荞麦中苯丙氨酸解氨酶活力与黄酮含量的关系

荞麦幼苗及幼苗不同器官中黄酮含量随着苯丙氨酸解氨酶（PAL）活力变化而变化。X射线处理可增强荞麦幼苗中苯丙烷类代谢途径，致使黄酮含量提高。由此推测，苯丙氨酸解氨酶活力与黄酮类次生物质的形成具有密切关系。

粘红酵母产L-苯丙氨酸解氨酶的研究

对粘红酵母 (Rhodotorula glutinis)产生 L -苯丙氨酸解氨酶 (PAL )的产酶条件进行了研究。结果表明粘红酵母产酶最佳条件为 :培养基 /g· L- 1 ;葡萄糖 5 .0 ,豆饼水解液 10 .0 (以氨基酸计 ) ,KH2 PO40 .5 ,p H5 .5 ;接种量 5 % ,摇瓶转速 170 r/min,2 8℃培养 15 h后添加 L -苯丙氨酸至终质量浓度 0 .5 g· L- 1 ,继续培养至 2 1h。酶比活力较以前提高了 10 m

井冈霉素A对水稻纹枯病菌的毒力和作用机理研究

根据水稻纹枯病菌 Rhizoctonia solani AG- 1IA在含系列浓度井冈霉素 A马铃薯葡萄糖琼脂培养基 (PDA)上的菌丝生长速率 ,计算出药剂的毒力回归方程为 :Y=3.2 30 9+0 .872 0 X,r=0 .9910 ,药剂的 EC50 =10 6 .9μg/ m L,EC75=6 34.5 μg/ m L。在含 5 0 0 μg/ m L井冈霉素 A的 PDA上水稻纹枯病菌的菌丝生长抑制率为 74 .1% ,而田间水稻植株上人工接菌的药效试验结果表明 ,5 0 μg/ m L药液喷洒后 7d和 14 d的防效即可分别达到 77.4 %和 76 .7% ,即药剂在 PDA平板上的理论抑制作用仅是田间活体植株上对病菌实际作用效果的 1/ 10。比较室内毒力和田间药效试验的结果可以看出 ,井冈霉素 A具有对病原菌和寄主植物双重作用的特性。研究首次发现 ,在室内培养基上不能有效抑制病菌生长的 1μg/ m L的井冈霉素 A可以在水稻植株未喷药部位产生防御水稻纹枯病的作用 ,且能够持续诱导植物防御反应相关酶——过氧化物酶 (PO)和苯丙氨酸解氨酶 (PAL)的活性增高 ,表明该药剂可以激发水稻抗性防卫反应的表达。

Germination Characteristics and Secondary Metabolism Regulation of Scutellaria baicalensis Georgi Seeds under Different Temperatures

[Objective] To study the germination characteristics and secondary metabolism of Scutellaria baicalensis Georgi seeds under different temperatures.[Method]The activities of superoxide dismutase（SOD）and peroxidase（POD）were determined with lactoflavine-NBT method and guaiacol-colorimetry assay,respectively.The catalase（CAT）,ascorbate peroxidase（APX）,phenylalanine ammonia-lyase（PAL）and cinnamic acid 4-Hydroxylase（C4H）were determined with ultraviolet spectrophotometry.The secondary metabolites were detected by High Performance Liquid Chromatography（HPLC）.[Result]The germination percentage,germination potentiality and germination index were seriously affected by low or high temperature.The proper germination temperature was 20-25 ℃.The activities of SOD,POD and CAT were significantly decreased as comparison to suitable temperature.The activities of PAL and C4H were also significantly decreased as comparision to suitable temperature which was accordance to the secondary metabolites.There was a positive correlation between the flavonoids content and the PAL and C4H activity（r=0.956,r=0.951,P0.05）.[Conclusion]The quality of the skullcaps could be improved by improving the activity of PAL and C4H.The proper temperature for the seed germination and the formation of secondary metabolites was 20 ℃.

Germination Characteristics and Secondary Metabolism Regulation of Scutellaria baicalensis Georgi Seeds under Different Light Intensities

[Objective] This study aimed to investigate the primary and secondary metabolisms during the germination of Scutellaria baicalensis Georgi seeds under different light intensities. [Method] The activities of CHL, soluble sugar, PAL, C4H and CHS were determined with ultraviolet spectrophotometry. The secondary metabolites were detected by High Performance Liquid Chromatography （HPLC）. [Result] The results indicate that the germination of Scutellaria baicalensis Georgi seeds is not sensitive to light and the seedlings were very sensitive to light. The CHL, soluble sugar, PAL, C4H and CHS continuously increased with light intensity. The content of secondary metabolites also increased. [Conclusion] Light increased the formation of leaf photosynthetic pigment, thereby affecting the primary metabolites. The activities of PAL, C4H and CHS significantly increased with the development of light intensity. Finally the secondary metabolites of medicinal plants increased sharply. Therefore, the quality of Scutellaria baicalensis Georgi materials can be improved by increasing the light intensity moderately.

Activities of lipoxygenase and phenylalanine ammonia lyase in poplar leaves induced by insect herbivory and volatiles

A study was conducted to explore the defense response in woody plants after insect herbivory. The activities of two enzymes, lipoxygenase （LOX）, a key enzyme ofjasmonate （JA） pathway, and phenylalanine ammonia lyase （PAL）, a rate-limiting enzyme of phenyl- propanoid pathway, were measured in the leaves of one-year-old poplar （Populus simonii × P. pyramidalis ＇Opera 8277＇） cuttings after Clostera anachoreta larvae attack. The results show that the increased activities of LOX and PAL were found not only in the leaves wounded by C. anachoreta larvae but also in their tipper systemic leaves, indicating that JA and phenylpropanoid pathways were activated, and the defense response was stimulated systemically. The increase in LOX and PAL activities in neighboring intact poplar cuttings sug- gested that there exists the interplant communication between poplar plants mediated by the herbivore-induced volatiles. Methyl jasmonate （MeJA） was also proved to be an airborne signal to induce defense response in P simonii × P pyramidalis ＇Opera 8277＇ cuttings.

Changes of Primary and Secondary Metabolism during the Seed Germination of Scutellaria baicalensis Georgi

[Objective] To investigate the primary and secondary metabolism during the seed germination of Scutellaria baicalensis Georgi. [Method] The activities of SOD and POD were determined with lactoflavine-NBT method and guaiacol-colorimetry as- say, respectively. The activities of CAT, APX,PAL and C4H were determined with ultraviolet spectrophotometry. The contents of secondary metabolites were detected by High-performance Liquid Chromatography （HPLC）. [Result] The results indicate that the soluble sugar content decreased during the first 5 days and then increased when the cotyledons formed. The contents of PAL, C4H and CHS continuously in- creased at different stages during the seed germination process. The secondary metabolites also showed the consistent variation trend. In addition, the contents of secondary metabolites had significant positive correlation with the key enzyme activi- ty. [Conclusion] The formation of secondary metabolites is significantly positively cor- related with the key enzyme during the seed germination process. Therefore, the key enzyme activity can be enhanced by adopting appropriate measures to improve the secondary metabolites, thereby obtaining high-quality medicinal materials.

Germination Characteristics and Secondary Metabolism Regulation of Scutellaria baicalensis Georgi under Different Illumination Time

This study aimed to investigate the primary and secondary metabolism of Scutel aria baicalensis Georgi during seed germination process under different il umination time. [Method] Chlorophyl （CHL） content, soluble sugar content, phenylalanine ammonia lyase （PAL） activity and cinnamate-4-hydroxylase （C4H） ac-tivity were determined with ultraviolet spectrophotometry. The secondary metabolites were detected by high performance liquid chromatography （HPLC）. [Result] The re-sults indicated that the germination of S. baicalensis seeds was not sensitive to light and the seedlings were very sensitive to light. CHL content, soluble sugar content, PAL activity and C4H activity increased continuously with the il umination time. The secondary metabolites showed a similar trend. [Conclusion] Il umination time promoted the formation of leaf photosynthetic pigments, thereby affecting the synthesis of primary and secondary metabolites and the activities of PAL and C4H. Therefore, the quality of S. baicalensis can be improved by regulating the il umina-tion time appropriately.

Cloning, Expression and Analysis of pal, a Positive Gene Involved in Capsaicin Biosynthesis in Capsicum chinense Jacq

The cDNA sequence of Capal gene was cloned from Capsicum chinense Jacq by RT-PCR and sequenced. Bioinformatics analysis showed that Capal en- codes a putative polypeptide of 683 amino acids with a calculated molecular mass of 74.2 kD and a theoretical pl of 6.9. Multiple sequence alignments and phyloge- netic tree analyses showed that Capal protein of C. chinense is similar to that of Capsicum annuum var. conoides, with an overall sequence similarity of 96%. The prokaryotic expression vector pET-32a-pal was constructed and induced to express in E. coil BL21. The SDS-PAGE analysis showed that the relative molecular mass of the induced new protein is about 74 kD, which was basically identical with that predicted by DNAMAN software （74.3 kD）, Real-time PCR analysis showed that ex- ogenous jasmonic acid （JA） promoted pal expression. The accumulation of capsaicin in pepper was analyzed by high performance liquid chromatography （HPLC）, and the results indicated that exogenous jasmonic acid （JA） can promote the synthesis of capsaicin. This study will provide valuable experimental basis for the research of transcription regulation and explaining the gene function of pal.