Comparison of Absorption Capacity of Different Flue-cured Tobacco Cultivars for Six Kinds of Heavy Metals

[Objective] This study aimed to analyze the differences in absorption capacity of different flue-cured tobacco cultivars for chromium （Cr）, arsenic （As）, cadmium （Cd）, lead （Pb）, mercury （Hg） and copper （Cu）. [Method] With 4 flue-cured tobacco cultivars as the experimental materials, their absorption capacity for 6 kinds of heavy metals was compared by pot experiment. [Result] There were great differences in absorption capacity of different flue-cured tobacco cultivars for the six kinds of heavy metals. According to the absorption capacity of different flue-cured tobacco cultivars for the heavy metals, the six heavy metals could be classified into three categories. The first category included only Cd with average enrichment coefficient of 8.564; the second category included Hg with average enrichment coefficient of 0.753; and the third category included Cr, As, Pb and Cu with average enrichment coefficients below or equivalent to 0.114. [Conclusion] The absorption capacity of different flue-cured tobacco cultivars for heavy metals was grasped by this study, thereby providing reference data for screening of high-yielding and high-quality flue-cured tobacco cultivars.

Uptake and Subcellular Distribution of Cd in Tobacco

In this study,tobacco cultivar Nanjiang No.3 was selected as the experimental material to uptake,accumulation and subcellular distribution of Cd in tobacco.The results showed that Cd uptake in tobacco leaves increased first then declined and increased again;the content generally in descending order of of Cd in various subcellular fractions of tobacco leaves demonstrated a descending order of cytosols〉cell walls〉mitochondria〉chloroplasts;the contents of Cd in various subcellular fractions of tobacco roots were in an descending order of cell walls〉cytosols〉mitochondria〉chloroplasts;under high Cd concentrations,tobacco plants were seriously harmed by Cd.This study provided theoretical basis for the improvement of tobacco production.

The Effects of Climate,Soil and Cultivar on the Content of Surface Trichome Exudates from Fresh Flue-cured Leaves

[Objective] The aim was to study the effect of climate and soil on the content of surface trichome exudates from fresh flue-cured leaves. [Method] The experiment was conducted in 2009 in Longgang, Weining and Tianzhu of Guizhou Province with flue-cured tobacco variety Yun 85. Mature tobacco leaves were taken from lower, middle and upper plant positions respectively and major cuticular com-ponents of the leaves were extracted with methylene chloride and their chemical compositions were analyzed with GC-MS. [Result] The result showed that there was large difference among trichome exudates of leaves grown under different climatic conditions. The leaf trichome exudates from Tianzhu were quite higher than those from Weining and Longgang, and trichome exudates difference between Tianzhu and Longgang was significant. Soil conditions had considerable effect on the content of tobacco leaf surface trichome exudates, leaf from Longgang soil had highest con-tent, fol owed by Tianzhu soil leaf, Weining soil leaf had lowest content. Under vari-ous climatic conditions, the contents of leaf trichome exudates of same soil were in-consistent, indicating the presence of certain climate and soil factor interaction; The contents of leaf trichome exudates from four cultivars in Longgang showed large difference, Nanjiang 3 was the lowest, fol owed by K326, Guiyan 201 was high, and Yunyan85 the highest. The content of leaf trichome exudates of Yunyan85 was more than two times of that of Nanjiang 3. [Conclusion] The Effect of climate factor on the content of leaf trichome exudates was greater than that of cultivar, which was then larger than soil condition.

Cloning and characterization of a novel UDP-glycosyltransferase gene induced by DON from wheat

Fusarium head blight（FHB）,caused primarily by Fusarium graminearum,is a destructive disease of wheat throughout the world.However,the mechanisms of host resistance to FHB are still largely unclear.Deoxynivalenol（DON）produced by F graminearum which enhances the pathogen to spread could be converted into inactive form D3 G by UDP-glycosyltransferases（UGTs）.A DON responsive UGT gene,designated as TaUGT4,was first cloned from wheat in this study.The putative open reading frame（ORF） of TaUGT4 was 1386 bp,encoding 461 amino acids protein.TaUGT4 was placed on chromosome 2D using a set of nulli-tetrasomic lines of wheat cultivar Chinese Spring（CS）.When fused with eGFP at C terminal,TaUGT4 was shown to localize in cytoplasm of the transformed tobacco cells.The transcriptional analysis revealed that TaUGT4 was strongly induced by F graminearum or DON in both of FHB-resistant cultivar Sumai 3 and susceptible cultivar Kenong 199,especially in Sumai 3 under DON treatment.Similar increase of TaUGT4 expression was observed in Sumai 3 and Kenong 199 in response to salicylic acid（SA） treatment.But interestingly,the transcripts level of TaUGT4 in Sumai 3 showed significantly higher than that in Kenong 199 after treated with methyl jasmonate（MeJA）.According to the expression patterns,TaUGT4 might lead to different effects between FHB-resistant genotype and susceptible genotype in the process against F graminearum inoculation.It had also been discussed in this paper that JA signaling pathway might play a significant role in the resistance against F.graminearum compared to SA signaling pathway.