白肋烟烟碱转化及烟草特有亚硝胺形成

从烟草特有亚硝胺形成的化学,烟草特有亚硝胺与前体物的关系,调制过程、贮藏过程中烟草特有亚硝胺的形成,遗传改良降低烟碱转化和烟草特有亚硝胺,生物技术抑制烟碱转化降低烟草特有亚硝胺等方面综述了最新研究进展.     

白肋烟生物碱和烟碱转化率的配合力及遗传力的研究

采用Grimng双列杂交第二种设计方法，对4份不同烟碱转化率的白肋烟株系及杂交F1代进行了烟碱、降烟碱和烟碱转化率的杂交配合力和有关遗传参数的研究。结果表明，烟碱、降烟碱和烟碱转化率的表现型方差主要是遗传基因型方差决定的，遗传方差中亲本的一般配合力效应方差和基因加性方差对烟碱转化率的作用最大，在特殊组合中也存在一定的特殊配合力和基因非加性效应。环境方差除对烟碱有一定影响外，对降烟碱和烟碱转化率影响极小。非转化株系亲本的一般配合力效应和非转化株系间的杂交F1特殊配合力效应，在降烟碱和烟碱转化率性状上表现为负向，烟碱为正向；高转化株系则相反。因此，在白肋烟低烟碱转化率育种中选择非转化亲本尤为关键。降烟碱和烟碱转化率为高遗传力性状，对杂交后代进行早世代生物碱和烟碱转化率严格选择是十分必要的。     

二次调配烟用香精的稳定性研究

采用溶剂萃取结合GC/MS分析了不同保存期的二次调配烟用香精的香味成分,并运用主成分分析(PCA)法和t检验法分析了香精组分的变化。结果表明:二氯甲烷萃取能最大程度地提取香精的成分,且具有较好的重复性。用PCA和t检验法处理不同保存期烟用香精的GC/MS分析数据,可了解不同存放期香精样品整体变化特征及组分含量的显著性变化情况,为二次调配烟用香精样品的稳定性及存放期提供参考。     

HPLC-MS/MS法测定家兔血液中的NNN及其代谢物

为了准确测定家兔血液中的N-亚硝基降烟碱(NNN)及其代谢物,通过对色谱、质谱条件的优化和选择,建立了以NNN-d4为内标,通过沉淀蛋白的前处理操作以及Waters亲水相互作用色谱(HILIC)柱分离和多离子反应监测模式(MRM)测定大耳朵白兔血浆中NNN及其代谢物的HPLC-MS/MS方法。结果表明,NNN及其代谢物的相对标准偏差(RSD)、回收率和检测限分别为0.50%~8.62%,80%~111%和0.039~0.217 ng/mL。该方法简单、快速灵敏,适合于血液中NNN及其代谢物的检测。     

Mechanism of damage-induced alkaloid production in wild tobacco

Greenhouse-grown tobacco plants of the speciesNicotiana sylvestris (Solanaceae) subjected to leaf damage show a fourfold increase in the alkaloid content of their undamaged leaves. This increase in nicotine and nornicotine concentrations begins 19 hr after the end of the damage regime, reaches a maximum at nine days, and wanes to control levels 14 days after the start of leaf damage. The increase in leaf alkaloid content in damaged plants is largely due to a 10-fold increase in the alkaloid concentration of the xylem fluid entering leaves, which, in turn, suggests that increased synthesis of alkaloids is occurring in the roots. This research distinguishes between positive and negative cues affecting the change in xylem fluid alkaloid concentrations. A negative cue, such as auxin, when lost or diminished as a result of leaf damage could signal the alkaloidal response. Indeed, exogenous applications of auxin to damaged leaves inhibit the alkaloidal response. However, attempts to block endogenous auxin transport by steam girdling or applying an auxin transport inhibitor fail to mimic the effect of leaf damage on leaf alkaloid concentrations. The damage cue appears to be a positive cue that is related to the timing and the amount of leaf damage rather than to the amount of leaf mass lost. Moreover, when performed proximally to leaf damage, steam girdling truncates the alkaloidal response. This induced alkaloidal response appears to be triggered by a phloem-borne cue that allows the plant to distinguish between different types of leaf damage. The physiological and ecological consequences of the mechanism of this damage-induced alkaloidal response are further explored.     

烤烟中的烟碱和去甲基烟碱

综述了国内外有关烤烟生长期烟碱、去甲基烟碱形成及相互转化关系的研究结果.烟碱、去甲基烟碱的形成受品种、自然条件和栽培措施等的影响;烟碱、去甲基烟碱之间的转化受多种酶调控,其中甲基化酶和去甲基酶起关键作用.     

白肋烟不同程度烟碱转化株后代烟碱转化率株间变异研究

采用烟碱转化早期诱导方法,对白肋烟达所26及其自交后代不同烟株的烟碱转化率进行了分析测定,以确定烟碱转化株鉴别标准的可靠性和有效性.结果表明,烟碱转化率低于2.5％的烟株自交后代株系稳定,株间烟碱转化率变异小,且均低于2.5％,表明母代烟株为非转化株;烟碱转化率介于2.5％和3％的3个烟株自交后代均表现株间烟碱转化性状的分离,变异幅度分别为0.439％-10.331％、0.466％-21.834％和0.394％-3.757％,表明母代烟株为转化株.烟碱转化率大于3％的烟株自交后代烟碱转化率株间变异性大,烟碱转化性状分离严重;烟碱转化率大于50％的2个烟株自交后代烟碱转化率也都较高,是高转化株的表现.因此,烟碱转化率大于2.5％是确定转化株的可靠标准.     

Alkaloidal responses to damage inNicotiana native to North America

We performed field tests of alkaloid induction inNicotiana attenuata plants growing in southwestern Utah with mimicry of the two major types of damage inflicted by invertebrate and vertebrate herbivores: leaf damage and stalk removal, respectively. In undamaged plants, seasonal increases in leaf nicotine content occurred at a rate of 0.046% leaf dry mass/day. Leaf damage doubled the accumulation rate to 0.086–0.138% leaf dry mass/day, while stalk removal resulted in a quadrupling of the accumulation rate to 0.206% leaf dry mass/day. These damage-induced increases in nicotine accumulation are significantly larger than between-plant and phenological variations. Leaf damage to the nornicotine-(N. repanda andN. trigonophylla) and anabasine-accumulating (N. glauca)Nicotiana species native to North America resulted in 1.5- to 5-fold increases in their principal leaf alkaloid pools. We conclude that alkaloid induction is not limited to nicotine-accumulatingNicotiana species and that herbivores feeding on previously damaged plants are likely to encounter tissues with alkaloid titers significantly higher than those of undamaged plants.     

高效液相色谱同时检测不同类型烟叶中的多种生物碱含量

为快捷准确地测定烟叶中生物碱的含量,本研究通过优化提取条件,建立了测定烟草中烟碱、新烟草碱、假木贼碱和降烟碱的高效液相色谱检测方法。优化后的检测步骤为：干烟叶和5%甲醇的料液比为100 mg/20 mL,在25℃下振荡提取30 min,色谱条件：C18柱（250 mm×4.6 mm,5 μm）,流动相A（90%水+10%甲醇,pH 6.8,0.15%醋酸钠）,流动相B（90%甲醇+10%水,pH 3.8）。烟碱在0.1~50 μg/mL、其余3种在0.005~2μg/mL的范围内,4种生物碱均具有较好的线性关系（R²>0.99）;烟碱检出限为0.000 65 μg/mL,平均回收率100.79%,RSD 3.11%;新烟草碱检出限0.088 4 μg/mL,平均回收率98.53%,RSD 3.75%;假木贼碱检出限0.034 8μg/mL,平均回收率98.70%,RSD 3.63%;降烟碱检出限0.150 9 μg/mL,平均回收率101.33%,RSD 4.61%。对4种不同类型烟叶共11个不同样品进行检测验证,检测结果可靠。该方法前处理简单快捷,灵敏度高,重复性较好,可以满足烟草样品中4种生物碱的检测要求。     

我国不同类型烟叶烟碱转化株的比例和转化程度分布

为进一步纯化烟叶群体,提高烟叶品质。对我国5种类型(烤烟、白肋烟、香料烟、马里兰烟和晒红烟)13个主栽品种的烟叶(2003-2004年调制)烟碱转化株的比例和转化程度分布进行了分析测定。白肋烟品种和杂交种存在严重的烟碱向降烟碱转化问题,总转化株占烟株群体的比例除B37外,均在30%以上;烤烟品种烟碱转化问题相对较小,转化株比例低,且多为低转化株,所测品种群体中总转化株的比例不超过7%;香料烟和马里兰烟群体总转化株比例也偏高,分别为10.0%和9.84%,而且有一定比例的高转化株;晒红烟转化株比例较低。