AGAMOUS在花发育中的核心功能研究进展

花是植物重要的生殖器官,受到多种花发育因子的调控。AGAMOUS(AG)在花发育的不同阶段有着不同的表达模式,对于植物的繁殖和发育有着重要的作用。AG与其他花发育基因、蛋白之间的相互作用决定了植物花器官的形态建成。近年来研究发现,AG基因对于花序分生组织向花分生组织的转化起到了关键的调控作用,特别是它与WUSCHEL(WUS)基因的反馈调节途径促进了植物生殖器官的发育。本综述总结了AG基因在植物花发育调控网络中的作用及生物学功能,展望了花发育未来的研究方向与发展趋势。     

芥菜型油菜多室角果的解剖特征及遗传分析

采用石蜡切片、杂交和回交技术研究了芥菜型油菜多室材料J163角果的形态特征、单株产量性状构成和遗传控制机制。结果表明,J163的角果由4心皮发育而来,4个果瓣包围种子,2个假隔膜平行,将角果分隔成3个腔室;假隔膜发育稳定,无假隔膜发育障碍或中途退化而形成多室与两室角果嵌合现象;尽管多室材料的千粒重和单株有效角果数均小于两室材料,但多室材料每角粒数和单株产量显著提高,说明多室性状(每角粒数多)有利于提高油菜产量;J163多室性状受隐性核基因控制,无细胞质效应,J163和两室材料J248间在多室位点上存在2对基因差异,但J163的多室性状基因是否为2对独立隐性基因还需进一步研究。根据上述特点可认为J163是新型芥菜型油菜多室材料。     

《植物学》教材中“花”章节教学内容分析

从6个方面分析了《植物学》教材中关于"花"的教学内容:花是适合于繁殖作用的变态枝;花是被子植物特有的器官;雌蕊是被子植物的标志性特征;真花学说是理解花的结构、起源和被子植物系统演化的理论基础;被子植物和裸子植物的区别主要体现在花及其受精以及受精后的产物上;被子植物花的结构与裸子植物和蕨类植物对应结构的比较。     

巨峰葡萄心皮形态发育的研究

 对葡萄心皮融合过程以及雌蕊各部分形成进行了详细观察。在早期发育阶段心皮是分离的，随着发育心皮原基出现并不断分裂增长，基部对应两侧初生分生组织向中心靠拢，靠拢的心皮初生分生组织以远轴背腹面表皮细胞相互连合，进而细胞再分化变为薄壁细胞，心皮原基以折叠方式进行融合，融合细胞向上生长分化花柱和柱头，向下则构成子房组织，将子房隔成2室。3心室子房的形成可能有两种方式，即生殖后融合与特殊区域生殖后融合 、     

Identification of hydrolytic activities expressed by Aspergillus flavus grown on cotton carpel tissue

To identify proteins important for invasion into host plant tissue, Aspergillus flavus was cultured on medium containing cotton carpel tissue as the sole carbon source. We identified several hydrolases suggesting they are important as A. flavus virulence factors for plant colonization. Specifically, Aspergillus flavus AF13 secreted at least two endoxylanase activities and a pectolytic activity when grown on the cotton carpel tissue medium. A concentrated sample derived from the A. flavus growth medium (6-day) was subjected to gel filtration chromatography on a BioGel P-30 column. A major endoxylanase activity was separated from the other fungal-secreted proteins. Additional fungal secreted proteins were partially resolved by gel filtration chromatography on a BioGel P-60 column. Multiple proteins with molecular weights in the 20 to 70 kD range were present in the harvested fungal growth medium. Analysis of these fungal-secreted proteins by liquid chromatography/tandem mass spectrometry identified both endo- and exo-glucanase proteins, α-l-arabinofuranosidase, glucoamylase, α-amylase A, pectate lyase A, xylanase F1, acetylxylan esterase, glutaminase A, as well as conserved hypothetical proteins of unknown function. These proteins likely assist A. flavus in the maceration of plant cell walls, allowing for pathogenic entry and accession of host nutrient resources. Pectolytic and xylanolytic hydrolases, as well as glucanases, appear to be important A. flavus virulence factors.     

Aspergillus flavus-secreted proteins during an in vivo fungal-cotton carpel tissue interaction

Cotton bolls (Gossypium hirsutum) were inoculated with Aspergillus flavus to investigate extracellular hydrolases produced during infection. Fungal proteins from the infection site were isolated and analyzed by SDS-PAGE. Protein bands were excised and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). We identified several proteins including an exoglucanase 1 precursor (AFL2G_03805), a hypothetical protein similar to rhamnogalacturonan lyase A (AFL2G_05136), and a hypothetical protein similar to pectate lyase A (AFL2G_05954). We also matched three peptides to an oryzin precursor protein (AFL2G_01995). Our findings support the conclusion that glucanase, pectinolytic, and proteolytic proteins are important for fungal maceration of cotton carpel tissue during infection.     

氨基乙氧基乙烯甘氨酸( AVG) 处理对‘巨峰’葡萄胚珠和种子发育的影响

 ‘巨峰’葡萄开花前2 周用氨基乙氧基乙烯甘氨酸( 2-aminoethxyvinlglycine, AVG)100 mg!L^-1处理可以明显增加有核果粒率和种子数。人工授粉24 h 后, 子房中的花粉管伸长快于对照, 花粉管生长状况也优于对照。这是由于AVG 处理降低了雌蕊中阻碍花粉管伸长物质的活性, 同时可以改善胚囊发育, 提高正常胚囊率和增加子房中的胚珠数和心皮数, 这可能为促进受精和增加受精机会创造了条件。     

Immunohistochemical investigation of cotton carpel tissue exposed to xylanolytic hydrolases of Aspergillus flavus

Cotton carpel tissue (35–45 days post-anthesis) that had been treated with a mixture of xylanolytic hydrolases derived from Aspergillus flavus was subjected to immunocytochemical analysis. Microscopic examination of treated tissues revealed severe degradation of the secondary wall structure. Control tissue cells revealed the presence of high concentrations of xylans/arabinoxylans throughout the cell wall, as well as significant concentrations of arabinogalactan proteins in secondary wall structure. Carpel cells treated with a mixture of A. flavus-produced xylanolytic hydrolases showed a much reduced presence of labeling by xylan-specific antibodies on the inner wall surface, suggesting a severe loss of these plant polysaccharides in the secondary wall structure. Carpel exposure to a purified 14 kD endoxylanase from A. flavus also resulted in a severe reduction of xylans from secondary wall structure, although penetration of the tissue was not as dramatic. Arabinogalactan proteins were not as severely affected by the xylanolytic hydrolases. Comparison of control tissue with hydrolase-treated tissue stained with toluidine blue revealed an apparent reduction in wall thickness, supporting the conclusion of secondary wall structure degradation. Interestingly, the pectins could only be detected in the samples treated with xylanolytic enzymes, indicating that the pectins were being masked by xylans. These results are consistent with the conclusion that the xylanolytic hydrolase complex of A. flavus is a critical factor for host cell wall maceration and may represent another important fungal virulence factor, in addition to pectolytic hydrolase activities.