水稻与稻瘟病菌非亲和性互作中重要防御酶活性变化规律研究

 选以CO39为背景的水稻抗稻瘟病近等基因系,与稻瘟菌生理小种ZC₁₃(菌株97-151a)组成的3类典型非亲和性互作,以亲和性互作为对照,对各互作中过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、几丁质酶及β-1,3-葡聚糖酶的活性变化规律进行了系统研究。完全非亲和性互作C101A51/97-151a、高度非亲和性互作C101L AC/97-151a及中度非亲和性互作C104 PKT/97-151a,POD比活性接种后即开始明显升高,48h前达到高峰,升高趋势一直持续到7d完全显症时,幅度基本与各互作非亲和程度呈正相关;亲和性互作CO39/97-151a接种后40 h POD比活性才开始升高,4~6 d达到高峰,峰值也较大。3类非亲和性互作PAL比活性在接种后0 h或16 h开始较明显升高,整个互作中形成3~4个较明显的峰;亲和性互作中PAL比活性一直明显下降。3类非亲和性互作外切几丁质酶比活性接种后即开始升高,基本一直保持升高趋势,在40 h前幅度较大,并形成1~3个较高的峰;亲和性互作外切几丁质酶比活性接种后即开始大幅度升高直至完全显症,48h后幅度远高于非亲和性互作。3类非亲和性互作β-1,3-葡聚糖酶比活性在24 h内开始较明显升高,在48h前形成2~3个较明显的峰;亲和性互作在接种后β-1,3-葡聚糖酶比活性即开始升高,在48h后显著高于非亲和性互作。讨论了POD、PAL、几丁质酶及β-1,3-葡聚糖酶参与水稻抗稻瘟病的可能性。     

中生菌素对水稻白叶枯病的防治机制

对不同白叶枯病抗性水稻品种用200μg/ml中生菌素55℃温汤药液浸种，自然降温，秧田3—4叶期和移栽前5d各用30μg/ml中生菌素处理后，于成株期剪叶接种白叶枯病菌。结果表明中生菌素前期处理，于成株期接种白叶枯病菌时，高抗、中等抗性和感病品种中过氧化物酶、苯丙氨酸解氨酶和多酚氧化酶3种酶活性都有不同程度的提高，且以中等抗性品种酶活提高最多，接种24和48h，3种酶活性较清水对照分别增加26．92％、26．74％、24．06％和7．09％、1．31％、1．60％。盆栽试验表明，中生菌素对中抗品种的防治效果最好，达58．4％。说明中生菌素对水稻防御酶活性的诱激作用是其防治白叶枯病的机制之一。     

北青龙衣褐变机制的研究

北青龙衣在由鲜品到干品的贮藏期间会出现失水、颜色变深等褐变现象。研究该褐变过程发生的机制,为控制褐变、提高药材的稳定性提供试验依据。采用北青龙衣鲜果果皮,4℃低温贮藏,研究其褐变度(browning degree,BD)、多酚氧化酶(polyphenol oxidase,PPO)、苯丙氨酸解氨酶(phenylalanine ammonialyase,PAL)、过氧化物酶(peroxidase,POD)活性变化、丙二醛(malondialdehyde,MDA)、总多酚(total polyphenols,TP)、还原糖含量及维生素C(Vitamin C,VC)含量变化。试验数据显示果皮颜色变深、TP含量下降、PPO活性降低、PAL活性上升、SOD和POD活性先上升后下降、MDA含量升高、还原糖和VC含量下降。BD与PPO、SOD、POD活性和TP含量呈显著负相关,与PAL活性呈显著正相关,与VC和还原糖无显著相关性。北青龙衣贮藏过程中发生了酶促褐变和非酶褐变,且以酶促褐变为主,PPO在酶促褐变中可能起主要作用。     

烟草氨基酸代谢及其调控机制

综述了植物氨同化以及烟草中苯丙氨酸代谢、脯氨酸代谢、美拉德反应及其与烟叶风味和品质关系的研究进展,并分析了环境因素对烟草氨基酸代谢的影响,为深入研究氨基酸对烟叶品质和风味影响的机制奠定了基础。     

Influence of Abscisic Acid and the Abscisic Acid Biosynthesis Inhibitor, Norflurazon, on Interactions Between Phytophthora sojae and Soybean (Glycine max)

A comparison was made of the effects of abscisic acid (ABA) and the ABA biosynthesis inhibitor, norflurazon on the interaction between soybean leaves and Phytophthora sojae. Inoculation of leaves of cv. Harosoy resulted in a compatible interaction typified by the presence of spreading, water soaked lesions with ill-defined margins while inoculation of cv. Haro 1272 resulted in an incompatible interaction with lesions restricted to the inoculation site. Activity of phenylalanine ammonia lyase (PAL) slowly increased in the compatible interaction but in the incompatible interaction there was a rapid rise in activity within 8h after inoculation. When Haro 1272 plants were treated with ABA the normally incompatible interaction with race 1 was changed to what resembled a compatible interaction and activity of PAL was reduced to control levels. There was no visible effect on the compatible combination. In contrast when plants of cv. Harosoy were treated with norflurazon the normally compatible interaction with race 1 was changed to that which resembled an incompatible interaction and PAL activity increased to high levels rapidly. There was no effect of norflurazon on the incompatible interaction of cv. Haro 1272 with race 1. Stomata on leaves of cv. Harosoy treated with norflurazon closed within 2h of inoculation resembling the response of stomata in normal incompatible interactions but not compatible interactions where stomata remained open. On leaves of cv. Harosoy treated with norflurazon at sites 3 and 20mm from the inoculation point stomata also closed. These results extend and confirm the idea that ABA is a molecule that may regulate the outcome of the interaction between soybeans and P. sojae.     

杨盘二孢激发子的分离及稳定性研究

 从杨盘二孢的培养滤液和菌丝中获得2种激发子粗提物,分别测定其糖和蛋白质的含量,发现滤液激发子粗提物(CFE)糖和蛋白质的含量分别为41.07和40mg/mL,菌丝激发子粗提物(CME)糖和蛋白质含量分别为48.07和55mg/mL。滤液激发子粗提物对温度不敏感而对碱性条件敏感;菌丝激发子粗提物对酸碱不敏感而对温度敏感。用Sephadex G-100柱层析的方法初步纯化2种激发子,并且菌丝激发子粗提物过柱后得到2个活性组分J14和J25;滤液激发子粗提物过柱后获得2个活性组分L9和L16。将4个组分进行烟草叶片过敏反应和I-895杨酶活性的诱导,结果表明,菌丝激发子强活性物质集中在J14组分;而滤液激发子强活性物质集中在L9组分。     

Some compatible Rhizobium leguminosarum strains in peas decrease infections when parasitised by Orobanche crenata

Orobanche crenata (crenate broomrape) produces serious damage to many legume crops and particularly becomes a limiting factor for pea production in the Mediterranean basin. Nodulation effects on pea–broomrape relationships were studied using the commercial pea cultivar Douce de Provence and different Rhizobium strains using pot and Petri dish experiments. First, the benefit of bacterial inoculation on plant growth and efficiency of N incorporation were demonstrated for two isolates, P.SOM and P.1236. These isolates did not influence parasite germination induced by the artificial stimulant, GR24. In contrast, pea root inoculation with P.SOM and P.1236 isolates led to a reduced root infection by O. crenata , resulting from a lower Orobanche germination rate close to pea roots and a limited capacity of the parasitic seedlings to develop tubercles. Broomrape necrosis was observed both before and after parasite attachment to inoculated pea roots. Concomitantly, reduction in infection was accompanied by enhanced peroxidase activity and constantly high phenylalanine ammonia lyase activity in pea roots. These data suggest the involvement of these enzymes in pea resistance to crenate broomrape induced by the compatible rhizobia. Management of Orobanche via crop selection based on these enzyme systems is a viable option.     

红檵木叶色变化的生理生化研究

红檵木(Loropetalum chinense var.rubrum)在春季新叶初发时,花红叶红,且叶片红艳可人,具有很高的观赏价值.但随着叶龄的增大,叶色发生较大变化,在初夏叶色变为暗红色,到了盛夏高温季节,叶色几乎变成了绿色,出现了生产上称之的"高温返青"现象.     

锥栗对栗疫病的抗性与苯丙氨酸解氨酶的关系

健康的锥栗(Castanea henryi)皮层中,苯丙氨酸解氨酶(PAL)比活力与抗感病性之间不相关.不同抗病性的锥栗品种接种栗疫菌(Cryphonectria parastttca)后,PAL比活力均上升,接种144 h后,PAL比活力抗病性强的品种比抗病性弱的品种高.接种前以及接种后的各个时间内,木质素含量都是抗病品种比感病品种高.绿原酸的含量与品种的抗病性之间不呈规律性的相关,从绿原酸对栗疫菌菌丝生长影响的测定结果可知,锥栗体内的绿原酸浓度不足以影响栗疫菌.可见,接种后的皮层PAL比活力以及接种前、后的皮层木质素含量可作为衡量锥栗抗病性强弱的指标.     

植物保卫素东莨菪内酯对烟草的诱导抗性研究进展

东莨菪内酯属香豆素类化合物,是烟草中重要的植物保卫素,能抗烟草花叶病、灰霉病、野火版、青枯病、黑胫病等多种病害,其在烟草组织中通过苯丙氨酸解氨酶(PAL)调控合成,当受到不良环境影响或者外源物质(茉莉酸甲酯、2,4-D、核黄素、细胞分裂素等)诱导时,东莨菪内酯在烟草葡萄糖基转移酶(TOGTs)调控转化为东莨菪苷转移到液泡中发挥抗病作用。该文综述了东莨菪内酯对烟草中的生物合成及诱导抗性的相关研究,以期为提高烟草的抗病性及防治提供理论依据。