陕西省双低油菜硫苷含量的稳定性分析

采用HPLC法对陕西省冬油菜区5个试区种植的双低油菜籽粒中硫苷总量和组分含量进行了分析,结果表明: 1 陕西省不同地区的生态条件对双低油菜总硫苷含量有显著的影响,相差达13.14μmol/g,CV为13.30%,5个试区硫苷含量的排序为宝鸡>安康>咸阳>大荔>汉中,地区间达显著或极显著差异;品种间硫苷含量的稳定性有明显的差异,以P01-10品种稳定性最好; 2 在测定的8个硫苷组分中,变幅最大的5个组分依次为2-羟基-3-丁烯基硫苷、4-羟基-3吲哚甲基硫苷、4-戊烯基硫苷、3-丁烯基硫苷和2羟基-4-戊烯基硫苷,极差分别为:5.70、2.69、1.70、1.31和1.03μmol/g,变异系数分别为:17.59%、16.41%、58.84%、10.21%和50.32%,其中以3-丁烯基硫苷稳定性最好,4-戊烯基硫苷稳定性最差; 3 籽粒中硫苷与含油量、千粒重及容重均有显著的相关性,相关系数分别为-0.783、-0.948和0.656,通径和偏相关分析表明,仅硫苷与千粒重偏相关显著为-0.859,含油量和容重是通过千粒重来影响硫苷的.     

四个芸薹属物种硫苷含量与种类分析及特殊硫苷成分的种间导入

硫代葡萄糖苷(简称硫苷)是在十字花科植物中广泛存在的一类次级代谢物,在植物防御体系中发挥着重要的作用。本研究通过高效液相色谱(HPLC)技术,检测分析了十字花科芸薹属4个油用物种(甘蓝型油菜、埃塞俄比亚芥、芥菜型油菜、白菜型油菜)67个代表性品种3个器官(根、叶、种子)3个环境(2014年湖北武汉、2016年湖北武汉、2016年湖北襄阳)下的硫苷种类及含量。共检测到11种主要的硫苷,显著性检验结果显示:不同年份间硫苷含量分布差异极显著,但在同一年武汉与襄阳两个地点间差异不显著;不同物种间硫苷的类型差异明显;甘蓝型油菜、埃塞俄比亚芥不同品种间硫苷含量分布差异极显著,但受测的芥菜型油菜、白菜型油菜不同品种间硫苷含量分布差异不显著;同一个品种不同器官间的硫苷总量差异极显著;同一器官不同硫苷的含量差异也极为显著。这些结果表明硫苷在不同物种、不同器官、不同品种间都展现了丰富的变异,同时硫苷也受到了极显著的环境影响。每个物种或物种的不同器官内都有其代表性的特殊硫苷成分,如甘蓝型油菜中的2-羟基-3-丁烯基硫苷,埃塞比亚芥以及芥菜型油菜中的2-丙烯基硫苷,白菜型油菜中的3-丁烯基硫苷。其中一些特殊硫苷成分具有有益的生物学功能,它们的存在为通过种间杂交的方式将其向甘蓝型油菜中聚集提供了可能性。我们以在埃塞俄比亚芥与芥菜型油菜中所检测到的具有抗病功能的2-丙烯基硫苷为例进行展示,这种硫苷成分在高、中、低硫苷的甘蓝型油菜品种中含量都几乎为0,而在含有埃塞俄比亚芥与白菜型油菜亚基因组导入片段包含3个世代183个株系的再合成甘蓝型油菜(新型甘蓝型油菜)中,有170个株系检测到了显著高于品种材料的2-丙烯基硫苷成分,这说明了通过种间交流的方式向目标物种中导入特殊硫苷成分的可行性。以上这些结果将为分析利用芸薹属不同油用作物中的硫苷,并创建具有特殊硫苷成分的芸薹属作物提供信息和新的视角。     

外源喷施萘乙酸对小白菜硫代葡萄糖苷的影响

本试验研究了不同浓度的萘乙（NAA）并结合单次喷施（NAA-1）和两次喷施（NAA．2）,对小白菜生长和硫代葡萄糖苷（简称硫苷）含量的影响。结果表明,与对照相比,不同的NAA处理浓度均显著增加了小白菜的鲜重。同时,NAA处理对总硫苷和单个硫苷含量产生了显著的影响。NAA-1处理时,总脂肪族硫苷、2．苯乙基硫苷和总硫苷在20mg·L-1时到达最大值;而总吲哚族硫苷在50mg·L-1时含量到达最高。NAA．2处理时,大部分单个硫苷和总硫苷在10mg·L-1处理即达到最大值。可见,在较低浓度两次喷施NAA试验中对大部分硫苷的诱导效果高于单次喷施NAA;但随着NAA处理浓度的提高,单次喷施NAA对硫苷的诱导效果较好。其中,吲哚-3-甲基硫苷含量在NAA-1处理,喷施50mg·L-1时显著高于其他处理：而2-苯乙基硫苷在单次和两次喷施NAA时,分别在20mg·L-1和10mg·L-达到了最大值。     

蝇蛆几丁低聚糖对草莓保鲜作用研究

两种蝇蛆几丁低聚糖对7种草莓病原菌的抑制作用,试验结果表明酶解几丁低聚糖的抑菌活性显著高于H2O2水解几丁低聚糖,质量浓度10g/ml时,它对草莓灰霉菌等6种病原菌有强烈的抑制作用,抑菌效果在80%以上,但对草莓白粉菌的抑制作用一般;H2O2水解几丁低聚糖对草莓灰霉菌等4种病原菌也有很好的抑制效果,对草莓黑霉病菌等3种病原菌的抑制作用较差.盆栽试验结果表明蝇蛆几丁低聚糖喷雾处理可以减少生长期草莓果实的发病率,处理后第3天即表现出一定的防病效果,处理后第6天防病效果最佳,处理后第9天,防病效果开始有所下降.涂膜处理试验结果表明,在常温下,10～20mg/ml几丁低聚糖溶液处理,可使草莓的保存期延长2～3天.     

锡尾矿链霉菌AE21985代谢产物的分离与鉴定

采用硅胶柱、凝胶柱层析、高效液相制备等方法从分离自云南锡尾矿土壤的链霉菌AE21985发酵液中分离到19个化合物,通过波谱学方法鉴定为11个环二肽类化合物:3-(4-羟基苄基)-6-(1H-吲哚-3-基甲基)哌嗪-2,5-二酮(1)、(3S,6S)-3-((R)-仲-丁基)-6-甲基哌嗪-2,5-二酮(2)、(3S)-3-苄基哌嗪-2,5-二酮(3)、(3S,6S)-3-(2-甲基丙基)-6-(丙-2-基)哌嗪-2,5-二酮(4)、3-异丁基六吡咯并[1,2-α]吡嗪-1,4-二酮(5)、(3S,6S)-3-((R)-仲-丁基)-6-甲基哌嗪-2,5-二酮(6)、(3S,6S)-3-异丙基-6-甲基哌嗪-2,5-二酮(7)、(3S,7R,9S)-7-羟基-3-异丁基六吡咯并[1,2-α]吡嗪-1,4-二酮(8)、3-(1H-吲哚-3-基甲基)-6-(丙-2-基)哌嗪-2,5-二酮(9)、(3S,8a S)-3-(丙-2-基)六氢吡咯并[1,2-α]吡嗪-1,4-二酮(10)及(3S,6S)-3-苄基-6-甲基哌嗪-2,5-二酮(11);5个酰胺类化合物:(2E)-3-苯基丙-2-烯酰胺(12)、3-苯基丙酰胺(13)、2-苯基乙酰胺(14)、苯甲酰胺(15)及3-(1H-吲哚-3-基)丙酰胺(16);1个生物碱类物质:1H-吲哚-5-甲醛(17);2个核苷类物质:尿苷(18)及胸腺嘧啶(19)。这些化合物均为首次从该菌株中发现。     

萝卜和白菜属间杂种硫甙基因表达与组分特征分析

硫甙是十字花科蔬菜中重要的次生代谢物质。在不同的十字花科作物中,硫甙的种类及其降解产物不同,从而产生了各自的特殊风味与生物功能。萝卜的主要硫甙4-甲基亚磺酰基-3-丁烯基硫甙(RAE)及其降解产物具有强力的抗癌活性;而白菜的主要硫甙2-羟基-3-丁烯基硫甙(PRO)的降解产物噁唑烷硫酮,被认为有致甲状腺肿大的副作用。本研究采用高效液相色谱分析法,分析了萝卜(‘36-2’)、白菜(‘Chiifu’)以及属间杂种(DH)中硫甙组分及其含量,共鉴定出13种硫甙。萝卜中的主要硫甙是4-甲硫基-3-丁烯基硫甙(RSA)和RAE;白菜中的主要硫甙为PRO、3-丁烯基硫甙(NAP)和吲哚-3-甲基硫甙(GBC);远缘杂交种的主要硫甙则有RAE、4-戊烯基硫甙(GBN)、NAP和PRO。通过与‘36-2’的比较转录组分析,发现DH中硫甙通路基因有14个下调表达和23个上调表达,其中萝卜特有基因RsIQD1.1和RsMYB34.2下调表达,而RsMYB34.1上调表达。值得注意的是萝卜中的RsFMOGS-OX2.1在DH中显著上调表达。通过与‘Chiifu’的比较分析,发现DH中硫甙通路基因有24个下调表达和15个上调表达,其中白菜特有基因BrIPMI-SSU3.1、BrIPMDH3.1和BrMAM3.1显著上调表达。这些基因在不同物种中的表达特点与其硫甙组分的变化有关。这在一定程度上证实远缘杂交可能通过改变后代的遗传组成和基因表达而改变其硫甙组成及含量,为以属间杂种作为桥梁种质实现物种间基因交流,创制高品质十字花科新种质奠定了理论基础和技术支撑。     

蒸腾作用及根系特征对不同品种油菜吸收镉的影响

采用营养液培养试验研究了12个油菜品种地上部的镉含量、蒸腾速率和根系形态特征(根长、根表面积、根体积),并对不同品种油菜地上部镉含量与蒸腾速率和根系形态特征进行了相关分析。结果表明:不同品种油菜对镉的吸收累积有显著差异,油菜地上部镉含量以鲜质量计为1.8～4.4mg·kg-1,相差1.5倍,同时不同品种油菜的蒸腾速率与根系形态均存在显著性差异;蒸腾速率和根表面积、根体积均与不同油菜品种地上部镉浓度、吸镉总量呈显著正相关(P0.01),根长只与油菜吸镉总量呈显著正相关,表明高的蒸腾强度和发达的根系均能促进油菜地上部镉的累积量。     

靛红衍生物的合成及其对稻瘟菌的生物活性

以靛红为原料合成了系列3-亚胺基/亚甲基-吲哚-2-酮化合物及其Mannich碱衍生物,研究了它们在抗稻瘟菌方面的活性,发现了这两种类型的若干化合物有较好的抑制稻瘟菌孢子萌发的活性,初步讨论了构效关系。认为1位的羟甲基和胺甲基、3位的亚甲基是药效团,芳基亚甲基苯环上对位取代基、羟基取代基和吸电子取代基不利于活性的提高,邻位的供电子取代基有利于活性的提高。     

灰毛豆内生真菌淡紫拟青霉菌(TPL04)代谢产物的研究

从灰毛豆叶片中分离出内生真菌-淡紫拟青霉菌Purureocillium lilacinum(TPL04),对其发酵产物采用硅胶柱色谱、Sephadex LH-20凝胶色谱、制备薄层色谱、中压柱色谱及制备液相色谱等方法进行分离纯化,共获得8个单体化合物。通过波谱学方法并结合相关文献数据比对,化合物结构鉴定为5-羟基己酸-4-内酯(1)、(R)-4-苄基-2-噁唑烷酮(2)、2′-脱氧胸苷(3)、对羟基苯甲酸甲酯(4)、光色素(5)、β-胡萝卜苷(6)、尿嘧啶核苷(7)、己六醇(8)。其中化合物1、2、4是首次从淡紫拟青霉菌中分离得到,抑菌实验表明化合物4对水稻纹枯菌(Pellicularia sasakii)、辣椒疫霉菌(Phytophthora capsici)、草莓灰霉菌(Botrytis cinerea)、油菜菌核菌(Sclerotinia sclerotiorum)四种植物病原菌生长有抑制作用。     

烤烟根系分泌物中单糖的组分含量及其相关分析

以4个不同烤烟品种为研究材料,采用盆栽试验,运用高效毛细管区带电泳法测定各品种根际土、非根际土、根系及叶片中的单糖组分及含量,并分析其相关关系,探究根系分泌物中糖类的分泌特性。结果表明：在各样品中,共检出木糖、葡萄糖、半乳糖、核糖、阿拉伯糖和鼠李糖6种糖;不同品种根际土、非根际土、根系及叶片中检出的糖组分及含量均存在差异;同一品种中,叶片最高,根系次之,根际土和非根际土最低;相关性分析表明,木糖、阿拉伯糖、葡萄糖、鼠李糖和半乳糖总量在根际土、非根际土、叶片和根系间呈正相关关系,各单糖组分间均呈正相关关系,部分组分呈显著或极显著相关关系。研究表明,不同烤烟品种根系分泌这些单糖存在品种差异,且根系分泌单糖可能是一个沿浓度梯度的扩散过程。     

Phytochemical fingerprinting of vegetable Brassica oleracea and Brassica napus by simultaneous identification of glucosinolates and phenolics

Introduction – Brassica vegetables have been related to the prevention of cancer and degenerative diseases, owing to their glucosinolate and phenolic content. Objective – Identification of glucosinolates, flavonoids and hydroxycinnamic acids in representative varieties of kale, cabbage and leaf rape. Methodology – One local variety of each crop was evaluated in this study using a multi‐purpose chromatographic method that simultaneously separates glucosinolates and phenolics. Chromatograms were recorded at 330 nm for flavonoid glycosides and acylated derivatives and 227 nm for glucosinolates. Results – Eight glucosinolates were identified in kale and cabbage, which exhibited the same glucosinolate profile, and 11 glucosinolates were identified in leaf rape. Furthermore, 20 flavonoids and 10 hydroxycinnamic acids were detected in kale and cabbage, while 17 flavonoids and eight hydroxycinnamic acids were found in leaf rape. Conclusions – This study has provided a deeper and comprehensive identification of health‐promoting compounds in kale, cabbage and leaf rape, thus showing that they are a good source of glucosinolates and phenolic antioxidants. Copyright © 2011 John Wiley & Sons, Ltd.     

Glucosinolates in oilseed rape (Brassica napus) and the incidence of pollen beetles (Meligethes aeneus)

During an early stage of migration into a field of oilseed rape in the spring of 1988, more pollen beetles were observed on the double-low variety, Ariana, than on the adjacent single-low varieties, Bienvenu and Mikado. More beetles were found on open flowers on terminal racemes than on yellow and green flower buds on lateral racemes. Five alkenyl, three indolyl and two aromatic glucosinolates were identified in the floral tissues of oilseed rape. The major compounds were progoitrin (2-OH, 3-butenyl) and glucobrassicanapin (4-pentenyl). There were no differences in the types and concentrations of glucosinolates present in the terminal and lateral racemes of any variety, and only small differences between single- and double-low varieties. Concentrations of glucosinolates in floral tissues of crops grown with a little nitrogen were twice those of well-fertilised crops. There was no association between the number and distribution of pollen beetles on plants and the amounts or types of glucosinolates present in floral tissues.     

不同品种(系)小豆根系活力与叶片衰老的关联研究

以高产小豆品种(系)‘2000-75’、‘冀红9218’和低产品种(系)‘红宝1号’、‘湾选1号’为材料,测定小豆开花至成熟期,根系与始花节位叶片生长指标、保护酶活性、可溶性蛋白含量等变化,分析其根系与始花叶协同衰老的相关性,以揭示小豆根系活力与地上部叶片衰老之间的关系。结果表明:(1)各品种(系)开花后,植株根系伤流强度随着花后生育进程的推进呈单峰增长趋势,但根系活力的衰老起始期晚于叶片功能的衰退开始期。(2)从开花至成熟期,小豆根系活力与叶片中超氧化物歧化酶、过氧化氢酶、叶绿素含量、可溶性蛋白、叶片净光合速率都存在正相关关系,与丙二醛含量呈负相关关系。(3)与低产品种相比,高产小豆品种(系)‘2000-75’和‘冀红9218’的根系活力强,叶片功能期持续时间长,叶绿素含量下降速度慢,保护性酶含量高,使花后小豆的功能叶捕获光能的能力增强,从而形成较高光合能力的小豆群体,最终获得高产。     

源自不同寄主的灰葡萄孢生物学特性的比较研究

本研究以分离自番茄、辣椒、草莓、葡萄的灰葡萄孢Botrytis cinerea为供试菌株,从生长温度、pH适应性、碳源、氮源营养利用等方面对不同寄主来源的灰葡萄孢菌株的生物学性状进行了比较研究。结果表明,5个不同寄主来源的灰葡萄孢菌株的菌丝生长温度范围相同,均为0-35℃;但它们的最适生长温度和分生孢子致死温度存在差异,来自和县番茄菌株HX12最适生长温度为20℃,分生孢子致死温度为47℃ 10min,其余最适生长温度均为25℃,分生孢子致死温度均为48℃ 10min;不同菌株在相同温度下的生长速率有显著差异。pH对不同寄主来源灰葡萄孢菌株菌丝生长的影响存在差异,来自长丰辣椒的菌株LJ菌丝在pH2-9的范围内均能生长,以在pH3-6.5时生长较快,pH6时最快;其余4个菌株在pH2-12的范围内均能生长,以在pH3-9时生长较快,pH6左右最快。不同碳源、氮源营养对灰葡萄孢菌株菌丝生长和分生孢子产生均有显著影响,不同寄主来源的菌株间在碳源、氮源营养利用差异均极显著。在相同碳源、氮源营养条件下,不同寄主来源的菌株的线性生长、菌丝干重和分生孢子产量均有显著差异。     

Co-ordinated growth between aerial and root systems in young apple plants issued from in vitro culture

BACKGROUND AND AIMS: In several species exhibiting a rhythmic aerial growth, the existence of an alternation between root and shoot growth has been demonstrated. The present study aims to investigate the respective involvement of the emergence of new organs and their elongation in relation to this phenomenon and its possible genotypic variation in young apple plants. METHODS: Two apple varieties, X6407 (recently named 'Ariane') and X3305 ('Chantecler' x 'Baujade'), were compared. Five plants per variety, issued from in vitro culture, were observed in minirhizotrons over 4 months. For each plant, root emergence and growth were observed twice per week. Growth rates were calculated for all roots with more than two segments and the branching density was calculated on primary roots. On the aerial part, the number of leaves, leaf area and total shoot length were observed weekly. KEY RESULTS: No significant difference was observed between varieties in any of the final characteristics of aerial growth. Increase in leaf area and shoot length exhibited a 3-week rhythm in X3305 while a weaker signal was observed in Ariane. The primary root growth rate was homogeneous between the plants and likewise between the varieties, while their branching density differed significantly. Secondary roots emerged rhythmically, with a 3-week and a 2-week rhythm, respectively, in X3305 and 'Ariane'. Despite a high intra-variety variability, significant differences were observed between varieties in the secondary root life span and mean length. A synchronism between leaf emergence and primary root growth was highlighted in both varieties, while an opposition phase was observed between leaf area increments and secondary root emergence in X3305 only. CONCLUSION: A biological model of dynamics that summarizes the interactions between processes and includes the assumption of a feedback effect of lateral root emergence on leaf emergence is proposed.     

Effects of glucosinolates and flavonoids on colonization of the roots of Brassica napus by Azorhizobium caulinodans ORS571

Plants of Brassica napus were assessed quantitatively for their susceptibility to lateral root crack colonization by Azorhizobium caulinodans ORS571(pXLGD4) (a rhizobial strain carrying the lacZ reporter gene) and for the concentration of glucosinolates in their roots by high-pressure liquid chromatography (HPLC). High- and low-glucosinolate-seed (HGS and LGS) varieties exhibited a relatively low and high percentage of colonized lateral roots, respectively. HPLC showed that roots of HGS plants contained a higher concentration of glucosinolates than roots of LGS plants. One LGS variety showing fewer colonized lateral roots than other LGS varieties contained a higher concentration of glucosinolates than other LGS plants. Inoculated HGS plants treated with the flavonoid naringenin showed significantly more colonization than untreated HGS plants. This increase was not mediated by a naringenin-induced lowering of the glucosinolate content of HGS plant roots, nor did naringenin induce bacterial resistance to glucosinolates or increase the growth of bacteria. The erucic acid content of seed did not appear to influence colonization by azorhizobia. Frequently, leaf assays are used to study glucosinolates and plant defense; this study provides data on glucosinolates and bacterial colonization in roots and describes a bacterial reporter gene assay tailored easily to the study of ecologically important phytochemicals that influence bacterial colonization. These data also form a basis for future assessments of the benefits to oilseed rape plants of interaction with plant growth-promoting bacteria, especially diazotrophic bacteria potentially able to extend the benefits of nitrogen fixation to nonlegumes.     

Effects of Glucosinolates and Flavonoids on Colonization of the Roots of Brassica napus by Azorhizobium caulinodans ORS571

Plants of Brassica napus were assessed quantitatively for their susceptibility to lateral root crack colonization by Azorhizobium caulinodans ORS571(pXLGD4) (a rhizobial strain carrying the lacZ reporter gene) and for the concentration of glucosinolates in their roots by high-pressure liquid chromatography (HPLC). High- and low-glucosinolate-seed (HGS and LGS) varieties exhibited a relatively low and high percentage of colonized lateral roots, respectively. HPLC showed that roots of HGS plants contained a higher concentration of glucosinolates than roots of LGS plants. One LGS variety showing fewer colonized lateral roots than other LGS varieties contained a higher concentration of glucosinolates than other LGS plants. Inoculated HGS plants treated with the flavonoid naringenin showed significantly more colonization than untreated HGS plants. This increase was not mediated by a naringenin-induced lowering of the glucosinolate content of HGS plant roots, nor did naringenin induce bacterial resistance to glucosinolates or increase the growth of bacteria. The erucic acid content of seed did not appear to influence colonization by azorhizobia. Frequently, leaf assays are used to study glucosinolates and plant defense; this study provides data on glucosinolates and bacterial colonization in roots and describes a bacterial reporter gene assay tailored easily to the study of ecologically important phytochemicals that influence bacterial colonization. These data also form a basis for future assessments of the benefits to oilseed rape plants of interaction with plant growth-promoting bacteria, especially diazotrophic bacteria potentially able to extend the benefits of nitrogen fixation to nonlegumes.     

Plant growth stage effects on the feeding and growth responses of the bertha armyworm,Mamestra configurata to canola and mustard foliage

Mamestra configurata (Walker) (Lep., Noctuidae) larvae were fed excisedBrassica juncea (commercial brown mustard) orB. rapa cv. Tobin (Canola) foliage of three plant growth stages-rosette (stage 2), stem elongation (stage 3) and flowering (stage 4). Relative consumption rates (RCRi) were not significantly different between the plant species. Within theB. juncea treatments, there were no significant growth stage differences in RCRi. However, withinB. rapa, RCRi increased with advancing plant growth stage. Larvae fedB. juncea foliage had significantly reduced relative growth rates (RGRi) compared to larvae fedB. rapa foliage. Within theB. juncea treatments, RGRi decreased with advancing plant growth stage. There were no significant growth stage differences in RGRi in theB. rapa treatments. RGRi was inversely proportional to the levels of isothiocyanate-releasing glucosinolates in theB. juncea treatments. RCRi was inversely proportional to the levels of indolyl glucosinolates in theB. rapa treatments. Levels of total phenols and catechols inB. juncea did not show any trend which could be related to growth stage effects in the insect nutritional indices. InB. rapa, levels of phenols and catechols in stage 3 and 4 foliage were lower than that of stage 2 foliage. Analyses of total nitrogen in field-grown plants showed reductions in percent nitrogen from rosette to flowering stage foliage. The response ofM. configurata to different growth stages of its host plants are discussed in relation to changing levels of allelochemicals and nitrogen.     

Toxicity of hydrolysis volatile products of Brassica plants to Sclerotinia sclerotiorum,in vitro

Oilseed rape stem rot disease caused by Sclerotinia sclerotiorum causes serious yield losses worldwide. Glucosinolates as specific secondary metabolites of Brassicaceae are produced in various parts of the host plants. Their enzymatic hydrolysis releases chemical components, particularly isothiocyanates, with fungitoxic activity and volatile characteristics. To investigate the effect of volatiles derived from Brassica tissues, the pathogen was exposed to hydrolysis products of Brassica shoot parts as sources of glucosinolates including oilseed rape varieties and two species, black and white mustard. The results showed significant differences in inhibition of S. sclerotiorum growth between varieties and species. All tissues of black mustard inhibited completely the exposed colonies of the pathogen and oilseed rape varieties Dunkeld, Oscar and Rainbow had significant inhibitory effect on the fungus. The genotypes demonstrated significant differences for the production of toxic volatiles, indicating that GSL contents in Brassica species and even cultivars have different potentials for toxic products.     

Hydrolysis products of glucosinolates in Brassica napus tissues as inhibitors of seed germination

Enzymatic hydrolysis of glucosinolates, a class of compounds found in Brassica species, results in a number of products with potential to inhibit seed germination. To investigate the impact of both volatile and water-soluble allelochemicals, germination bioassays using Lactuca sativa seeds were conducted with root and combined leaf and stem tissues of Brassica napus. Tissues in which glucosinolates were hydrolyzed to remove volatile glucosinolate degradation products were compared with intact tissues and water controls. Only tissues containing glucosinolates produced volatiles that inhibited germination. Volatiles were trapped and identified using GC-MS. Volatiles produced in greater quanitity from intact tissues than from tissues without glucosinolates were almost exclusively glucosinolate hydrolysis products. Water-soluble components also inhibited germination. Chemical analysis of extracts confirmed the presence of glucosinolate hydrolysis products, but indicated the involvement of additional allelochemicals, especially in leaf and stem tissues. Results support the proposal that glucosinolate-containing plant tissues may contribute to reductions in synthetic pesticide use if weed seeds are targeted.Abbreviations ITC isothiocyanates - CN organic cyanides - OZT oxazolidinethione - iRoot intact root tissue - iL&S intact leaf and stem tissue - hRoot hydrolyzed root tissue - hL&S hydrolyzed leaf and stem tissue