环境胁迫和激素诱导甘蔗ACC合成酶基因家族三个成员的表达

ACC合成酶（ACS）是高等植物乙烯生物合成途径中的限速酶。在克隆到甘蔗ACC合成酶基因家族3个成员Sc-ACS1、Sc-ACS2和Sc-ACS3的基础上，分别以它们作为探针，检测了激素诱导和环境胁迫对甘蔗苗期该3成员表达的影响。结果表明，乙烯利诱导Sc-ACS1在叶中表达，在根中不表达；Sc-ACS2在根、叶中表达；Sc-ACS3主要在根部表达，在叶中不表达。在甘蔗叶片中，Sc-ACS1对冷胁迫、暗培养和LiCl胁迫均有应答，并受植物生长激素IAA诱导而表达；Sc-ACS2无论是在生长激素诱导还是环境胁迫下，其mRNA均维持较低水平。     

Field evaluation of antisense RNA mediated inhibition of GBSS gene expression in potato

Summary Granule-bound starch synthase (GBSS) catalyses the synthesis of amylose in starch granules. Analysis of antisense RNA mediated inhibition of GBSS gene expression in large numbers of tubers from in vitro grown, greenhouse grown and field grown transgenic potato plants revealed stable and total inhibition of GBSS gene expression in one clone. In three other transgenic genotypes partial and unstable inhibition was found. In these genotypes both GBSS activity and amylose content were remarkably reduced compared with the non-transformed control genotype. No relationship was found between the level of inhibition of GBSS gene expression and yield and dry matter content.     

Effect of genotype,environment and carbohydrate on anther culture response in head cabbage (Brassica oleracea L. convar. capitata (L.) Alef.)

Summary The effect of genotype, growing conditions for donor plants and type and concentration of carbohydrate in the culture medium was investigated for anther culture of head cabbage (white cabbage, savoy cabbage, pointed-headed cabbage). Strong genotypic effects on embryo formation from the cultured anthers were shown as well as superior embryo formation from anthers of field grown donor plants compared to plants grown in the greenhouse. When comparing 7, 10 and 13% sucrose in the medium, embryo response increased with increasing sucrose concentration. With maltose, which was generally inferior to sucrose as carbohydrate source for anther culture, the embryo response did not increase with maltose concentration above 10 per cent.     

Developing gene-tagged molecular markers for functional analysis of starch-synthesizing genes in rice (Oryza sativa L.)

The granule-bound starch synthase(GBSS), starch branching enzymes 1 (SBE1)and 3 (SBE3) are major enzymes involved in starch biosynthesis in rice endosperm. Available sequences of Sbe1 and Sbe3 genes encoding corresponding SBE1 and SBE3 have been used to identify homologous regions from genome databases of both the indica rice 93-11 and the japonica rice Nipponbare. Sequence diversities were exploited to develop gene-tagged markers to distinguish an indica allele from a japonica allele for both Sbe1 and Sbe3 loci. With these newly developed gene-tagged markers and available Wx gene markers, the roles of these starch-synthesizing genes (Sbe1, Sbe3, and Wx) in determining amylose content (AC) in the rice endosperm were evaluated using a double-haploid (DH)population derived from a cross between the indica rice cv. Nanjing11 and the japonica rice cv. Balilla. Only the Wx and Sbe3 loci had significant effects on the AC variation. On average, indica Wx ^a genotypes showed ∼9.1% higher AC than japonica Wx ^b genotypes, while indica Sbe3 ^a genotypes showed ∼1.0% lower AC than japonica Sbe3 ^b genotypes. A significant interaction was also observed between Wx and Sbe3 loci whereby the amylose content was 0.3% higher in Sbe3 ^a than Sbe3 ^b genotypes in the presence of the Wx ^a allele, but it was lower by 2.3% in the presence of the Wx ^b allele. Overall, polymorphisms at the Wx and Sbe3 loci together could account for 79.1% of the observed AC variation in the DH population. The use of gene-tagged markers in marker-assisted selection and gene functional analysis was also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effectiveness of selection for quality traits during the early stage in the potato breeding population

Potato cultivars resistant to cold‐temperature sweetening are of major importance to the processing industry producing both chips (crisps) and French fries. When most modern potato cultivars are maintained in cold storage to retard sprouting, the tubers accumulate reducing sugars, and the products become an unacceptable brown colour when fried. Selection for better processing quality during the early generations of a breeding programme could be of considerable advantage. Using a portable ‘sugarmeter’, which requires only a drop of sap from the tuber on a test strip, many samples can be efficiently surveyed for low sugar as early as the F₁ generation. Using seedlings of three test crosses, glucose and specific gravity of field‐grown tubers, minitubers from greenhouses and microtubers from in vitro culture were compared after cold treatment. Although the mean glucose levels of minitubers and microtubers were higher than field‐grown tubers, the correlation between the glucose contents of the three types of tubers was fairly high. A considerable genetic improvement was noted when progenies were grown as minitubers or microtubers, even though the response to selection for low glucose levels in minitubers and microtubers was lower than from direct selection from field‐grown tubers. The specific gravity of field‐grown tubers showed a significant association with freshly harvested minitubers and microtubers. Selection for low glucose content in minitubers can therefore save considerable resources in a breeding programme.     

旱种水稻结实期茎中碳同化物的运转及其生理机制

以杂交水稻汕优63和籼稻扬稻6号为材料，研究了旱种(地膜覆盖栽培)水稻结实期茎中碳同化物的运转及其生理机制。结果表明，抽穗至成熟期旱种水稻标记14C从茎中向籽粒的再分配、茎中非结构性碳水化合物(NSC)的运转率及其对籽粒的贡献率均显著高于水种(常规栽培)水稻。水稻旱种后籽粒中的蔗糖合成酶和酸性转化酶活性、茎中α-淀     

玉米颗粒结合型淀粉合成酶(GBSS )基因cDNA的克隆及植物表达载体的构建

根据已发表的玉米颗粒结合型淀粉合成酶GBSS（granule-bound starch synthase）基因序列,设计两对引物,其中一对为定点突变的过度引物。从授粉后15d的玉米胚乳中提取总RNA,以反转录合成的cDNA第一链为模板,首次用定点突变、RT-PCR、融合PCR的方法克隆了GBSS 基因的全长cDNA（1818bp）片段。序列测定表明,该片段与文献报道的序列具有99.72％的同源性。并构建了以胚乳特异表达性的Gt1为启动子,以NOS-ter为终止子的植物表达载体pBI-Gt1-GBSS,其含有NPT‖选择标记基因。以期实现特定时期GBSS基因在玉米胚乳中的大量表达。     

白藜芦醇合成酶(RS)基因转化胡萝卜及高白藜芦醇转基因胡萝卜株系的筛选

白藜芦醇是具有抗病及多种保健功能的芪类次生代谢物,胡萝卜(Daucus carota var.sativa)则是富含β胡萝卜素等多种营养成分的重要蔬菜。研究着眼于创建具有白藜芦醇保健功能的胡萝卜新种质资源,在对葡萄(Vitis vinifera L.)白藜芦醇合成酶(resveratrol synthase,RS)基因在胡萝卜中高效表达的密码子优化基础上构建无潮霉素磷酸转移酶(HPT)抗性基因的转化载体pCB-RS-hyg-,应用根癌农杆菌(Agrobacterium tumefaciens)介导法将pCB和pCB-RS-hyg-共转化到胡萝卜并获得再生植株。经过T0、T1和T2代的逐代筛选,获得2个白藜芦醇含量较高(11.34和15.23mg/g)的转基因胡萝卜株系。     

糖基天然表面活性剂蔗糖酯的研究综述

综述了非离子糖基天然表面活性剂蔗糖酯的各种合成方法:酰氯酯化法、酯交换法、酶催化法等.重点介绍了现有的较成熟的酯交换法的各种工艺,包括溶剂法,水溶剂法和无溶剂法,并介绍了不同合成方法相应的精制工艺和检测方法,指出了现有各种工艺的优点和缺陷,并展望了我国蔗糖酯工业发展的趋势.     

甘蔗增糖增产剂试验结果

１９９３年９月下旬至１０月中旬，采用广西农业大学研制、生产的甘蔗增糖增产剂在对旱地和水田蔗的５个品种进行试验，喷药后４０～９０ｄ测定１３个点的甘蔗蔗糖分，平均比对照提高１．３０％（绝对值），甘蔗产量增加５８５０ｋｇ／ｈｍ２；８月份和９月份追施氮肥的甘蔗增糖增产较显著，甘蔗蔗糖分提高１．６９％（绝对值），增产１０３５１．５ｋｇ／ｈｍ２；８月份和９月份不追肥的甘蔗．喷施增糖增产剂的效果相对较差。平均来说，糖厂增利２５８２．２５元／ｈｍ２，农民增收８１９元／ｈｍ２。