Decolorization of azo dyes with high salt concentration by salt-tolerant mixed cultures under anaerobic conditions

Because the lack of detailed study of biological decolorization in high salt dye wastewater, it is still difficult to evaluate the biological treatment on high-salinity dye wastewater. The experiments were carried out to study the salt-tolerant bacteria, which is useful in the treatment of high-salinity colored wastewater. Simulated wastewater containing 5-150 g/L salt （NaCI） and 50-2000 mg/L Reactive Brilliant Red K-2BP was treated with three salt-tolerant mixed cultures （CAS, TAS, DSAS）, which were under a gradually acclimated procedure. With the increase of concentrations of salt and dye, the decolorization became low. The abilities of decolorization of dyes wastewater by three mixed cultures （CAS, TAS, DSAS） were studied, CAS and DSAS mixed cultures showed more active for the treatment of high-salinity colored wastewater than TAS mixed cultures. The results suggested that there might be a simple process for the high salt wastewater treatment, which could be incorporated into conventional activated sludge plants.

Generation and analysis of expressed sequence tags from the salt-tolerant eelgrass species, Zostera marina

Zostera marina, a monocotyledonous angiosperm, is one of the most important seagrass species. To inves- tigate the salt-tolerance mechanism and discover salt-tolerant genes in Z. marina, a cDNA library was con- structed. Single-pass sequencing of the 5＇ ends of 4 081 clones yielded 4 002 high quality expressed sequence tags （ESTs）, which were assembled into 241 contigs and 1 673 singletons, representing 1 914 unigenes. The average length of the ESTs was 582 bp, with sizes ranging from 100-1 500 bp. Basic Local Alignment Search Tool （BLASTX） analysis revealed that 1 664 unigenes had significant homology to known genes in the Na- tional Center for Biotechnology Information （NCBI） non-redundant （nr） database （E-value≤5-10）. Among them, the two most abundant genes encoded metallothionein （157 ESTs） and chlorophyll a/b-binding pro- tein （38 ESTs）, accounting for 7.1% and 1.7% of the total ESTs, respectively. Using Kyoto Encyclopedia of Genes and Genomes （KEGG）, 1 462 unigenes were assigned to 1 161 pathways （E-value≤5-10）. A total of 938 unigenes were assigned Gene Ontology （GO） terms based on the GO hierarchy analysis, and InterProScan searches recognized 1 003 InterPro families. Three genes for metallothionein in Z. marina that belonged to Class II was identified. Results of this study will improve understanding of the molecular mechanisms of saline tolerance in Z. marina.

Salt-tolerant mechanism of marine Aspergillus niger cellulase cocktail and improvement of its activity

The cellulase cocktail produced by marine Aspergillus niger exhibits a property of salt-tolerance,which is of great potential in cellulose degradation in high salt environment.In order to explain the mechanism on the salttolerance of the cellulase cocktail produced by marine A.niger,six cellulase components(AnCel6,AnCel7A,AnCel7B,AnEGL,AnBGL1 and AnBGL2)were obtained by directed expression.Studies on their enzymatic properties revealed that oneβ-glucosidase(AnBGL2)and one endoglucanase(AnEGL)exhibited an outstanding salttolerant property,and one cellobiohydrolase(AnCel7B)exhibited a certain salt-tolerant property.Subsequent study revealed that the salt-tolerant An EGL and AnCel7B endowed the cellulase cocktail with stronger salttolerant property,while the salt-tolerant An BGL2 had no positive effect.Moreover,after overexpression of AnCel6,AnCel7A,AnCel7B and AnEGL,the activity of cellulase cocktail increased by 80%,70%,63%and 68%,respectively.However,the activity of cellulase cocktail was not improved after overexpression of AnBGL1 and AnBGL2.After mixed-strain fermentation with cellobiohydrolase recombinants(cel6 a,cel7a and cel7b recombinants)and endoglucanase recombinant(egl recombinant),the the activity of cellulase cocktail increased by 114%,102%and91%,respectively.

Rheological properties of salt-tolerant HPAM solutions with ultrahigh molecular weight

The rheological properties of salt-tolerant partially hydrolyzed polyacrylamide(HPAM)solutions with molecular of 2.5×107 g/mol at different concentrations were measured in steady-state shear flow mode by Haake Rheostress 150 rheometer.Three constitutive equations(Oldroyd four constant model,Guesekus model and FENE-P model) were used for describing the apparent viscosity and first normal stress difference.The apparent viscosity of salt-tolerant HPAM solutions appears a first Newtonian zone when the shear rate is approximately lower than 0.2 s-1.At high shear rate,the HPAM solutions show shear-thinning and elasticity.The results show that the FENE-P model has the best agreement between theoretical and experimental data within the available shear rate range.The material parameters are useful for numerical analysis of polymer solution flow fields.

Response of Salt-Tolerant Rice Varieties to Biocompost Application in Sodic Soil of Eastern Uttar Pradesh

Sodic soils have immense productivity potential, if managed through proper technology interventions. Biocompost is prepared by composting pressmud (a sugar industry byproduct) received from cane juice filtration and spent wash received from distilleries through microbial aerobic decomposition and can be used to reclaim sodic soils. Field experiments were conducted during the wet season of 2011 and 2012 to study the effect of incorporation of biocompost in sodic soil with four treatments: T1—Control, T2—Biocompost at 2 t ha-1, T3—Biocompost at 4 t ha-1 and T4—Biocompost at 6 t ha-1. The two promising salt tolerant rice varieties preferred by farmers, Narendra usar 3 and NDR 359 were used as test crops, which can produce yields ranging between 2-4 t ha-1 in soil having a pH range of 9.2 to 10.5. Among the different doses of biocompost tested, application of biocompost at 6 t ha-1 registered highest yields, enabled by a higher biomass, ear bearing tiller (EBT), and grain fertility in both varieties. Narendra usar 3 was more responsive to treatments even at lower doses of biocompost than NDR 359, but NDR 359 yielded slightly higher than Narendra usar 3 in all treatments. Soil health was also improved evidently on better fertility and low soil pH and EC at harvest. Thus, biocompost can be considered as a commercially viable, environmentally acceptable and practically enforceable option for improving the crop productivity and soil fertility status.

Growth and Transcriptomics Analysis ofMichelia macclurei Dandy Plantlets with Different LED Quality Treatments

Michelia macclurei Dandy is a significant tree species that has extensive cultivation for forestry and horticulture purposes in southern China,owing to its economic and practical importance.Light quality influences plantlet growth and development during tissue culture.However,the growth characteristic and molecular regulation of M.macclurei under different light quality conditions are not well understood yet.In this study,we investigated the morphological,chlorophyll content,and transcriptomic responses of M.macclurei plantlets under different light-emitting diode(LED)qualities,including white,blue,and red light.The results showed that blue light significantly increased plant height(21.29%)and leaf number(18.65%),while red light decreased plant height and leaf number by 7.53%and 16.49%,respectively.In addition,the plantlets’chlorophyll content and etiolation rate were significantly reduced by blue and red light quality compared to white light.Compared to white light,blue light had a negative effect,leading to decreased rooting rate(64.28%),root number(72.72%),and root length(75.86%).Conversely,red light had a positive effect,resulting in increased rooting rate(24.99%),root number(109.58%),and root length(72.72%).Transcriptome analysis identified 54 differentially expressed genes(DEGs)in three groups that consisted of blue light vs.white light(BL-vs-WL),red light vs.white light(RL-vs-WL),and red light vs.blue light(RL-vs-BL).Specifically,21,7,and 41 DEGs were identified in the three groups,respectively.The DEGs found in the RL-vs-WL and BL-vs-WL groups were involved in plant hormone signaling,nitrogen metabolism,and phenylpropanoid biosynthesis pathways,which suggests that M.macclurei plantlets adapt to the changes of light quality via modulating gene expression.Overall,our study provides valuable insights for understanding the molecular and morphological responses of M.macclurei plantlets under different light qualities.

Chemical Composition and Ruminal Digestibility of Ceratoides, a Salt-tolerant Perennial Plant,at Different Years

It has been proposed that salt-tolerant plant could be used as a feed resource for ruminants whereby salt would be removed from salinized land (Asian -Aust. J. Anim. Sci. (2002) 15:998 -1001). Ceratoides arborescens (Losinsk.) Tsien et C. G. Ma is known as a drought-and salt-tolerant plant,a kind of shrubs, growing in semi-arid land of Inner Mongolia. Because the covering effect of the perennial plant as a mulch over the soil might be expected, the optimum covering effect would be obtained after the growth period.The perennial plant produces seeds around summer and end its growth thereafter. Nutrient value of the perennial salt-tolerant plant, however,had not been reported in flowering period at different year. It is necessary to know the ruminal degradability of the plants of each growing year in order to determine the regimen to diet for ruminants. The present experiment,therefore,was undertaken to analyze the digestibility and chemical composition of Ceratoides arborescens as feed for ruminants.

Evaluation of Different Substrates Compositions for Acclimatization of Tissue Culture Taro Plantlets in a Propagator

Taro is cultivated in most Regions of Cameroon and it is affected by taro leaf blight disease since 2010 which has decreased its production. Lack of disease-free planting materials has been a main problem to farmers. This study was carried out at International Institute of Tropical Agriculture (IITA) Yaounde and Institute of Agricultural Research for Development (IRAD) Bambui to assess different substrates for acclimatization of tissue culture taro plantlets in apropagator. No information is available on acclimatization of Cameroonian taro plantlets in different substrates. Taro plantlets from tissue culture were acclimatised in a propagator for six weeks under different substrates, the first substrate consisted of sterile three parts of soil and one part of river sand mixed together (3:1), the second substrate consisted of sterile two parts of soil and two parts of river sand mixed together (2:2), the third substrate consisted of sterile two parts of soil, one part of rice husk and one part of river sand mixed together (2:1:1) and the fourth substrate consisted of sterile one part of soil and three parts of river sand mixed together (1:3). After acclimatisation of the different taroplantlets (Dark green petiole with small leaves (L1), Red petiole with small leaves (L2), Light green petiole with large leaves (L3) and Light green petiole with small leaves (L4) in these four substrates, it was observed that the best growth rate of plant was recorded on substrate sand + soil (1:3). The other substrates showed moderate growth of plants. Substrate sand + soil (1:3) can be recommended for acclimatization of Cameroonian taro plantlets.

橡胶树体胚苗质量调查与分析

天然橡胶是我国重要的战略物资和工业原料,主要来源于橡胶树。橡胶树生长周期长,其苗木质量直接影响天然橡胶产业的发展,橡胶树体胚苗在前期研究中表现一致性好,且具有速生、高产的优势。海南省天然橡胶新型种植材料创新基地是当前规模生产的橡胶树体胚苗的基地,现生产品种有热研73397和热研917。本研究分析比较了热研73397体胚试管苗在2018—2020年间的株高、茎粗、叶片数、主根长等指标的差异性,比较了2020年2个品种各指标的差异性,并对不同年份不同品种进行分级比较,以期阐明橡胶树体胚苗规模生产的情况。结果表明:(1)2018—2020年,热研73397的株高、茎粗、叶片数、主根长度在各区间的比例相当;株高、叶片数、主根长度在3 a间的差异不显著;茎粗在2018和2019年之间差异显著,且3 a均值均在2.00 mm以上,最大值和最小值的差值仅为0.09 mm。(2)2020年,热研73397和热研917体胚苗的株高一致,均值均为8.0 cm,且大部分集中在5.0~10.0 cm,分别占66.13%、66.91%;热研73397和热研917的茎粗范围分别为0.80~4.23 mm、1.13~3.73 mm,均值分别为2.11 mm和2.18 mm,2个品种的茎粗在1.50~3.00 mm之间高度集中,分别占85.94%、83.82%;热研73397和热研917叶片数范围分别为0~6片和1~4片,2个品种叶片数绝大多数为1~3片,分别占88.82%、96.32%,其中热研917叶片数为2片的占比高达52.94%;热研73397的主根长度均值为9.5 cm,而热研917的为9.1 cm,2个品种的主根长度多数集中在8.0~12.0 cm之间,分别占74.12%、79.41%;方差分析结果表明,2020年2个品种的株高、茎粗、叶片数差异不显著,主根长度差异显著(P<0.05)。(3)2018—2020年调查的橡胶树体胚苗中,不同年份不同品种的橡胶树体胚苗,一级苗比例为19%~22%,二级苗比例为56%~62%。据此,规模化生产橡胶树体胚试管苗质量稳定,为橡胶树体胚苗生产工艺的推广应用提供参考。

γ-氨基丁酸对怀玉山三叶青低温胁迫下试管苗生长及相关生理代谢的影响

目的探讨γ-氨基丁酸(GABA)对怀玉山三叶青低温胁迫下试管苗生长及相关生理代谢的影响,为其在怀玉山三叶青仿野生栽培中的防冻抗寒应用提供依据。方法以低温胁迫下GABA处理的怀玉山三叶青试管苗为研究对象,采用植物组织培养法测定其生长指标,植物生理生化法测定其生理指标,实时荧光定量聚合酶链反应(qRT-PCR)法检测其查尔酮合酶和黄酮醇合酶基因的相对表达量。结果与未添加GABA的对照组相比,培养基中添加0.5 g·L^(-1)GABA,怀玉山三叶青2个栽培种“怀玉1号”和“怀玉2号”试管苗的增殖系数、株高、鲜质量、干质量及组织含水量均达到最高值;可以显著提高其可溶性蛋白(SP)、可溶性糖(SS)、脯氨酸(Pro)、还原型谷胱甘肽(GSH)、抗坏血酸(AsA)、吲哚乙酸(IAA)、玉米素核苷(ZR)、赤霉素(GA3)、茉莉酸(JA)的含量,以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)的活性和查尔酮合酶(CHS)基因的相对表达量(RQ值);显著降低其相对电导率、脱落酸(ABA)、过氧化氢(H_(2)O_(2))、丙二醛(MDA)的含量,O_(2)·^(-)产生速率,以及黄酮醇合酶(FLS)基因的相对表达量。低温胁迫下GABA处理的怀玉山三叶青试管苗的生长与IAA、ZR、GA3、JA、SS、AsA、GSH的含量和CHS基因表达呈正相关。结论适当浓度的GABA可以调控内源植物激素和渗透调节物质含量、抗氧化物质含量以及次生代谢物关键基因表达,以促进低温胁迫下怀玉山三叶青试管苗的生长。

碳离子束辐照对马铃薯组培苗生长及生理特性的影响

为研究高能碳离子束对马铃薯组培苗茎切段的影响,以马铃薯品种‘新大坪’的组培苗茎切段为研究材料,设置4个辐照剂量梯度对其进行辐照处理,测定植株致死率、生根率、侧芽形成率、形态变异率以及叶片生理指标,确定‘新大坪’组培苗茎切段的半致死辐照剂量。结果表明:辐照剂量与致死率之间的关系呈正相关性;组培苗茎切段的再生植株表型变化主要为叶片不对称、叶缘不规则、茎变异伸长、叶片丛生和叶片粘连等;随辐照剂量升高,超氧化物歧化酶、过氧化物酶和过氧化氢酶活性呈先升后降的趋势;丙二醛含量则呈先升后降,随后又升高的现象。利用线性回归方程计算‘新大坪’的半致死辐照剂量为20.37 Gy。

珙桐体细胞胚胎发生技术研究

研究探讨基本培养基类型对珙桐愈伤组织诱导的影响、植物生长调节剂对胚性愈伤组织诱导及体胚发育的影响,初步建立以未成熟合子胚为外植体,通过体细胞胚胎发生途径再生珙桐植株的培养方案。结果表明,在含有3%蔗糖、0.3%凝胶、800 mg/L水解酪蛋白、400 mg/L L-谷氨酰胺的MS、1/2MS和WPM基本培养基上均可诱导出愈伤组织,以MS+2.0 mg/L 2,4-D+0.5 mg/L 6-BA诱导率最高,可达94.0%;胚性愈伤组织在MS+0.5 mg/L NAA+1.0 mg/L 6-BA的培养基上诱导效果较好;在MS+0.5 mg/L NAA+1.0 mg/L 6-BA培养基上,体胚诱导率可达22.9%;成熟体胚在1/2MS+0.5 mg/L 6-BA+0.25 mg/L IBA的萌发培养基上能正常萌发,其后在添加1 g/L活性炭的萌发培养基上转化成完整小植株。组织细胞学观察表明,珙桐体胚起源于胚性愈伤组织,经历了球形期、心形期、鱼雷期和子叶期发育阶段,这与自然条件下的合子胚形成过程相似。

云南马铃薯不同品种(系)对马铃薯疮痂病的抗性分析

随着云南省马铃薯种植面积的扩大和种薯调运的频繁,质量监管不足导致马铃薯疮痂病的发生日益严重。本研究旨在评估云南省马铃薯主栽品种对该病害的抗性水平,并筛选出具有潜在抗病性的育种材料。为此,本研究收集了33份不同的马铃薯品种(系)材料,并通过组织培养方法培育组培苗,进而采用盆栽试验进行抗性评估。同时结合对大田主栽品种田间发病情况的调查。结果显示,供试的33份马铃薯品种(系)的组培苗接种疮痂病菌后,所有测试品种均出现了不同程度的病害,发病率58%~96.67%,其中I-1085品种的发病率最低,F37-2品种的发病率最高。病情指数分布在22.58~67.27之间,以Fx3品种的病情指数最低,F37-2的最高。本研究结果为云南省马铃薯抗疮痂病品种选育工作提供了重要的基础性数据和理论支撑。

氮缺乏对84K杨树组培苗光合特性及次生代谢的影响

研究氮缺乏对84K杨树组培苗生长的影响,以期为84K杨的育种与繁殖提供理论基础。以84K杨树组培苗为实验材料,通过氮缺乏处理,测定84K杨树组培苗的生物量、光合参数、叶绿素荧光参数,并进一步分析氮缺乏时全氮、全碳、碳氮比、总酚及抗氧化活性的变化。结果显示:随着培养基中氮含量的减少,84K杨树组培苗的干重、净光合速率(P n)和气孔导度(G s)均受到抑制,同时,氮缺乏导致84K杨树组培苗叶绿素a、叶绿素b、总叶绿素含量及最大光化学效率(Fv/Fm)降低。此外,随着培养基中氮素的减少,84K杨树组培苗中全氮含量显著减少,碳氮比显著升高,总酚含量显著增加。抗氧化分析结果表明,培养基中氮含量越低,组培苗的抗氧化活性越好。相关性分析表明,生物量与光合参数及叶绿素含量之间存在极显著正相关,但与总酚含量之间存在负相关;全氮含量与总酚含量之间存在负相关,与全碳及碳氮比之间存在正相关;同时84K杨树组培苗总酚含量及抗氧化活性之间具有明显的相关性。研究结果表明:氮缺乏可对84K杨树组培苗的光合生理及次生代谢产物产生影响,不利于84K杨树组培苗的生长和光合作用,但促进了多酚等抗氧化物质的产生。本研究可为84K杨树的栽培管理提供理论依据和基础数据。

金钗石斛组培苗壮苗培养研究

为研究金钗石斛组培苗快速生长的影响因素,以生长素NAA、水解乳蛋白、MS培养基有机成分、活性炭四因素三水平设置正交试验,观察金钗石斛组培苗壮苗培养的生长表现,从而确定最佳培养基组合。试验结果表明:0.10 g/L活性炭+0.50 mg/L NAA+0.05 g/L水解乳蛋白+1倍有机成分组合对组培苗各生长效果最好;加入NAA可以明显增加组培苗生长的高度和茎粗。本研究可为金钗石斛组培快繁研究奠定基础。

In vitro callus induction and plantlet regeneration of Achyranthes aspera L.,a high value medicinal plant

Objective:To study callus induction from different explants(internode,leaf,root)and in vitro plantlets propagation from medicinally important plant Achyranthes aspera L.Methods:Sterilized explants were prepared by uning 0.1%HgCl_2 and 0.5%Bavistin and callus was obtained when cultured onto Murashige Skoog's(MS)medium by using different concentrations and combination of 2,4-D.NAA.BAP,IAA,IBA with 3%sucrose and 0.8%agar.Induced callus was immediately transferred to MS medium containing at different concentrations of phytohormones for shootlets and rootlets induction respectively.Results:Sterilization treatment of 0.1%HgCl_2.for 2-3 min and Bavistin 0.5%for 10-12 min showed the highest percentage of asepsis and survival rate.Maximum induction of callus was obtained from a combination of 2.0 mg/L 2,4-D and 0.5 mg/L NAA from leaf.Highest shootlets number(4.83±0.l7)and length(3.8±0.16)cm were observed on full strength MS medium when fortified with BAP 4.0 mg/L and KIN 0.5 mg/L.Concerted efforts of BAP 10 mg/L and NAA 0.5 mg/L on full strength MS medium showed highest leaf number(6.77±0.94).In vitro raised shoots were allowed to root on different strengths of MS medium fortified with IAA and IBA at different concentrations.Experimentally,3.0 mg/L IBA was enabled to induce maximum rootlets number(10.0±9.82)on full strength MS medium.Afterwards,regenerated shoots with well developed roots were successfully subjected to hardening process and were acclimatized.The survived plantlets showed 66.67%survival frequency without any morphological abnormality.Conclusions:The results demonstrated that different explants were good source of callus induction,morphology analysis as well as indirect plantlets regeneration.

Effects of Lanthanum and Europium on Rooting of Plantlet Eriobotrya Japonica Lindl. in vitro

The effect of La 3+ and Eu 3+ on the rooting of Eriobotrya japonica Lindl. plantlet in vitro was studied with adding La 3+ and Eu 3+ to the rooted medium. The rooting rate, the number of root and the length of root were studied after transplanting 20 d. The activity of peroxidase, nitrate reductase and fresh weight of roots were determined after transplanting 44 d. The results show that the optimum concentration range of La 3+ (1.0～3.0 μmol·L -1), Eu 3+ (2.0～3.0 μmol·L -1) in the rooted medium can increase the rooting rate and the fresh weight of roots, and promote the length of root and raise the activities of peroxidase and nitrate reductase significantly. La 3+ has more effect in improving the rooting rate, root length and the activities of peroxidase and less effect in promoting root fresh weight and the activities of nitrate reductase than Eu 3+.

Effects of different LEDs light spectrum on the growth,leaf anatomy,and chloroplast ultrastructure of potato plantlets in vitro and minituber production after transplanting in the greenhouse

Light spectrum plays an important role in regulating the growth and development of in vitro cultured potato(Solanum tuberosum L.) plantlets. The status of potato plantlets at the end of in vitro stage influences the minituber production after transplanting. With 100 μmol m^-2s^-1 total photosynthetic photon flux density(PPFD), a light spectrum study of 100% red light emitting diodes(LEDs) light spectrum(RR), 100% blue LEDs light spectrum(BB), 65% red+35% blue LEDs light spectrum(RB), and 45% red+35% blue+20% green LEDs light spectrum(RBG) providing illumination at the in vitro cultured stage of potato plantlets for 4 weeks using fluorescent lamp as control(CK) was performed to investigate the effects of LEDs light spectrum on the growth, leaf anatomy, and chloroplast ultrastructure of potato plantlets in vitro as well as the minituber yield after 2 months transplanting in the greenhouse. Compared to CK, RB and RBG promoted the growth of potato plantlets in vitro with increased stem diameter, plantlet fresh weight, plantlet dry weight, and health index. Furthermore, BB induced the greatest stem diameter as well as the highest health index in potato plantlets in vitro. Root activity, soluble protein, and free amino acid were also significantly enhanced by BB, whereas carbohydrates were improved by RR. In addition, thickness of leaf, palisade parenchyma and spongy parenchyma was significantly increased by BB and RBG. Chloroplasts under BB and RBG showed well-developed grana thylakoid and stroma thylakoid. Unexpectedly, distinct upper epidermis with greatest thickness was induced and palisade parenchyma and spongy parenchyma were arranged neatly in RR. After transplanting in the greenhouse for 2 months, potato plantlets in vitro from BB, RB, and RBG produced high percentage of large size tuber. BB improved fresh and dry weights of the biggest tuber but decreased tuber number per plantlet. In addition, RBG increased tuber number as well as tuber fresh and dry weight slightly. Our results suggested monochromatic blue LEDs as well as combined red, blue or/and green LEDs light spectrum were superior to fluorescent lamp spectrum in micro-propagation of potato plantlets. Therefore, the application of RBG was suitable;BB and RB could be used as alternatives.

Putrescine Plays a Positive Role in Salt-Tolerance Mechanisms by Reducing Oxidative Damage in Roots of Vegetable Soybean

Polyamines play important roles in plant tolerance to environmental stress. With the aim of investigating the possible involvement of putrescine （Put） in salt-tolerance mechanisms in vegetable soybean roots, exogenous Put （10 mmol L＂） and its biosynthetic inhibitor D-arginine （D-Arg） （0.5 mmol L-1） were added to nutrient solution when vegetable soybean （Glycine max L. cv. Huning 95-1） seedlings were exposed to 100 mmol L^-11 sodium chloride （NaCl）. The results showed that Put ameliorated but D-Arg aggravated the detrimental effects of NaCl on plant growth and biomass production. Under NaCl stress, levels of free, soluble conjugated and insoluble bound types of Put in roots of vegetable soybean were reduced, whereas those of free, soluble conjugated, and insoluble bound types of spermidine （Spd） and spermine （Spm） were increased. Exogenous Put eliminated the decrease in Put but promoted the increase of Spd and Spm. However, these changes could be reversed by D-Arg. Under NaCl stress, activities of arginine decarboxylase （ADC）, S-adenosylmethionine decarboxylase （SAMDC）, diamine oxidase （DAO）, and polyamine oxidase （PAO） were induced, with exogenous Put promoting and D-Arg reversing these changes. Furthermore, NaCl stress decreased activities of antioxidant enzymes. Exogenous Put alleviated but D-Arg exaggerated these effects of NaCl stress, resulting in the same changes in membrane damage and reactive oxygen species （ROS） production. These results indicated that Put plays a positive role in vegetable soybean roots by activating antioxidant enzymes and thereby attenuating oxidative damage.

Effect of mini-cutting size on adventitious rooting and morphophysiological quality of Ilex paraguariensis plantlets

As the energizing and therapeutic effects of infusions of mate(Ilex paraguariensis A.St.-Hil)leaves are increasingly recognized,rising global consumption is also increasing the demand for plantlets with high genetic and morphological qualities.Mini-cuttings are an alternative for clonal plantlets;however,more details are needed on factors that affect the success of this technique.Here,toward maximizing production,we evaluated adventitious rooting competence of mini-cuttings of different sizes and the morphophysiological quality of the resultant plantlets.Small(one bud;length up to 2.5 cm),medium(multiple buds;length 2.6–5.0 cm),and large(multiple buds;length 5.1–10.0 cm)mini-cuttings were planted in a mixture of commercial substrate,vermiculite,and coarse sand(1:1:1 v:v:v),grown in a humidity chamber,then evaluated after 45,60,75,and 90 days for survival,percentage of callus and shoot formation,number and length of shoots,percentage of rooted cuttings,and number and length of roots.Any rooted mini-cuttings were then cultivated in commercial substrate and subsurface soil(2:1 v:v)and evaluated after 30,60,90 and 120 days of cultivation for morphophysiology of the plantlets,percentage of survival,number of leaves,shoot height,stem diameter,and ratio of shoot height to stem diameter.After 120 days,the plantlets were evaluated for the ratio of shoot and root dry mass,total length,surface area,total volume,and mean diameter of roots and Dickson quality index.Adventitious rooting of the mini-cuttings and the morphophysiological quality of the plantlets were not influenced by the size of the vegetative propagule.Therefore,single-bud mini-cuttings have similar adventitious rooting competence,and result in plantlets with adequate morphophysiological quality,based upon leaf development,shoot height,stem diameter and length,and surface area,volume and diameter of roots.Single-bud mini-cuttings up to 2.5 cm long can thus be used to maximize production of mate plantlets by mini-cuttings.