接种乳酸菌对发酵萝卜品质及亚硝酸盐含量的影响

单一或混合接种植物乳杆菌SD-7(Lactobacillus plantarum SD-7)、植物乳杆菌9sh(Lactobacillus plantarum9sh)和干酪乳杆菌L3(Lactobacillus casei L3)来发酵萝卜,对发酵过程中萝卜泡菜的硬度、感官品质、亚硝酸盐含量及p H值进行了分析。结果表明:接种乳酸菌发酵萝卜能明显降低萝卜中亚硝酸盐的含量,缩短发酵周期,其中混合接种SD-7+L3(1∶1)发酵萝卜所得泡菜的亚硝酸盐含量最低,感官品质最佳,硬度较好。     

Molecular Characterization and Expression Profiles of Myrosinase Gene（RsMyr2） in Radish（Raphanus sativus L.）

Myrosinase is a defense-related enzyme and is capable of hydrolyzing glucosinolates into a variety of compounds, some of which are toxic to pathogens and herbivores. Many studies revealed that a number of important vegetables or oil crops contain the myrosinase-glucosinolate system. However, the related promoter and genomic DNA sequences as well as expression profiles of myrosinase gene remain largely unexplored in radish（Raphanus sativus）. In this study, the 2 798 bp genomic DNA sequence, designated as RsMyr2, was isolated and analyzed in radish. The RsMyr2 consisting of 12 exons and 11 introns reflected the common gene structure of myrosinases. Using the genomic DNA walking approach, the 5′-flanking region upstream of RsMyr2 with length of 1 711 bp was successfully isolated. PLACE and PlantCARE analyses revealed that this upstream region could be the promoter of RsMyr2, which contained several basic cis-regulatory elements including TATA-box, CAAT-box and regulatory motifs responsive to defense and stresses. Furthermore, recombinant pET-RsMyr2 protein separated by SDS-PAGE was identified as myrosinase with mass spectrometry. Real-time PCR analysis showed differential expression profiles of RsMyr2 in leaf, stem and root at different developmental stages（e.g., higher expression in leaf at cotyledon stage and lower in flesh root at mature stage）. Additionally, the RsMyr2 gene exhibited up-regulated expression when treated with abscisic acid（ABA）, methyl jasmonate（MeJA） and hydrogen peroxide（H2O2）, whereas it was down-regulated by wounding（WO） treatment. The findings indicated that the expression of RsMyr2 gene was differentially regulated by these stress treatments. These results could provide new insight into elucidating the molecular characterization and biological function of myrosinase in radish.     

不同播期对萝卜杂交种种子质量和产量的影响

为了在云南开发萝卜杂交种子生产基地,以雄不育系和自交不亲和系为萝卜亲本的试材,进行不同播期的生产试验,研究萝卜各处理间的生长期、种子产量和质量等方面的差异。结果表明：播期与生长量呈正比,不同播期对开花期没有明显的影响,但对萝卜种子的产量和质量有显著影响,10月15日播种生产出的萝卜种子的产量和质量最好。     

共消化污泥施用对贫瘠土壤性质和蔬菜品质的影响

将市政污泥、餐厨垃圾和果蔬垃圾的共消化污泥进行农业利用,通过分析土壤和蔬菜中营养元素和重金属含量,研究共消化污泥对土壤营养元素变化、蔬菜养分吸收、土壤重金属累积、蔬菜重金属积累的影响。结果表明,共消化污泥施用显著提高了土壤有机质、总氮、总磷含量,且提高幅度与共消化污泥的施用量呈线性关系,同时促进了蔬菜对氮、磷的吸收和利用,但土壤总钾含量和蔬菜对钾的吸收受共消化污泥施用影响较小。共消化污泥施用后,土壤中Zn、Cu和Cd含量增加,尤其是Cd含量增加较明显,并且在蔬菜中累积,但土壤重金属含量均低于土壤环境质量标准二级标准规定的限值,蔬菜可食部分中Cu、Zn、Cr和Cd含量均低于食品中污染物限量规定的限值。因此,在共消化污泥农业利用过程中,仍需重点关注重金属含量的变化和累积。     

Are road verges corridors for weed invasion? Insights from the fine‐scale spatial genetic structure of Raphanus raphanistrum

Raphanus raphanistrum (Brassicaceae) is considered amongst the world's worst agricultural weeds. We address critical issues in its management by studying the pathway of colonisation at local scales. For this, we assessed the small‐scale spatial genetic structure of 231 samples collected from three different sites across the Cape Floristic Region, South Africa, using 11 nuclear microsatellite markers. Although natural pollen and seed dispersal were expected to be restricted, we found no significant relationship between genetic and geographical distance within sites. Instead, our results suggest that R. raphanistrum had colonised new habitats via jump dispersal, rather than through natural diffusive dispersal at local scales. We did not find evidence for road verges as dispersal corridors, as evidenced by a lack of isolation‐by‐distance at local scales. Instead, the absence of spatial genetic structure suggests that R. raphanistrum had rapidly spread throughout its current range, possibly facilitated by human‐mediated actions. Management plans addressing containment or suppression of the weedy species R. raphanistrum (and possibly other weedy species) should take the high degree of connectivity between distant geographical localities into account.     

The present status of biological control of Xanthium (Compositae)

Abstract

The economic threshold level of the mustard aphid, Lipaphis erysimi (Kaltenbach) was determined on the radish seed crop, var Punjab Sufed. Spraying oxydemeton methyl at 300 g a.i./ ha, was monitored at arbitrary set aphid levels from 25 to 150 aphids/plant. The maximum cost benefit ratio (1: 13.1) was achieved at an aphid level of 50 per plant, requiring three sprays. Spraying in the middle of February was the most crucial, as delay of 7 days from this stage resulted in significant decreases in yield in the fixed spray schedule and at the 75‐aphid level.     

同工酶酶谱鉴定萝卜品种的初步研究

采用聚丙烯酰胺凝胶电泳对４个萝卜品种的酯酶（ＥＳＴ）、酸性磷酸酯酶（ＡＣＰ）同工酶进行了初步研究。结果表明：ＥＳＴ谱带只能区分开所的３个品种,ＡＣＰ谱带能将所研究的４个品种区分开。     

从萝卜下胚轴再生完整植株

以萝卜无菌幼苗下胚轴为外植体,研究了不同基因型萝卜品种,不同浓度的NAA、BA、蔗糖、AgNO3对植株再生的影响。基本培养基(BM)为MS无机盐 Gly2mgL 肌醇2mgL 烟酸05mgL VB101mgL 琼脂68gL。试验证明萝卜离体再生主要受基因型和BA、NAA浓度影响。从自交系小红头下胚轴愈伤组织产生的绿色子叶状团块在提高BA、NAA浓度的培养基中大量增殖;降低激素浓度,尤其是BA浓度后,这些子叶状簇生团块发育成大量无根苗,叶片正常。无根苗在添加不同种类的生长素的培养基中生根,并成功地移植入田间。本实验也对AgNO3的作用进行了研究和讨论。     

萝卜收获机振动松土铲参数的优化

为了确定萝卜收获机振动松土铲的关键参数,利用偏心连杆式振动装置进行松土试验,以机器行走速度、松土铲激振频率和振幅、铲入土角、铲刃倾角作为试验影响因素,土壤孔隙度为响应指标,并采用二次正交旋转回归试验设计,建立了响应指标与各影响因素之间回归数学模型。通过Design-Expert 6.0软件对试验参数进行优化,确定机器行走速度0.64?m/s、激振器频率2?Hz、振幅14.38?mm、铲入土角25.72°、铲刃倾角39.68°为最优参数组合,此时土壤孔隙度为50%～60%,该研究为研究和设计萝卜收获机提供依据。     

红光处理对萝卜芽菜采后贮藏过程中芥子油苷和抗氧化能力的影响

为探究红光处理对萝卜芽菜采后营养品质的影响,本试验对采收后的萝卜芽菜进行8 h红光处理,之后置于4℃条件下贮藏,于贮藏0、1、2和3 d对其芥子油苷,叶绿素、花青素等抗氧化物质含量,以及总抗氧化能力进行分析。结果表明,与对照相比,红光处理使萝卜芽菜中的脂肪类芥子油苷(4-甲硫基-3-丁烯基芥子油苷等)和吲哚类芥子油苷(4-甲氧基-吲哚-3-甲基芥子油苷等)含量分别提高9.5%和20.6%,并且延缓了贮藏过程中具有抗癌活性的4-甲硫基-3-丁烯基芥子油苷含量的下降。此外,红光处理提高了萝卜芽菜中叶绿素和花青素的含量,以及贮藏早期的抗氧化能力。本研究结果为通过光照处理维持萝卜芽菜采后品质提供了理论依据,具有潜在的应用价值。