Distribution of a kinesinrelated protein on Golgi apparatus of tobacco pollen tubes

The conventional kinesin and kinesin-related proteins (KRPs) constitute a large family of microtubule-based molecular motors. Members of this family bind to micro-tubules in an ATP-dependent manner. They all have microtubule-activated ATPaes activities, and play essential roles in the transport of various vesicles and organelles in eukaryotic cells[1―3]. The first plant kinesin-like protein was detected in tobacco pollen tube with an antibody against animal kinesin[4]. Recently, a number …     

烟草和元麦叶肉原生质体吸收尼古丁机制的研究

用 EA_3-867纤维素酶分离的烟草(Nicotiana tabacum)和元麦(Hordeum distichon)叶肉原生质体,分别保温在尼古丁溶液中,用紫外分光光度计测定它们对尼古丁的吸收。结果表明,这两种原生质体能迅速地吸收尼古丁;原生质体吸收尼古丁的量,随介质尼古丁浓度的升高而增多;在生理学pH范围内,介质的pH对原生质体吸收尼古丁没有多大的影响。初步认为,这两种原生质体对尼古丁的吸收是一种简单的扩散机制。     

烟草组织培养中根的分化和过氧化物同工酶及内源激素的变化

本文研究了烟草茎表皮薄细胞层、茎皮层、髓和叶四种不同外植体根的分化及过氧化物同工酶和内源IAA、ABA的变化。结果表明:上述四种不同外植体形成能力和方式有明显差异,叶的分化能力最强并可直接分化出根;茎表皮薄细胞层对光等不同的环境条件的反应最为敏感,是研究影响根分化因素的较好材料。不同浓度NaCl对组织生长及根形成影响的结果表明,1％NaCl浓度下茎皮层使停止了分化而叶仍有30％分化出根,在2％NaCl浓度下叶外植体生长与分化受到严重抑制,但转移至无NaCl的培养基上能一定程度地恢复生长和分化。根形成过程中过氧化物同工酶表现出酶带迁移、酶带数增多及酶活的变化;在不同浓度NaCl培养基上,过氧化物同工酶的酶活表现了明显的减弱。在根形成中内源IAA出现了高峰期的变化而ABA的变化表现为由低到高逐渐增加。     

In situ localization of calmodulin mRNA in the developing tobacco anthers

The temporal and spatial expression patterns of calmodulin mRNA in the developing tobacco anthers were investigated by in situ RNA hybridization, using digoxigening-labeled anti-RNA probe. Calmodulin mRNA was distributed in various developmental stages of tobacco anthers, but the expression level had temporal and spatial differences distinctly. During early stage of anther development, the expression level of calmodulin mRNA was significantly high, mainly distributed in epidermis, tapetum and transfusion parenchyma cells and so on. Especially, more mRNA was accumulated in the nuclei and chromosomes of microspore mother cells prior to and during meiosis. With the development of anther, mRNA was decreased gradually in the anther wall and pollen. By mature pollen stage, only a stronger positive reaction still existed in the epidermis of anther wall and transfusion parenchyma cells. The results suggest that the temporal and spatial expression of calmodulin mRNA is closely correlated with cell division, pollen development and substance transport.     

Apoptosis in suspension culture of tobacco cells induced by heat shock

The induction of apoptosis in suspension culture of tobacco cells by heat shock is reported for the first time. Heat treatment (48℃ for 4 h) of tobacco cells led to the appearance of typical hallmarks of apoptosis. It was demonstrated by DNA laddering analysis that the cells treated with heat shock at 48℃ for 4 h had a serious degradation of nuclear DNA into multi-nu-cleosomal sizes, suggesting that heat shock activated endogenous nuclease which led to DNA cleavage at the linkage sites between the nucleosomes, but ladders were very faint for DNA from 2 and 9 h heat-treated cells. The terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labelling (TUNEL) detection also showed that most of these treated cells (48℃ for 4 h) displayed positive reactions, indicating a serious DNA 3'-OH cleavage in their nuclei. Moreover, some other cytological changes in apoptotic cells, such as cell shrinkage, chromatin aggregation, nucleus collapse, have also been observed by 4', 6'-diamidino-2-phenyl-indole (DAPI) staining.     

RNA干扰降低烟草植株中内源生长素水平

PCR扩增利用吲哚乙酰胺水解酶基因(iaaH)全长序列,构建iaaH基因序列正、反向连接的的双元载体,通过农杆菌LBA4404介导,转化携带pTiC58 T-DNA的烟草叶片,获得携带正、反向iaaH序列的转基因植株.ELISA分析生长素的结果表明,转基因植物叶片的内源生长素含量明显降低,仅为pTiC58 T-DNA转化植株的56%,说明转基因烟草中发生iaaH基因转录后沉默,为利用该基因序列启动RNA干扰(RNAi),抑制冠瘿瘤病发生提供了实验依据.