紫露草花色形成的机理分析

运用测色法、组织切片法、电感耦合、等离子体质谱及高效液相色谱等植物成分分析方法,对单子叶植物紫露草（Tradescantia albiflora）花色形成的化学基础进行研究。结果表明,紫露草花瓣颜色属于蓝紫色系（Violet group N88B）;色素物质主要积累于近轴面和远轴面的表皮层,深度20～30 μm,且表皮细胞呈略扁平的长方形;紫露草花瓣中Ca元素含量极丰富（5 120.89 μg·g-1）,其次是Mg元素（2 360.71 μg·g-1）;主要成色色素为矢车菊素(6.671 1 mg·g-1)和飞燕草素(0.674 4 mg·g-1);主要黄酮醇类物质是山奈酚(0.327 2 mg·g-1)。本研究表明,紫露草蓝紫色花的形成可能与二价金属元素Ca、Mg与飞燕草色素及矢车菊色素螯合有关。     

若干双子叶与单子叶植物细胞壁果胶结构单糖组成特征研究

为了系统研究被子植物初生壁果胶结构单糖的组成成分及其与被子植物两纲分类的关系,结合单糖单一环式的衍生化方法,采用GC/MS测定22种被子植物初生壁果胶中单糖组分及含量,并对测得的结果进行主成分、t检验和香农 威纳指数分析。结果表明:被子植物细胞壁果胶由木糖、鼠李糖、岩藻糖、阿拉伯糖、半乳糖、葡萄糖、甘露糖7种单糖组成,其中鼠李糖、阿拉伯糖和半乳糖含量较高;岩藻糖和甘露糖含量极少。主成分分析筛选出决定22种被子植物间糖含量差异的5种果胶单糖分别为:木糖、阿拉伯糖、半乳糖、鼠李糖和葡萄糖。主成分二维图和t检验结果显示:可通过果胶单糖含量实现被子植物中双子叶和单子叶两纲植物的区分,且木糖和半乳糖决定了两纲间的显著性差异（P＜0.01）。同时香农 威纳指数结果显示了被子植物两纲在单糖含量的多样性上也存在差异,且双子叶植物的单糖多样性显著高于单子叶植物（P＜0.01）。      

双子叶植物和单子叶植物的关系

本文主要讨论了三个问趔:双子叶植物和单子叶植物胚的关系、比较和进化的关系。单子叶植物一个可能的祖先是双子叶植物的毛莨目,单子叶植物的百合目由毛莨目进化而来。双子叶型胚由于一片子叶功能的改变或面积缩小而退化或消失形成了单子叶型胚,而不是两片子叶愈合成一片子叶的结果。     

Floral flavonoids and pH in Dendrobium orchid species and hybrids

Anthocyanidins were identified in 28 Dendrobium species and hybrids selected for analysis based on colour and suitability in cut flower breeding. Flowers designated pink, red, maroon, orange, bronze, and brown in the trade were placed in RHS colour groups red-purple, purple-violet, violet on yellow, greyed-purple on yellow or yellow-orange, and brown. This colour range contained anthocyanins based on cyanidin, with peonidin occurring as a minor pigment. The colours of three blue genotypes, D. gouldii K280-6, D. biggibum ‘blue’, and D. Kultana ‘blue’, were light violet to purple by RHS standards and contained anthocyanins based on cyanidin. Peach-coloured flowers were classified as red or red-purple and included pelargonidin glycosides. Anthocyanin concentrations ranged from 0.13 to 0.18 μmoles/g FW in light lavender and peach, and up to 3.66 μmoles/g FW in brown. Combined cellular and vacuolar pH ranged narrowly from 4.67 to 5.09 among white, peach, lavender, and brown lines. Predominant copigments were flavonol glycosides based on kaempferol, quercetin, myricetin, and methylated derivatives. Flavonol aglycones and glycosylation sites differed little among two colour forms of D. gouldii and two D. Jaquelyn Thomas hybrids. Accumulation of quercetin, myricetin, and cyanidin indicated flavonoid 3' and 3',5' hydroxylation activities in several Dendrobium. Additional accumulation of isorhamnetin, syringetin, and peonidin indicated active flavonoid 3'- and 3',5'- O-methyltransferase enzymes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Towards genetic transformation in the monocot Alstroemeria L.

The successful application of plant biotechnology to Alstroemeria improvement will largely depend on the availability of an efficient regeneration/transformation system. Regeneration in Alstroemeria is accomplished from nodular embryogenic callus initiated from zygotic embryos. Histological studies of embryogenic callus initiation from 4-weeks old cultured ovules revealed that the outermost layers of the protoderm of the embryogenic nodules divided to form either a new nodule or aproembryo. Transient gene expression after particle bombardment of nodular embryogenic callus was optimized using DNA of pAHC25. The highest β-glucuronidase expression was found when the GUS gene was under control of the maize ubiquitin promoter, the target tissue was placed 5 cm below the microcarrier launch assembly and when the rupture disc-breakage point was between 650–900 psi. Kanamycin blocked regeneration of somatic embryos, however, did not block growth of nodular embryogenic callus. With phosphinothricin both callus growth and regeneration were blocked. Bombardment of nodular embryogenic callus with DNA of pAHC25 combined with selection on medium containing phosphinothricin resulted in putative transgenic chimeric. Friable calli were selected from nodular embryogenic callus and used to initiate suspensions. These cell suspensions were subjected to transformation by particle bombardment using DNA of pAHC25 and resulted in a stable transformed friable callus line after selection based on luciferase activity. Even after 2 years of maintenance this callus line was luciferase positive and the Polymerase Chain Reaction analysis demonstrated the presence of the introduced gene in this friable callus line. This revised version was published online in July 2006 with corrections to the Cover Date.