperspectral reflectance of redroot pigweed to canopy hyperspectral reflectance of okra and super okra leaf cotton and to identify regions of the spectrum in which differences exist in their reflectance properties. Hyperspectral reflectance measurements of redroot pigweed and cotton were obtained with a spectroradimeter on May 6 and June 27, 2019. Plants grown in a greenhouse were used for this study. One-hundred and sixty-two 10-nm bands (400 - 2350 nm spectral range) were evaluated with analysis of variance (p ≤ 0.05) and Dunnett’s test (p ≤ 0.05) to determine the wavebands that were useful for separating redroot pigweed from okra leaf and super okra leaf cotton. The following bands were consistent in distinguishing redroot pigweed and okra leaf cotton on both dates: 420 nm, 510 - 650 nm, 690 - 740 nm, and 2000 - 2010 nm;whereas, 400 - 500 nm, 1480 - 1780 nm, and 1990 - 2350 nm were identified for both dates for separating redroot pigweed from super okra leaf cotton. Commercial imaging systems used on ground-based or airborne platforms can be easily tuned into the spectral bands listed in this study, thus providing managers with a tool to use for identifying redroot pigweed in cotton production systems.

生物炭有机肥部分替代化肥对苋菜生长、产量、品质和氮素利用率的影响

为探究化肥减施潜力和生物炭有机肥增效作用,缓解因化肥过量施用导致的蔬菜品质下降和肥料利用率降低等问题,以苋菜为试材,设6个施肥处理:不施肥(CK1)、100%常规施肥(CK2)、85%常规施肥+2250 kg·hm^(-2)生物炭有机肥(T1)、85%常规施肥+4500 kg·hm^(-2)生物炭有机肥(T2)、70%常规施肥+4500 kg·hm^(-2)生物炭有机肥(T3)、70%常规施肥+2250 kg·hm^(-2)生物炭有机肥(T4),对比分析各处理苋菜生长、产量、品质、氮肥吸收及利用的差异。结果表明,与CK1相比,施肥不同程度促进苋菜植株生长,增加苋菜根茎叶氮素积累量,苋菜产量提高5.83%~22.67%。与CK2相比,生物炭有机肥部分替代化肥显著增加苋菜的生物量,提升可溶性糖、可溶性蛋白和维生素C含量,降低硝酸盐和有机酸含量;其中,T1和T2苋菜产量分别提高7.28%和11.87%,T2氮肥吸收利用率和氮肥农学利用率分别提升16.74%、21.48 kg·kg^(-1)。综上,T2为最优处理,可促进苋菜生长,提高苋菜产量和氮素利用率,改善品质,是实现肥料高效利用、减肥增效的良好施肥模式。

红苋菜总黄酮超声波辅助提取工艺优化及其抗氧化、抑菌活性

该文以红苋菜为原料,75%乙醇为提取溶剂,利用超声波法优化红苋菜总黄酮的提取工艺,并对其抗氧化活性及抑菌机制进行探究。结果表明:优化的红苋菜总黄酮提取工艺参数分别为料液比1∶40(g/mL)、提取时间2.0 h、提取温度70℃,在此条件下获得的总黄酮提取量为1.498 mg/g。红苋菜总黄酮清除DPPH自由基的IC_(50)值为(38.5±0.6)μg/mL,当红苋菜总黄酮质量浓度为80.00 μg/mL时,对Fe^(3+)的还原能力与阳性对照抗坏血酸接近,红苋菜总黄酮对金黄色葡萄球菌的抑制效果明显,最小抑菌浓度为40.00 mg/mL。随着红苋菜总黄酮质量浓度的增加,细菌培养液中电导率增大,DNA及RNA大分子物质浓度上升,说明红苋菜具有良好的抗氧化活性和抑菌活性。