广州地区SCMV玉米分离物外壳蛋白基因的序列分析及其引致的生理病变

外壳蛋白(CP)基因序列分析结果表明,广州地区甜玉米上的甘蔗花叶病毒(SCMV)分离物属于玉米变异组,与我国其他地区玉米上的SCMV分离物有较大差异。其CP基因核苷酸同一率与广东甜玉米分离物(AJ310105)为91.6%,而与我国其他地区玉米分离物同一率为85.1%-87.1%。通过对该分离物侵染甜玉米所致的细胞病变进行超薄切片电镜观察,结果表明,除多种细胞器病变外,还有4种类型的内含体,即风轮体、卷筒体、束状体和片层集聚体,部分束状体与胞间连丝相连,可能与病毒胞间运转有关。该分离物机械摩擦接种侵染甜玉米后,引致寄主植物叶组织PAL和SOD酶活性较大的变化,其中PAL活性在侵染早期比对照低,随后比对照高,SOD活性比对照稍高,而POD和CAT酶活则与对照无显著差异。     

甘蓝型油菜种皮黑色素形成机理的研究

甘蓝型油菜在种子发育过程中种皮中黑色素含量与多酚和游离酪氨酸呈极显著或显著负相关. 提纯后黑色素的HPLC分析结果表明黑籽和黄籽油菜种皮黑色素的组成相同. 在种子发育后期, 种皮黑色素的增加速率(0.255)与游离酪氨酸(0.071)和多酚(0.208)含量的下降速率之和(0.279)相近, 说明黑籽油菜中黑色素是以游离酪氨酸和多酚为前体     

Ultrastructure of Seed Coat Development in the Natural Tetraploid Trifolium pratense L.

Seed coat development in the natural tetraploid Trifolium pratense L. was studied by electron microscopy. The mature seed coat derived from the outer integument is composed of three layers of cells. The cells of the outer epidermis divide anticlinally and undergo radial elongation to form a macrosclereid layer. The cells are characterized by thin walls, the presence of amyloplasts, and numerous vacuoles which are completely or incompletely filled with tannin. The outer tangential walls are thickened at an early stage. An electron-translucent cap develops in the outer tangential walls of the macrosclereid cells at the globular embryo stage. Osteosclereid cells are highly vacuolate with densely staining cytoplasm. Gradually, extensive intercellular spaces are formed. The parenchyma cells are small and have prominent intercellular air spaces. Maturation eventually leads to the disappearance of cytoplasm in all cells, and the compression of the cells of the parenchyma layer.     

Characterization of a New Nepovirus Infecting Apricot in Southeastern France: Apricot Latent Ringspot Virus

A pathogen was transmitted from apricot trees showing symptoms of viral infection to GF305 peach seedlings which reacted by stunting, shortened internodes and chlorotic mottling. The agent was transmitted to cherry, apricot, peach and plum by grafting and to several herbaceous hosts by mechanical inoculation. Isometric nepovirus-like particles of 30–31 nm diameter extracted from infected Chenopodium quinoa sedimented as two peaks in sucrose gradients. These particles contained two single stranded RNAs of approximately 5.9 and 7.9 kb, and a single coat protein subunit of 53.7 kDa. No cross-reactions were observed with a number of nepoviruses infecting fruit trees. Inoculation of purified particles to herbaceous or woody hosts reproduced the same symptoms caused by the original isolate. Sequencing of a 2.2 kbp cDNA clone covering the 3 end of the small genomic RNA identified an open reading frame encoding a 317 aa N-truncated protein exhibiting significant similarities with the coat protein of nepoviruses. The 1257 nt long 3 non-coding region showed up to about 65% homology to the equivalent region of members of the subgroup C of nepoviruses. The properties of this pathogen do not match those of any previously described nepovirus. It should therefore be considered as a new member of the subgroup C of nepoviruses, for which the name of Apricot latent ringspot virus (ALRSV) is proposed.The nucleotide sequence reported in this work has been deposited in the EMBL databank under the accession number AJ278875.     

克鲁兹王莲种子发芽特性及其促进萌发的初步研究

王莲是热带水生植物，其发芽特性不同于一般的植物。该文着重探讨了克鲁兹王莲种子发芽特性及促进种子萌发的途径。通过光照处理，种皮处理及乙稀利处理和低温保存等一系列试验，说明了种皮不是影响王莲发芽的主要因素，光照、乙稀利及低温保存是促进王莲种子发芽的有利因素，三者具有互为增补效应。生理后熟期的完成与否可能是萌发的关键所在。     

抗PRSV转基因番木瓜研究进展

番木瓜花叶环斑病毒（PRSV）严重影响着热带亚热带的重要水果番木瓜的生产,在物理和化学防治措施效果不佳的情况下,利用病原获得抗性防治PRSV的方法给番木瓜的生产带来一线生机。综述了近年来转基因番木瓜中所采用的PRSV病毒的几个基因及其优缺点。     

芥甘杂交选育甘蓝型黄籽油菜的研究

甘蓝型黄籽油菜育种是当前油菜育种的一个主要研究方向,但甘蓝型油菜中缺乏黄籽基因资源.利用芥菜型黄籽地方品种四川黄籽作为基因供体,与甘蓝型双低油菜品种进行种间杂交,在BC1F2代发现黄籽单株,经过3个世代的自交纯化,已获得高油分、双低或单低的黄籽甘蓝型油菜新种质.     

6株鱼类病毒性神经坏死病病毒cp基因的分子特征和遗传发生分析

根据已报道的鱼类病毒性神经坏死病毒(viral nervous necrosis virus, VNNV)衣壳蛋白基因(coat protein gene, cp基因)设计引物,对2006年从我国沿海养殖石斑鱼中分离到的6株鱼类神经坏死病毒进行RTPCR扩增,特异性扩增出6株病毒的完整衣壳蛋白基因,分别连接到pMD18-T载体中,并进行序列测定和分析.结果发现,6个VNNV分离株的cp基因核苷酸序列的同源性在97.3%以上;推导的氨基酸序列同源性在79.6%～99.1%之间.根据cp基因核苷酸序列绘制分子进化树,发现6个VNNV分离株在进化树同一分枝上,属于RGNNV基因型,与已报道的点带石斑鱼神经坏死病病毒(ECNNV)、巨石斑鱼神经坏死病病毒(ETNNV)及玛拉巴石斑鱼神经坏死病病毒(MGNNV)亲缘关系较近.试验结果表明,目前我国沿海养殖场发生的鱼类病毒性神经坏死病均由同一来源的病毒引起,该基因型的鱼类神经坏死病毒在我国沿海养殖的石斑鱼中广泛传播流行.     

休眠期不同的春小麦种子种皮结构形态观察

观察表明:休眠期不同的春小麦种子种皮结构,在细胞层次上没有实质性差异,而外表皮的细胞形状,排列明显不同。休眠期长的品种,外表皮细胞排列整齐而紧凑,呈长方形;休眠期短的品种,外表皮细胞排列疏松,不整齐,多呈卵圆形,种皮的厚度与休眠无关。小麦种皮主要通过限制胚部的氧气供应,及对胚起物理阻碍作用而诱导休眠。     

三种侵染百香果的马铃薯Y病毒属病毒外壳蛋白比较

<正>0 Introduction The family Potyviridae accounts for approximately 30%of know n plant viruses, infecting an extensive range of dicots and monocots and causing enormous damage in agriculture^[1]. The genus Potyvirus is the largest genus in this family and all members of the Potyvirus share similar common characteristics and a same genome organization. Virions of potyviruses are non-enveloped,flexuous,