青海地区萝卜黑心病病原

2018-2021年自青海西宁及其周边地区采集萝卜黑心病样品66份,采用组织分离法对样品进行分离并纯化,获得80株轮枝菌属菌株,编号为VL1-VL80。供试菌株在PDA上生长十分缓慢,培养后产生微菌核和轮枝状分生孢子梗。微菌核不规则形,53.91-164.42×8.91-29.81 μm,平均长宽比大于2。分生孢子透明且较长,5.35-9.31×2.12-4.78 μm,不产生厚垣孢子和休眠菌丝。ITS和ACT序列测定分析表明,供试菌株均属于长孢轮枝菌A1/D1株系。测定4株代表性菌株的ITS、ACT、EF、GPD、OX和TS的片段序列,分别构建ITS片段和多基因系统发育树,ITS发育树表明供试菌株与长孢轮枝菌位于同一个分支,多基因系统发育分析表明供试菌株与长孢轮枝菌A1和D1株系位于同一个分支。致病性测定结果表明,可侵染萝卜引起黑心病症状。以上研究结果表明,青海地区萝卜黑心病菌病原为长孢轮枝菌A1/D1株系,这是我国首次报道长孢轮枝菌A1/D1株系。     

一株纤维素降解真菌的筛选、鉴定及酶学性质分析

通过对富含枯枝败叶的土壤样品进行富集培养,利用刚果红纤维素培养基初筛和酶活测定复筛得到产纤维素酶的一株真菌,将其命名为GC2-2,并对该菌株进行鉴定及酶学性质研究。结果表明该菌株是一株耐高温、碱性纤维素酶的真菌GC2-2。通过18S rDNA分子克隆测定,该菌为球孢枝孢菌,其滤纸酶的活力优于CMC酶的活力。该菌所产酶的最适反应条件为温度35°C,最适pH值7.5。     

低温与GA_3诱导菠萝黑心病的生理机制

菠萝黑心病是PPO催化氧化酚类物质形成褐色产物所致。低温或GA_3处理提高了PPO活性及其底物——儿茶酚、绿原酸和咖啡酸的含量,也导致了PAL活性增加;低温还使乙烯释放率增大。这些变化均有利于黑心病的发生和发展。     

黑蛋巢菌属的新种新变种

本文报道了采自云南的黑蛋巢菌属(Cyathus Haller:Pers.)两个新种,一个新变种。它们分别是:巨孢黑蛋巢Cyathut megasporus Ren et Zhou、角状黑蛋巢Cyathus cornucop-ioides Zhou et Ren和新西兰黑蛋巢卵形孢变种C.no(?)ae-zeelandiae Tul.var.ovisporus R-en et Zhou。模式标本均保存在西南林学院真菌标本室。     

蜡蚧轮枝菌和球孢白僵菌的共发酵

【目的】球孢白僵菌(Beauveria bassiana)和蜡蚧轮枝菌(Verticillium lecanii)是国内外目前研究应用最广泛的杀虫生防真菌,欲扩大其防治范围、增强防治效果、降低生防成本。【方法】采用共发酵技术,通过组合菌株产孢能力和杀虫毒力比较试验,确定蜡蚧轮枝菌和球孢白僵菌共发酵的可行性。【结果】蜡蚧轮枝菌L-31和球孢白僵菌Q-55共发酵的最佳配比为1:1时,按10%总量接种于发酵培养液中(培养液按酵母膏5.0 g/L、葡萄糖20.0 g/L、麦芽糖提取物5.0 g/L、KH2PO43.0 g/L、黄小米200.0 g/L,pH 6.5配制),23.0°C±0.1°C恒温静置发酵12 d,共发酵液的含孢量可达1×109CFU/mL以上,杀虫毒力比较强,其对温室白粉虱和菜青虫可同时显效,处理9 d后的致死中浓度LC50分别为2.09×104±0.12 CFU/mL和3.17×105±0.11 CFU/mL,发酵液浓度为1×108CFU/mL时的致死中时间LT50分别为2.11±0.14 d和4.27±0.43 d,温室小区试验校正防效在80%以上,与其各单一菌株发酵液的防效之间存在显著性差异。【结论】通过两株生防真菌的共发酵研究,为杀虫真菌的扩谱增效以及植物害虫的有效防治提供科学依据和有效途径。     

萝卜不同抗源对黑腐病抗性的遗传分析

不同抗病基因的挖掘是作物持久抗性遗传改良的基础。本研究利用2份抗黑腐病(Xanthamonas campestris pv.campestris)萝卜(Raphanus sativus L.)材料(KB10Q-22、KB10Q-24)和1份感病材料(KB10Q-33)构建了2个F2群体,采用苗期剪叶+喷雾法接种黑腐病菌Xcc8004进行抗病性鉴定。应用P1、P2、F1、F24个世代的数量性状主基因+多基因混合遗传分析方法,研究了萝卜2个不同抗源抗黑腐病的遗传规律,结果表明2份材料的遗传规律不同。以KB10Q-22为母本的F1植株表现为抗病,其遗传模型为E_0模型,即2对加性-显性-上位性主基因+加性-显性-上位性多基因模型;而以KB10Q-24为母本的F1植株表现为感病,其遗传模型为D_0模型,即1对加性-显性主基因+加性-显性-上位性多基因模型。两群体主基因遗传率分别为87.73%和55.64%,抗性遗传以主基因为主。     

燕麦紫斑病的病原

2013年8月在甘肃省通渭县的一块燕麦田中,叶片和小穗上出现大量紫色病斑,病株率达100％.采用组织分离法得到核腔菌属Pyrenophora(synonym:Drechslera)真菌.通过Koch's法则明确了菌株ASA-13的致病性:在8-22℃下,接种植株产生紫色叶斑,在20-25℃下,接种植株产生中心黑色、周围...     

小棒柄菌属和射棒孢属的新种

生在山木患(Harpullia cupanioides Roxb．)叶上的丝孢菌(Hyphomycetes)个新种：瘤孢小棒柄菌(Microclava tuberospora G. C. Zhao et N Li sp nov)和黑孢射棒孢菌(Actinocladium alrosporum G．C．Zhao et N. Li sp．nov)。文中对这两种真菌作了描述和比较。     

子囊菌黑陷球壳属的种

黑陷球壳属是单囊壁子囊菌,属内许多种的定义一直不明确,该属应该归于哪一科等问题一直存在争议。文中通过对资料的搜集整理和模式标本的重新鉴定研究,确认了黑陷球壳属9个种;49个种归并到其他属;12个种由于不符合该属的特征,应予排除,但尚需确定名称;44个种由于模式标本材料太差或无法搜寻到模式标本,作为可疑种;另有11个种尚需搜寻模式标本重新研究。     

萝卜种质资源对黑腐病的抗性鉴定与筛选

对40份初选萝卜种质分别接种Xcc8004和XccBJ两个菌株,进行黑腐病苗期抗性鉴定,对其中8份代表性萝卜种质肉质根切片接种Xcc8004进行抗性鉴定和27份萝卜种质幼苗接种8个效应物基因进行过敏反应鉴定。结果表明:不同萝卜种质苗期对黑腐病的抗性存在显著差异,筛选出高抗Xcc8004的材料3份、抗病1份、中抗4份,高抗XccBJ的材料1份、抗病2份、中抗5份。萝卜苗期对Xcc8004和XccBJ的抗病性极显著相关,幼苗和肉质根对Xcc8004的抗病性极显著相关。筛选出17份对不同效应物表现过敏反应的萝卜种质。对效应物XC₀241表现过敏反应的种质数最多,对XC₀542和XC₀541表现过敏反应的种质数次之。不同抗源对不同效应物的过敏反应程度有所不同。稳定可靠抗病资源的获得为萝卜抗病育种和抗病机理的深入研究提供了基础材料。     

青海西宁大山雀的鸣唱模式分析

2012年4~5月在西宁市录制大山雀的鸣声,用Avisoft-SASLab Pro声音分析软件分析其鸣唱结构。已有的录音记录分析表明西宁大山雀个体拥有1~4种鸣唱型,鸣唱短语由1~5个音素构成。西宁大山雀2音素短语的长度低于低海拔地区,具有较快的鸣唱型转换频率。     

Effects of pollen load size and composition on pollen donor performance in wild radish, Raphanus sativus (Brassicaceae)

A critical concern in the debate over the importance of sexual selection in plants is whether the nonrandom mating demonstrable in greenhouse crosses can occur in the field. Field populations likely experience smaller and more variable pollen load sizes than those that have been used in many greenhouse experiments. Therefore, we performed a greenhouse experiment in which we varied both pollen load size and composition in wild radish, Raphanus sativus, and examined the paternity of seeds. We used five maternal plants and four pairs of pollen donors. We were able to produce pollen loads of 40, 118, and 258 grains per stigma. The smallest of the pollen loads was scant enough to result in a slight, but significant reduction in seed number per fruit. While variation in pollen load composition significantly affected the proportions of seeds fathered by different donors, variation in pollen load size did not. The relative performance of different donors was constant across pollen load sizes, suggesting that, for this species, differential performance of pollen donors can occur at pollen load sizes that are likely to occur in field populations.     

Increase in calmodulin level in the early phases of radish seed (Raphanus sativus) germination

Abstract Calmodulin (Cam), the heat-stable, ubiquitous, Ca²⁺-dependent regulator protein, has been purified to apparent homogeneity from germinating radish seeds (Raphanus sativus). The characteristics of radish Cam-molecular weight, absorption spectrum, Ca²⁺-dependent activation of brain phosphodiesterase (PDE)-are very similar to those described for Cam from other plant materials. Radish Cam, like other plant Cam, shows some differences to Cam of calf brain. The total amount of Cam in radish embryos at 24 h of germination is ca. 37 μg g⁻¹ fresh weight. Approximately 95% of the total amount of Cam is present in the soluble fraction (supernatant at 100,000 g). The level in the embryo axis strongly increases in the first 24 h of germination (+540%); this increase is strongly reduced when the germination is inhibited by abscisic acid (ABA). In the presence of Ca²⁺, no ‘free’ Cam (i.e. not bound to other structures) is present in the soluble fraction, suggesting that, during early germination, Cam level is a limiting factor for the activities of Ca²⁺ -Cam-dependent systems. These studies suggest that Cam plays an important role in the early phases of seed germination. An inhibitor of the Ca²⁺-Cam-dependent phosphodiesterase is present in the soluble fraction from radish embryos; this substance decreases during germination. A possible role of this inhibitor during the early germination phases is hypothesized.     

Accumulation of metals and metalloids in radish (Raphanus sativus L.) and spinach (Spinacea oleracea L.) irrigated with domestic wastewater in the peri-urban areas of Khushab City,Pakistan

Accumulation of different metals and metalloids was assessed in two vegetables radish (Raphanus sativus L.) and spinach (Spinacea oleracea L.) irrigated with domestic wastewater in the peri-urban areas of Khushab City, Pakistan. In general, the metal and metalloid concentrations in radish and spinach were higher at site-II treated with sewage water than those found at site-I treated with canal water. In case of radish at both sites the levels of metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, and Pb) were below the permissible level except those of Mn, Ni, Mo, Cd, and Pb. At both sites, the transfer factor ranged from 0.047–228.3 mg kg^?1 with Cr having the highest transfer factor. The metal pollution index in soil was in the following order: As > Fe > Ni > Zn > Cd > Mo > Se > Co > Pb > Mn > Cr > Cu, respectively. While in case of spinach at both sites, the concentrations of metals and metalloids in vegetable samples irrigated with canal and sewage water were observed below the permissible level except Mn, Ni, Zn, Mo, and Pb. At both sites, the transfer factor ranged from 0.038–245.4 mg kg^?1 with Cr having the highest transfer factor. The metal pollution index in soil was in the following order: Cd > Ni > Co > Se > Mn > Zn > Mo > Pb > Fe > Cr > As > Cu, respectively.     

The use of image analysis to monitor the germination of seeds of broccoli (Brassica oleracea) and radish (Raphanus sativus)

To study broccoli and radish seed germination under different temperature regimes the germination test has been used to assess final germination percentage, start and rate. This method has been integrated with a computer‐aided image analysis test which is more accurate in monitoring the extent of imbibition phases through the assessment of seed area increase and timing of radicle emergence detected on single seeds. In addition, seed area increase has been used also to establish a close relationship with radicle elongation rate in the time range when ‘visible germination’ is scored by a classical germination test. The results suggest that this image analysis parameter may be considered as a reliable seed imbibition marker to integrate the germination parameters obtained by a germination test.     

Pollen donor performance can be consistent acrossmaternal plants in wild radish (Raphanus sativus,Brassicaceae): a necessary condition for the action of sexualselection

The possibility that sexual selection has played a role in theevolution of plant reproductive characters remains interesting, butcontroversial. One reason is that clear demonstration of the necessaryconditions for sexual selection is lacking. For sexual selection tooccur, differences in pollen donor performance must be consistent acrossmaternal plants and not be due to mechanisms such asself-incompatibility that produce interactions between maternal plantsand pollen donors. Here, I performed two experiments with wild radish totest whether differences in pollen donor performance are consistentacross maternal plants and not due to subtle effects of theincompatibility system. In the first, all maternal and paternal lineageshad different S-alleles. There were 16 maternal plants, four in each offour lineages and four pollen donors, one in each of four lineages. Rankorder of pollen donor performance, in terms of number of seeds siredafter mixed pollination, was highly consistent across maternal plantsand maternal lineages. In addition, maternal stress treatment had aneffect on mating success of pollen donors, but the effect was subtle anddid not affect the rank order of seeds sired by the four pollen donors.In the second experiment, pollinations were performed on both mature andimmature stigmas. Immature stigmas allowed some self seed set, so theincompatibility system was compromised. There was some nonrandom seedpaternity on both mature and immature stigmas. However, the amount ofnonrandom mating was less on immature stigmas. Taken together, theseexperiments show that the kind of consistent nonrandom mating necessaryfor sexual selection occurs in wild radish, but that the incompatibilitysystem and the mechanisms for sorting among compatible mates may overlapin time of development or in somepathways.     

Response to osmotic medium and fusicoccin by seeds of radish (Raphanus sativus) in the early phase of germination

The effect of increasing osmotic values of the medium (mannitol) on the growth and the response mechanisms of seeds of radish ( Raphanus sativus L., cv. Ton do Rosso Quarantino) during the early phase of germination was investigated in the presence or absence of fusicoccin (FC). Decreasing the water potential in the medium inhibited the growth and the evolution of protein synthesis and enhanced H⁺ extrusion, net uptake of K⁺ and malic acid synthesis. FC, which stimulates these latter functions, counteracted the inhibitory effect of the decreasing water potential of the medium on growth and protein synthesis. Neither in the absence nor in the presence of FC did decreasing water potential of the medium enhance the synthesis of soluble sugars and amino acids to support the osmotic pressure of the seeds. The osmotic and water potentials of the seeds increased during germination. FC made the increase more rapid, while mannitol kept both potentials low. The pressure potentials of the seeds also decreased with time, and both FC and mannitol enhanced this change. If the seeds were without turgor, the development of protein synthesis was blocked. The seeds counteract the effect of decreasing water potentials in the medium by: a) enhancing H⁺ extrusion (and, as a consequence, wall loosening and transport mechanisms) and the synthesis of malic acid as apparent in the presence of FC; b) regulating the osmotic potentials of the cells (with a lower dilution of the osmotic compounds present in the seeds due to the diminished uptake of water); c) controlling the growth through the effects of a) and b) on the pressure potentials (internal hydrostatic pressure) of the seeds and on protein synthesis.     

Involvement of Ca2+-calmodulin in Cd2+ toxicity during the early phases of radish (Raphanus sativus L.) seed germination

The toxicity of Cd²⁺in vivo during the early phases of radish (Raphanus sativus L.) seed germination and the in vitro Cd²⁺ effect on radish calmodulin (CaM) were studied. Cd²⁺ was taken up in the embryo axes of radish seeds; the increase in fresh weight of embryo axes after 24 h of incubation was inhibited significantly in the presence of 10 mmol m^?3 Cd²⁺ in the external medium, when the Cd²⁺ content in the embryo axes was c. 1.1 μmol g^?1 FW. The reabsorption of K⁺, which characterizes germination, was inhibited by Cd²⁺, suggesting that Cd²⁺ affected metabolic reactivation. The slight effect of Cd²⁺ on the transmembrane electric potential of the cortical cells of the embryo axes excluded a generalized toxicity of Cd²⁺ at the plasma membrane level. After 24 h of incubation, Cd²⁺ induced no increase in total acid-soluble thiols and Cd²⁺-binding peptides able to reduce Cd²⁺ toxicity. Ca²⁺ added to the incubation medium partially reversed the Cd²⁺-induced inhibition of the increase in fresh weight of embryo axes and concomitantly reduced Cd²⁺ uptake. Equilibrium dialysis experiments indicated that Cd²⁺ bound to CaM and competed with Ca²⁺ in this binding. Cd²⁺ inhibited the activation of Ca²⁺-CaM-dependent calf-brain phosphodiesterase, inhibiting the Ca²⁺-CaM active complex. Cd²⁺ reduced the binding of CaM to the Ca²⁺-CaM binding enzymes present in the soluble fraction of the embryo axes of radish seeds. The possibility that Cd²⁺ toxicity in radish seed germination is mediated by the action of Cd²⁺ on Ca²⁺-CaM is discussed in relation to the in vivo and in vitro effects of Cd²⁺.